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Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1	<HTML><HEAD>
				2	<TITLE>BASH(1) Manual Page</TITLE>
				3	</HEAD>
				4	<BODY><TABLE WIDTH=100%>
				5	<TR>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	6	<TH ALIGN=LEFT width=33%>BASH(1)<TH ALIGN=CENTER width=33%>2014 February 2<TH ALIGN=RIGHT width=33%>BASH(1)
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7	</TR>
				8	</TABLE>
				9	<BR><A HREF="#index">Index</A>
				10	<HR>
				11
				12
				13
				14
				15
				16
				17
				18
				19
				20
				21
				22
				23
				24
				25
				26
				27
				28
				29
				30	<A NAME="lbAB"> </A>
				31	<H3>NAME</H3>
				32
				33	bash - GNU Bourne-Again SHell
				34	<A NAME="lbAC"> </A>
				35	<H3>SYNOPSIS</H3>
				36
				37	<B>bash</B>
				38
				39	[options]
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	40	[command_string \| file]
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	41	<A NAME="lbAD"> </A>
				42	<H3>COPYRIGHT</H3>
				43
				44
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	45	Bash is Copyright © 1989-2013 by the Free Software Foundation, Inc.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	46	<A NAME="lbAE"> </A>
				47	<H3>DESCRIPTION</H3>
				48
				49	<B>Bash</B>
				50
				51	is an <B>sh</B>-compatible command language interpreter that
				52	executes commands read from the standard input or from a file.
				53	<B>Bash</B>
				54
				55	also incorporates useful features from the <I>Korn</I> and <I>C</I>
				56	shells (<B>ksh</B> and <B>csh</B>).
				57	<P>
				58
				59	<B>Bash</B>
				60
				61	is intended to be a conformant implementation of the
				62	Shell and Utilities portion of the IEEE POSIX specification
				63	(IEEE Standard 1003.1).
				64	<B>Bash</B>
				65
				66	can be configured to be POSIX-conformant by default.
				67	<A NAME="lbAF"> </A>
				68	<H3>OPTIONS</H3>
				69
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	70	All of the single-character shell options documented in the
				71	description of the <B>set</B> builtin command can be used as options
				72	when the shell is invoked.
				73	In addition, <B>bash</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	74	interprets the following options when it is invoked:
				75	<P>
				76
				77
				78	<DL COMPACT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	79	<DT><B>-c</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	80
				81	<DD>
				82	If the
				83	<B>-c</B>
				84
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	85	option is present, then commands are read from the first non-option argument
				86	<I>command_string</I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	87
				88	If there are arguments after the
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	89	<I>command_string</I>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	90
				91	they are assigned to the positional parameters, starting with
				92	<B>$0</B>.
				93
				94	<DT><B>-i</B>
				95
				96	<DD>
				97	If the
				98	<B>-i</B>
				99
				100	option is present, the shell is
				101	<I>interactive</I>.
				102
				103	<DT><B>-l</B>
				104
				105	<DD>
				106	Make
				107	<B>bash</B>
				108
				109	act as if it had been invoked as a login shell (see
				110	<FONT SIZE=-1><B>INVOCATION</B>
				111
				112	</FONT>
				113	below).
				114	<DT><B>-r</B>
				115
				116	<DD>
				117	If the
				118	<B>-r</B>
				119
				120	option is present, the shell becomes
				121	<I>restricted</I>
				122
				123	(see
				124	<FONT SIZE=-1><B>RESTRICTED SHELL</B>
				125
				126	</FONT>
				127	below).
				128	<DT><B>-s</B>
				129
				130	<DD>
				131	If the
				132	<B>-s</B>
				133
				134	option is present, or if no arguments remain after option
				135	processing, then commands are read from the standard input.
				136	This option allows the positional parameters to be set
				137	when invoking an interactive shell.
				138	<DT><B>-D</B>
				139
				140	<DD>
				141	A list of all double-quoted strings preceded by <B>$</B>
				142	is printed on the standard output.
				143	These are the strings that
				144	are subject to language translation when the current locale
				145	is not <B>C</B> or <B>POSIX</B>.
				146	This implies the <B>-n</B> option; no commands will be executed.
				147	<DT><B>[-+]O [</B><I>shopt_option</I>]
				148
				149	<DD>
				150	<I>shopt_option</I> is one of the shell options accepted by the
				151	<B>shopt</B> builtin (see
				152	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				153
				154	</FONT>
				155	below).
				156	If <I>shopt_option</I> is present, <B>-O</B> sets the value of that option;
				157	<B>+O</B> unsets it.
				158	If <I>shopt_option</I> is not supplied, the names and values of the shell
				159	options accepted by <B>shopt</B> are printed on the standard output.
				160	If the invocation option is <B>+O</B>, the output is displayed in a format
				161	that may be reused as input.
				162	<DT><B>--</B>
				163
				164	<DD>
				165	A
				166	<B>--</B>
				167
				168	signals the end of options and disables further option processing.
				169	Any arguments after the
				170	<B>--</B>
				171
				172	are treated as filenames and arguments. An argument of
				173	<B>-</B>
				174
				175	is equivalent to <B>--</B>.
				176
				177	</DL>
				178	<P>
				179
				180	<B>Bash</B>
				181
				182	also interprets a number of multi-character options.
				183	These options must appear on the command line before the
				184	single-character options to be recognized.
				185	<P>
				186
				187
				188	<DL COMPACT>
				189	<DT><B>--debugger</B>
				190
				191	<DD>
				192	Arrange for the debugger profile to be executed before the shell
				193	starts.
				194	Turns on extended debugging mode (see the description of the
				195	<B>extdebug</B>
				196
				197	option to the
				198	<B>shopt</B>
				199
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	200	builtin below).
				201	<DT><B>--dump-po-strings</B>
				202
				203	<DD>
				204	Equivalent to <B>-D</B>, but the output is in the GNU <I>gettext</I>
				205	<B>po</B> (portable object) file format.
				206	<DT><B>--dump-strings</B>
				207
				208	<DD>
				209	Equivalent to <B>-D</B>.
				210	<DT><B>--help</B>
				211
				212	<DD>
				213	Display a usage message on standard output and exit successfully.
				214	<DT><B>--init-file</B> <I>file</I><DD>
				215
				216	<DT><B>--rcfile</B> <I>file</I><DD>
				217
				218	Execute commands from
				219	<I>file</I>
				220
				221	instead of the standard personal initialization file
				222	<A HREF="file:~/.bashrc"><I>~/.bashrc</I></A>
				223
				224	if the shell is interactive (see
				225	<FONT SIZE=-1><B>INVOCATION</B>
				226
				227	</FONT>
				228	below).
				229	<DT><B>--login</B>
				230
				231	<DD>
				232	Equivalent to <B>-l</B>.
				233	<DT><B>--noediting</B>
				234
				235	<DD>
				236	Do not use the GNU
				237	<B>readline</B>
				238
				239	library to read command lines when the shell is interactive.
				240	<DT><B>--noprofile</B>
				241
				242	<DD>
				243	Do not read either the system-wide startup file
				244
				245	<A HREF="file:/etc/profile"><I>/etc/profile</I></A>
				246
				247	or any of the personal initialization files
				248	<A HREF="file:~/.bash_profile"><I>~/.bash_profile</I></A>,
				249
				250	<A HREF="file:~/.bash_login"><I>~/.bash_login</I></A>,
				251
				252	or
				253	<A HREF="file:~/.profile"><I>~/.profile</I></A>.
				254
				255	By default,
				256	<B>bash</B>
				257
				258	reads these files when it is invoked as a login shell (see
				259	<FONT SIZE=-1><B>INVOCATION</B>
				260
				261	</FONT>
				262	below).
				263	<DT><B>--norc</B>
				264
				265	<DD>
				266	Do not read and execute the personal initialization file
				267	<A HREF="file:~/.bashrc"><I>~/.bashrc</I></A>
				268
				269	if the shell is interactive.
				270	This option is on by default if the shell is invoked as
				271	<B>sh</B>.
				272
				273	<DT><B>--posix</B>
				274
				275	<DD>
				276	Change the behavior of <B>bash</B> where the default operation differs
				277	from the POSIX standard to match the standard (<I>posix mode</I>).
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	278	See
				279	<FONT SIZE=-1><B>SEE ALSO</B>
				280
				281	</FONT>
				282	below for a reference to a document that details how posix mode affects
				283	bash's behavior.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	284	<DT><B>--restricted</B>
				285
				286	<DD>
				287	The shell becomes restricted (see
				288	<FONT SIZE=-1><B>RESTRICTED SHELL</B>
				289
				290	</FONT>
				291	below).
				292	<DT><B>--verbose</B>
				293
				294	<DD>
				295	Equivalent to <B>-v</B>.
				296	<DT><B>--version</B>
				297
				298	<DD>
				299	Show version information for this instance of
				300	<B>bash</B>
				301
				302	on the standard output and exit successfully.
				303
				304	</DL>
				305	<A NAME="lbAG"> </A>
				306	<H3>ARGUMENTS</H3>
				307
				308	If arguments remain after option processing, and neither the
				309	<B>-c</B>
				310
				311	nor the
				312	<B>-s</B>
				313
				314	option has been supplied, the first argument is assumed to
				315	be the name of a file containing shell commands.
				316	If
				317	<B>bash</B>
				318
				319	is invoked in this fashion,
				320	<B>$0</B>
				321
				322	is set to the name of the file, and the positional parameters
				323	are set to the remaining arguments.
				324	<B>Bash</B>
				325
				326	reads and executes commands from this file, then exits.
				327	<B>Bash</B>'s exit status is the exit status of the last command
				328	executed in the script.
				329	If no commands are executed, the exit status is 0.
				330	An attempt is first made to open the file in the current directory, and,
				331	if no file is found, then the shell searches the directories in
				332	<FONT SIZE=-1><B>PATH</B>
				333
				334	</FONT>
				335	for the script.
				336	<A NAME="lbAH"> </A>
				337	<H3>INVOCATION</H3>
				338
				339	A <I>login shell</I> is one whose first character of argument zero is a
				340	<B>-</B>,
				341
				342	or one started with the
				343	<B>--login</B>
				344
				345	option.
				346	<P>
				347
				348	An <I>interactive</I> shell is one started without non-option arguments
				349	and without the
				350	<B>-c</B>
				351
				352	option
				353	whose standard input and error are
				354	both connected to terminals (as determined by
				355	<I>isatty</I>(3)),
				356
				357	or one started with the
				358	<B>-i</B>
				359
				360	option.
				361	<FONT SIZE=-1><B>PS1</B>
				362
				363	</FONT>
				364	is set and
				365	<B>$-</B>
				366
				367	includes
				368	<B>i</B>
				369
				370	if
				371	<B>bash</B>
				372
				373	is interactive,
				374	allowing a shell script or a startup file to test this state.
				375	<P>
				376
				377	The following paragraphs describe how
				378	<B>bash</B>
				379
				380	executes its startup files.
				381	If any of the files exist but cannot be read,
				382	<B>bash</B>
				383
				384	reports an error.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	385	Tildes are expanded in filenames as described below under
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	386	<B>Tilde Expansion</B>
				387
				388	in the
				389	<FONT SIZE=-1><B>EXPANSION</B>
				390
				391	</FONT>
				392	section.
				393	<P>
				394
				395	When
				396	<B>bash</B>
				397
				398	is invoked as an interactive login shell, or as a non-interactive shell
				399	with the <B>--login</B> option, it first reads and
				400	executes commands from the file <A HREF="file:/etc/profile"><I>/etc/profile</I></A>, if that
				401	file exists.
				402	After reading that file, it looks for <A HREF="file:~/.bash_profile"><I>~/.bash_profile</I></A>,
				403	<A HREF="file:~/.bash_login"><I>~/.bash_login</I></A>, and <A HREF="file:~/.profile"><I>~/.profile</I></A>, in that order, and reads
				404	and executes commands from the first one that exists and is readable.
				405	The
				406	<B>--noprofile</B>
				407
				408	option may be used when the shell is started to inhibit this behavior.
				409	<P>
				410
				411	When a login shell exits,
				412	<B>bash</B>
				413
				414	reads and executes commands from the file <A HREF="file:~/.bash_logout"><I>~/.bash_logout</I></A>, if it
				415	exists.
				416	<P>
				417
				418	When an interactive shell that is not a login shell is started,
				419	<B>bash</B>
				420
				421	reads and executes commands from <A HREF="file:~/.bashrc"><I>~/.bashrc</I></A>, if that file exists.
				422	This may be inhibited by using the
				423	<B>--norc</B>
				424
				425	option.
				426	The <B>--rcfile</B> <I>file</I> option will force
				427	<B>bash</B>
				428
				429	to read and execute commands from <I>file</I> instead of <A HREF="file:~/.bashrc"><I>~/.bashrc</I></A>.
				430	<P>
				431
				432	When
				433	<B>bash</B>
				434
				435	is started non-interactively, to run a shell script, for example, it
				436	looks for the variable
				437	<FONT SIZE=-1><B>BASH_ENV</B>
				438
				439	</FONT>
				440	in the environment, expands its value if it appears there, and uses the
				441	expanded value as the name of a file to read and execute.
				442	<B>Bash</B>
				443
				444	behaves as if the following command were executed:
				445	<P>
				446	<DL COMPACT><DT><DD>
				447	<TT>if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi</TT>
				448
				449	</DL>
				450
				451	<P>
				452	but the value of the
				453	<FONT SIZE=-1><B>PATH</B>
				454
				455	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	456	variable is not used to search for the filename.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	457	<P>
				458
				459	If
				460	<B>bash</B>
				461
				462	is invoked with the name
				463	<B>sh</B>,
				464
				465	it tries to mimic the startup behavior of historical versions of
				466	<B>sh</B>
				467
				468	as closely as possible,
				469	while conforming to the POSIX standard as well.
				470	When invoked as an interactive login shell, or a non-interactive
				471	shell with the <B>--login</B> option, it first attempts to
				472	read and execute commands from
				473	<A HREF="file:/etc/profile"><I>/etc/profile</I></A>
				474
				475	and
				476	<A HREF="file:~/.profile"><I>~/.profile</I></A>,
				477
				478	in that order.
				479	The
				480	<B>--noprofile</B>
				481
				482	option may be used to inhibit this behavior.
				483	When invoked as an interactive shell with the name
				484	<B>sh</B>,
				485
				486	<B>bash</B>
				487
				488	looks for the variable
				489	<FONT SIZE=-1><B>ENV</B>,
				490
				491	</FONT>
				492	expands its value if it is defined, and uses the
				493	expanded value as the name of a file to read and execute.
				494	Since a shell invoked as
				495	<B>sh</B>
				496
				497	does not attempt to read and execute commands from any other startup
				498	files, the
				499	<B>--rcfile</B>
				500
				501	option has no effect.
				502	A non-interactive shell invoked with the name
				503	<B>sh</B>
				504
				505	does not attempt to read any other startup files.
				506	When invoked as
				507	<B>sh</B>,
				508
				509	<B>bash</B>
				510
				511	enters
				512	<I>posix</I>
				513
				514	mode after the startup files are read.
				515	<P>
				516
				517	When
				518	<B>bash</B>
				519
				520	is started in
				521	<I>posix</I>
				522
				523	mode, as with the
				524	<B>--posix</B>
				525
				526	command line option, it follows the POSIX standard for startup files.
				527	In this mode, interactive shells expand the
				528	<FONT SIZE=-1><B>ENV</B>
				529
				530	</FONT>
				531	variable and commands are read and executed from the file
				532	whose name is the expanded value.
				533	No other startup files are read.
				534	<P>
				535
				536	<B>Bash</B>
				537
				538	attempts to determine when it is being run with its standard input
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	539	connected to a network connection, as when executed by the remote shell
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	540	daemon, usually <I>rshd</I>, or the secure shell daemon <I>sshd</I>.
				541	If
				542	<B>bash</B>
				543
				544	determines it is being run in this fashion, it reads and executes
				545	commands from <A HREF="file:~/.bashrc"><I>~/.bashrc</I></A>, if that file exists and is readable.
				546	It will not do this if invoked as <B>sh</B>.
				547	The
				548	<B>--norc</B>
				549
				550	option may be used to inhibit this behavior, and the
				551	<B>--rcfile</B>
				552
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	553	option may be used to force another file to be read, but neither
				554	<I>rshd</I> nor <I>sshd</I> generally invoke the shell with those options
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	555	or allow them to be specified.
				556	<P>
				557
				558	If the shell is started with the effective user (group) id not equal to the
				559	real user (group) id, and the <B>-p</B> option is not supplied, no startup
				560	files are read, shell functions are not inherited from the environment, the
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	561	<FONT SIZE=-1><B>SHELLOPTS</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	562
				563	</FONT>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	564	<FONT SIZE=-1><B>BASHOPTS</B>,
				565
				566	</FONT>
				567	<FONT SIZE=-1><B>CDPATH</B>,
				568
				569	</FONT>
				570	and
				571	<FONT SIZE=-1><B>GLOBIGNORE</B>
				572
				573	</FONT>
				574	variables, if they appear in the environment, are ignored,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	575	and the effective user id is set to the real user id.
				576	If the <B>-p</B> option is supplied at invocation, the startup behavior is
				577	the same, but the effective user id is not reset.
				578	<A NAME="lbAI"> </A>
				579	<H3>DEFINITIONS</H3>
				580
				581	<P>
				582
				583	The following definitions are used throughout the rest of this
				584	document.
				585
				586	<DL COMPACT>
				587	<DT><B>blank </B>
				588
				589	<DD>
				590	A space or tab.
				591	<DT><B>word</B>
				592
				593	<DD>
				594	A sequence of characters considered as a single unit by the shell.
				595	Also known as a
				596	<B>token</B>.
				597
				598	<DT><B>name</B>
				599
				600	<DD>
				601	A
				602	<I>word</I>
				603
				604	consisting only of alphanumeric characters and underscores, and
				605	beginning with an alphabetic character or an underscore. Also
				606	referred to as an
				607	<B>identifier</B>.
				608
				609	<DT><B>metacharacter</B>
				610
				611	<DD>
				612	A character that, when unquoted, separates words. One of the following:
				613	<BR>
				614
				615	<DL COMPACT><DT><DD>
				616	<P>
				617
				618	<B>\| & ; ( ) < > space tab</B>
				619
				620	</DL>
				621
				622	</DL>
				623	<P>
				624
				625	<DL COMPACT>
				626	<DT><B>control operator</B>
				627
				628	<DD>
				629	A <I>token</I> that performs a control function. It is one of the following
				630	symbols:
				631	<DL COMPACT><DT><DD>
				632	<P>
				633
				634	<B>\|\| & && ; ;; ( ) \| \|& <newline></B>
				635
				636	</DL>
				637
				638
				639	</DL>
				640	<A NAME="lbAJ"> </A>
				641	<H3>RESERVED WORDS</H3>
				642
				643	<I>Reserved words</I> are words that have a special meaning to the shell.
				644	The following words are recognized as reserved when unquoted and either
				645	the first word of a simple command (see
				646	<FONT SIZE=-1><B>SHELL GRAMMAR</B>
				647
				648	</FONT>
				649	below) or the third word of a
				650	<B>case </B>
				651
				652	or
				653	<B>for</B>
				654
				655	command:
				656	<DL COMPACT><DT><DD>
				657
				658	<P>
				659
				660	<B>
				661	</B>
				662
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	663	! case coproc do done elif else esac fi for function if in select then until while { } time [[ ]]
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	664	</DL>
				665
				666
				667	<A NAME="lbAK"> </A>
				668	<H3>SHELL GRAMMAR</H3>
				669
				670	<A NAME="lbAL"> </A>
				671	<H4>Simple Commands</H4>
				672
				673	<P>
				674
				675	A <I>simple command</I> is a sequence of optional variable assignments
				676	followed by <B>blank</B>-separated words and redirections, and
				677	terminated by a <I>control operator</I>. The first word
				678	specifies the command to be executed, and is passed as argument zero.
				679	The remaining words are passed as arguments to the invoked command.
				680	<P>
				681
				682	The return value of a <I>simple command</I> is its exit status, or
				683	128+<I>n</I> if the command is terminated by signal
				684	<I>n</I>.
				685
				686	<A NAME="lbAM"> </A>
				687	<H4>Pipelines</H4>
				688
				689	<P>
				690
				691	A <I>pipeline</I> is a sequence of one or more commands separated by
				692	one of the control operators
				693	<B>\|</B>
				694
				695	or <B>\|&</B>.
				696	The format for a pipeline is:
				697	<DL COMPACT><DT><DD>
				698	<P>
				699
				700	[<B>time</B> [<B>-p</B>]] [ ! ] <I>command</I> [ [<B>\|</B>\|<B>\|&</B>] <I>command2</I> ... ]
				701	</DL>
				702
				703	<P>
				704
				705	The standard output of
				706	<I>command</I>
				707
				708	is connected via a pipe to the standard input of
				709	<I>command2</I>.
				710
				711	This connection is performed before any redirections specified by the
				712	command (see
				713	<FONT SIZE=-1><B>REDIRECTION</B>
				714
				715	</FONT>
				716	below).
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	717	If <B>\|&</B> is used, <I>command</I>'s standard error, in addition to its
				718	standard output, is connected to
				719	<I>command2</I>'s standard input through the pipe;
				720	it is shorthand for <B>2>&1 \|</B>.
				721	This implicit redirection of the standard error to the standard output is
				722	performed after any redirections specified by the command.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	723	<P>
				724
				725	The return status of a pipeline is the exit status of the last
				726	command, unless the <B>pipefail</B> option is enabled.
				727	If <B>pipefail</B> is enabled, the pipeline's return status is the
				728	value of the last (rightmost) command to exit with a non-zero status,
				729	or zero if all commands exit successfully.
				730	If the reserved word
				731	<B>!</B>
				732
				733	precedes a pipeline, the exit status of that pipeline is the logical
				734	negation of the exit status as described above.
				735	The shell waits for all commands in the pipeline to
				736	terminate before returning a value.
				737	<P>
				738
				739	If the
				740	<B>time</B>
				741
				742	reserved word precedes a pipeline, the elapsed as well as user and
				743	system time consumed by its execution are reported when the pipeline
				744	terminates.
				745	The <B>-p</B> option changes the output format to that specified by POSIX.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	746	When the shell is in <I>posix mode</I>, it does not recognize
				747	<B>time</B> as a reserved word if the next token begins with a `-'.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	748	The
				749	<FONT SIZE=-1><B>TIMEFORMAT</B>
				750
				751	</FONT>
				752	variable may be set to a format string that specifies how the timing
				753	information should be displayed; see the description of
				754	<FONT SIZE=-1><B>TIMEFORMAT</B>
				755
				756	</FONT>
				757	under
				758	<B>Shell Variables</B>
				759
				760	below.
				761	<P>
				762
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	763	When the shell is in <I>posix mode</I>, <B>time</B>
				764	may be followed by a newline. In this case, the shell displays the
				765	total user and system time consumed by the shell and its children.
				766	The
				767	<FONT SIZE=-1><B>TIMEFORMAT</B>
				768
				769	</FONT>
				770	variable may be used to specify the format of
				771	the time information.
				772	<P>
				773
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	774	Each command in a pipeline is executed as a separate process (i.e., in a
				775	subshell).
				776	<A NAME="lbAN"> </A>
				777	<H4>Lists</H4>
				778
				779	<P>
				780
				781	A <I>list</I> is a sequence of one or more pipelines separated by one
				782	of the operators
				783	<B>;</B>,
				784
				785	<B>&</B>,
				786
				787	<B>&&</B>,
				788
				789	or
				790	<B>\|\|</B>,
				791
				792	and optionally terminated by one of
				793	<B>;</B>,
				794
				795	<B>&</B>,
				796
				797	or
				798	<B><newline></B>.
				799
				800	<P>
				801
				802	Of these list operators,
				803	<B>&&</B>
				804
				805	and
				806	<B>\|\|</B>
				807
				808	have equal precedence, followed by
				809	<B>;</B>
				810
				811	and
				812	<B>&</B>,
				813
				814	which have equal precedence.
				815	<P>
				816
				817	A sequence of one or more newlines may appear in a <I>list</I> instead
				818	of a semicolon to delimit commands.
				819	<P>
				820
				821	If a command is terminated by the control operator
				822	<B>&</B>,
				823
				824	the shell executes the command in the <I>background</I>
				825	in a subshell. The shell does not wait for the command to
				826	finish, and the return status is 0. Commands separated by a
				827	<B>;</B>
				828
				829	are executed sequentially; the shell waits for each
				830	command to terminate in turn. The return status is the
				831	exit status of the last command executed.
				832	<P>
				833
				834	AND and OR lists are sequences of one of more pipelines separated by the
				835	<B>&&</B> and <B>\|\|</B> control operators, respectively.
				836	AND and OR lists are executed with left associativity.
				837	An AND list has the form
				838	<DL COMPACT><DT><DD>
				839	<P>
				840
				841	<I>command1</I> <B>&&</B> <I>command2</I>
				842	</DL>
				843
				844	<P>
				845
				846	<I>command2</I>
				847
				848	is executed if, and only if,
				849	<I>command1</I>
				850
				851	returns an exit status of zero.
				852	<P>
				853
				854	An OR list has the form
				855	<DL COMPACT><DT><DD>
				856	<P>
				857
				858	<I>command1</I> <B>\|\|</B> <I>command2</I>
				859	<P>
				860
				861	</DL>
				862
				863	<P>
				864
				865	<I>command2</I>
				866
				867	is executed if and only if
				868	<I>command1</I>
				869
				870	returns a non-zero exit status.
				871	The return status of
				872	AND and OR lists is the exit status of the last command
				873	executed in the list.
				874	<A NAME="lbAO"> </A>
				875	<H4>Compound Commands</H4>
				876
				877	<P>
				878
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	879	A <I>compound command</I> is one of the following.
				880	In most cases a <I>list</I> in a command's description may be separated from
				881	the rest of the command by one or more newlines, and may be followed by a
				882	newline in place of a semicolon.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	883	<DL COMPACT>
				884	<DT>(<I>list</I>)<DD>
				885	<I>list</I> is executed in a subshell environment (see
				886	<FONT SIZE=-1><B>COMMAND EXECUTION ENVIRONMENT</B></FONT>
				887	below).
				888	Variable assignments and builtin
				889	commands that affect the shell's environment do not remain in effect
				890	after the command completes. The return status is the exit status of
				891	<I>list</I>.
				892	<DT>{ <I>list</I>; }<DD>
				893	<I>list</I> is simply executed in the current shell environment.
				894	<I>list</I> must be terminated with a newline or semicolon.
				895	This is known as a <I>group command</I>.
				896	The return status is the exit status of
				897	<I>list</I>.
				898	Note that unlike the metacharacters <B>(</B> and <B>)</B>, <B>{</B> and
				899	<B>}</B> are <I>reserved words</I> and must occur where a reserved
				900	word is permitted to be recognized. Since they do not cause a word
				901	break, they must be separated from <I>list</I> by whitespace or another
				902	shell metacharacter.
				903	<DT>((<I>expression</I>))<DD>
				904	The <I>expression</I> is evaluated according to the rules described
				905	below under
				906	<FONT SIZE=-1><B>ARITHMETIC EVALUATION</B>.
				907
				908	</FONT>
				909	If the value of the expression is non-zero, the return status is 0;
				910	otherwise the return status is 1. This is exactly equivalent to
				911	<B>let "</B><I>expression</I>".
				912	<DT><B>[[</B> <I>expression</I> <B>]]</B><DD>
				913	Return a status of 0 or 1 depending on the evaluation of
				914	the conditional expression <I>expression</I>.
				915	Expressions are composed of the primaries described below under
				916	<FONT SIZE=-1><B>CONDITIONAL EXPRESSIONS</B>.
				917
				918	</FONT>
				919	Word splitting and pathname expansion are not performed on the words
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	920	between the <B>[[</B> and <B>]]</B>; tilde expansion,
				921	parameter and variable expansion,
				922	arithmetic expansion, command substitution, process
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	923	substitution, and quote removal are performed.
				924	Conditional operators such as <B>-f</B> must be unquoted to be recognized
				925	as primaries.
				926	<P>
				927
				928
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	929	When used with <B>[[</B>, the <B><</B> and <B>></B> operators sort
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	930	lexicographically using the current locale.
				931	<P>
				932
				933
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	934	When the <B>==</B> and <B>!=</B> operators are used, the string to the
				935	right of the operator is considered a pattern and matched according
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	936	to the rules described below under <B>Pattern Matching</B>,
				937	as if the <B>extglob</B> shell option were enabled.
				938	The <B>=</B> operator is equivalent to <B>==</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	939	If the shell option
				940	<B>nocasematch</B>
				941
				942	is enabled, the match is performed without regard to the case
				943	of alphabetic characters.
				944	The return value is 0 if the string matches (<B>==</B>) or does not match
				945	(<B>!=</B>) the pattern, and 1 otherwise.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	946	Any part of the pattern may be quoted to force the quoted portion
				947	to be matched as a string.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	948	<P>
				949
				950
				951	An additional binary operator, <B>=~</B>, is available, with the same
				952	precedence as <B>==</B> and <B>!=</B>.
				953	When it is used, the string to the right of the operator is considered
				954	an extended regular expression and matched accordingly (as in <I>regex</I>(3)).
				955	The return value is 0 if the string matches
				956	the pattern, and 1 otherwise.
				957	If the regular expression is syntactically incorrect, the conditional
				958	expression's return value is 2.
				959	If the shell option
				960	<B>nocasematch</B>
				961
				962	is enabled, the match is performed without regard to the case
				963	of alphabetic characters.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	964	Any part of the pattern may be quoted to force the quoted portion
				965	to be matched as a string.
				966	Bracket expressions in regular expressions must be treated carefully,
				967	since normal quoting characters lose their meanings between brackets.
				968	If the pattern is stored in a shell variable, quoting the variable
				969	expansion forces the entire pattern to be matched as a string.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	970	Substrings matched by parenthesized subexpressions within the regular
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	971	expression are saved in the array variable
				972	<FONT SIZE=-1><B>BASH_REMATCH</B>.
				973
				974	</FONT>
				975	The element of
				976	<FONT SIZE=-1><B>BASH_REMATCH</B>
				977
				978	</FONT>
				979	with index 0 is the portion of the string
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	980	matching the entire regular expression.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	981	The element of
				982	<FONT SIZE=-1><B>BASH_REMATCH</B>
				983
				984	</FONT>
				985	with index <I>n</I> is the portion of the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	986	string matching the <I>n</I>th parenthesized subexpression.
				987	<P>
				988
				989
				990	Expressions may be combined using the following operators, listed
				991	in decreasing order of precedence:
				992	<P>
				993
				994
				995	<DL COMPACT><DT><DD>
				996
				997	<DL COMPACT>
				998	<DT><B>( </B><I>expression</I> )
				999
				1000	<DD>
				1001	Returns the value of <I>expression</I>.
				1002	This may be used to override the normal precedence of operators.
				1003	<DT><B>! </B><I>expression</I>
				1004
				1005	<DD>
				1006	True if
				1007	<I>expression</I>
				1008
				1009	is false.
				1010	<DT><I>expression1</I> <B>&&</B> <I>expression2</I><DD>
				1011	True if both
				1012	<I>expression1</I>
				1013
				1014	and
				1015	<I>expression2</I>
				1016
				1017	are true.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1018	<DT><I>expression1</I> <B>\|\|</B> <I>expression2</I><DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1019	True if either
				1020	<I>expression1</I>
				1021
				1022	or
				1023	<I>expression2</I>
				1024
				1025	is true.
				1026
				1027	</DL>
				1028	<P>
				1029
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1030	The <B>&&</B> and <B>\|\|</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1031	operators do not evaluate <I>expression2</I> if the value of
				1032	<I>expression1</I> is sufficient to determine the return value of
				1033	the entire conditional expression.
				1034	</DL>
				1035
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1036	<DT><B>for</B> <I>name</I> [ [ <B>in</B> [ <I>word ...</I> ] ] ; ] <B>do</B> <I>list</I> ; <B>done</B><DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1037	The list of words following <B>in</B> is expanded, generating a list
				1038	of items.
				1039	The variable <I>name</I> is set to each element of this list
				1040	in turn, and <I>list</I> is executed each time.
				1041	If the <B>in</B> <I>word</I> is omitted, the <B>for</B> command executes
				1042	<I>list</I> once for each positional parameter that is set (see
				1043	<FONT SIZE=-1><B>PARAMETERS</B>
				1044
				1045	</FONT>
				1046	below).
				1047	The return status is the exit status of the last command that executes.
				1048	If the expansion of the items following <B>in</B> results in an empty
				1049	list, no commands are executed, and the return status is 0.
				1050	<DT><B>for</B> (( <I>expr1</I> ; <I>expr2</I> ; <I>expr3</I> )) ; <B>do</B> <I>list</I> ; <B>done</B><DD>
				1051	First, the arithmetic expression <I>expr1</I> is evaluated according
				1052	to the rules described below under
				1053	<FONT SIZE=-1><B>ARITHMETIC EVALUATION</B>.
				1054
				1055	</FONT>
				1056	The arithmetic expression <I>expr2</I> is then evaluated repeatedly
				1057	until it evaluates to zero.
				1058	Each time <I>expr2</I> evaluates to a non-zero value, <I>list</I> is
				1059	executed and the arithmetic expression <I>expr3</I> is evaluated.
				1060	If any expression is omitted, it behaves as if it evaluates to 1.
				1061	The return value is the exit status of the last command in <I>list</I>
				1062	that is executed, or false if any of the expressions is invalid.
				1063	<DT><B>select</B> <I>name</I> [ <B>in</B> <I>word</I> ] ; <B>do</B> <I>list</I> ; <B>done</B><DD>
				1064	The list of words following <B>in</B> is expanded, generating a list
				1065	of items. The set of expanded words is printed on the standard
				1066	error, each preceded by a number. If the <B>in</B>
				1067	<I>word</I> is omitted, the positional parameters are printed (see
				1068	<FONT SIZE=-1><B>PARAMETERS</B>
				1069
				1070	</FONT>
				1071	below). The
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1072	<FONT SIZE=-1><B>PS3</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1073
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1074	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1075	prompt is then displayed and a line read from the standard input.
				1076	If the line consists of a number corresponding to one of
				1077	the displayed words, then the value of
				1078	<I>name</I>
				1079
				1080	is set to that word. If the line is empty, the words and prompt
				1081	are displayed again. If EOF is read, the command completes. Any
				1082	other value read causes
				1083	<I>name</I>
				1084
				1085	to be set to null. The line read is saved in the variable
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1086	<FONT SIZE=-1><B>REPLY</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1087
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1088	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1089	The
				1090	<I>list</I>
				1091
				1092	is executed after each selection until a
				1093	<B>break</B>
				1094
				1095	command is executed.
				1096	The exit status of
				1097	<B>select</B>
				1098
				1099	is the exit status of the last command executed in
				1100	<I>list</I>,
				1101
				1102	or zero if no commands were executed.
				1103	<DT><B>case</B> <I>word</I> <B>in</B> [ [(] <I>pattern</I> [ <B>\|</B> <I>pattern</I> ]
				1104	<DD>
				1105	A <B>case</B> command first expands <I>word</I>, and tries to match
				1106	it against each <I>pattern</I> in turn, using the same matching rules
				1107	as for pathname expansion (see
				1108	<B>Pathname Expansion</B>
				1109
				1110	below).
				1111	The <I>word</I> is expanded using tilde
				1112	expansion, parameter and variable expansion, arithmetic substitution,
				1113	command substitution, process substitution and quote removal.
				1114	Each <I>pattern</I> examined is expanded using tilde
				1115	expansion, parameter and variable expansion, arithmetic substitution,
				1116	command substitution, and process substitution.
				1117	If the shell option
				1118	<B>nocasematch</B>
				1119
				1120	is enabled, the match is performed without regard to the case
				1121	of alphabetic characters.
				1122	When a match is found, the corresponding <I>list</I> is executed.
				1123	If the <B>;;</B> operator is used, no subsequent matches are attempted after
				1124	the first pattern match.
				1125	Using <B>;&</B> in place of <B>;;</B> causes execution to continue with
				1126	the <I>list</I> associated with the next set of patterns.
				1127	Using <B>;;&</B> in place of <B>;;</B> causes the shell to test the next
				1128	pattern list in the statement, if any, and execute any associated <I>list</I>
				1129	on a successful match.
				1130	The exit status is zero if no
				1131	pattern matches. Otherwise, it is the exit status of the
				1132	last command executed in <I>list</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1133	<DT><B>if</B> <I>list</I>; <B>then</B> <I>list</I>; [ <B>elif</B> <I>list</I>; <B>then</B> <I>list</I>; ] ... [ <B>else</B> <I>list</I>; ] <B>fi</B><DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1134	The
				1135	<B>if </B>
				1136
				1137	<I>list</I>
				1138
				1139	is executed. If its exit status is zero, the
				1140	<B>then</B> <I>list</I> is executed. Otherwise, each <B>elif</B>
				1141	<I>list</I> is executed in turn, and if its exit status is zero,
				1142	the corresponding <B>then</B> <I>list</I> is executed and the
				1143	command completes. Otherwise, the <B>else</B> <I>list</I> is
				1144	executed, if present. The exit status is the exit status of the
				1145	last command executed, or zero if no condition tested true.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1146	<DT><B>while</B> <I>list-1</I>; <B>do</B> <I>list-2</I>; <B>done</B><DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1147
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1148	<DT><B>until</B> <I>list-1</I>; <B>do</B> <I>list-2</I>; <B>done</B><DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1149
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1150	The <B>while</B> command continuously executes the list
				1151	<I>list-2</I> as long as the last command in the list <I>list-1</I> returns
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1152	an exit status of zero. The <B>until</B> command is identical
				1153	to the <B>while</B> command, except that the test is negated;
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1154	<I>list-2</I>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1155
				1156	is executed as long as the last command in
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1157	<I>list-1</I>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1158
				1159	returns a non-zero exit status.
				1160	The exit status of the <B>while</B> and <B>until</B> commands
				1161	is the exit status
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1162	of the last command executed in <I>list-2</I>, or zero if
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1163	none was executed.
				1164	</DL>
				1165	<A NAME="lbAP"> </A>
				1166	<H4>Coprocesses</H4>
				1167
				1168	<P>
				1169
				1170	A <I>coprocess</I> is a shell command preceded by the <B>coproc</B> reserved
				1171	word.
				1172	A coprocess is executed asynchronously in a subshell, as if the command
				1173	had been terminated with the <B>&</B> control operator, with a two-way pipe
				1174	established between the executing shell and the coprocess.
				1175	<P>
				1176
				1177	The format for a coprocess is:
				1178	<DL COMPACT><DT><DD>
				1179	<P>
				1180
				1181	<B>coproc</B> [<I>NAME</I>] <I>command</I> [<I>redirections</I>]
				1182	</DL>
				1183
				1184	<P>
				1185
				1186	This creates a coprocess named <I>NAME</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1187	If <I>NAME</I> is not supplied, the default name is <B>COPROC</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1188	<I>NAME</I> must not be supplied if <I>command</I> is a <I>simple
				1189	command</I> (see above); otherwise, it is interpreted as the first word
				1190	of the simple command.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1191	When the coprocess is executed, the shell creates an array variable (see
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1192	<B>Arrays</B>
				1193
				1194	below) named <I>NAME</I> in the context of the executing shell.
				1195	The standard output of
				1196	<I>command</I>
				1197
				1198	is connected via a pipe to a file descriptor in the executing shell,
				1199	and that file descriptor is assigned to <I>NAME</I>[0].
				1200	The standard input of
				1201	<I>command</I>
				1202
				1203	is connected via a pipe to a file descriptor in the executing shell,
				1204	and that file descriptor is assigned to <I>NAME</I>[1].
				1205	This pipe is established before any redirections specified by the
				1206	command (see
				1207	<FONT SIZE=-1><B>REDIRECTION</B>
				1208
				1209	</FONT>
				1210	below).
				1211	The file descriptors can be utilized as arguments to shell commands
				1212	and redirections using standard word expansions.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1213	The file descriptors are not available in subshells.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1214	The process ID of the shell spawned to execute the coprocess is
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1215	available as the value of the variable <I>NAME</I>_PID.
				1216	The <B>wait</B>
				1217	builtin command may be used to wait for the coprocess to terminate.
				1218	<P>
				1219
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1220	Since the coprocess is created as an asynchronous command,
				1221	the <B>coproc</B> command always returns success.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1222	The return status of a coprocess is the exit status of <I>command</I>.
				1223	<A NAME="lbAQ"> </A>
				1224	<H4>Shell Function Definitions</H4>
				1225
				1226	<P>
				1227
				1228	A shell function is an object that is called like a simple command and
				1229	executes a compound command with a new set of positional parameters.
				1230	Shell functions are declared as follows:
				1231	<DL COMPACT>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1232	<DT><I>name</I> () <I>compound-command</I> [<I>redirection</I>]<DD>
				1233
				1234	<DT><B>function</B> <I>name</I> [()] <I>compound-command</I> [<I>redirection</I>]<DD>
				1235
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1236	This defines a function named <I>name</I>.
				1237	The reserved word <B>function</B> is optional.
				1238	If the <B>function</B> reserved word is supplied, the parentheses are optional.
				1239	The <I>body</I> of the function is the compound command
				1240	<I>compound-command </I>
				1241
				1242	(see <B>Compound Commands</B> above).
				1243	That command is usually a <I>list</I> of commands between { and }, but
				1244	may be any command listed under <B>Compound Commands</B> above.
				1245	<I>compound-command</I> is executed whenever <I>name</I> is specified as the
				1246	name of a simple command.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1247	When in <I>posix mode</I>, <I>name</I> may not be the name of one of the
				1248	POSIX <I>special builtins</I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1249	Any redirections (see
				1250	<FONT SIZE=-1><B>REDIRECTION</B>
				1251
				1252	</FONT>
				1253	below) specified when a function is defined are performed
				1254	when the function is executed.
				1255	The exit status of a function definition is zero unless a syntax error
				1256	occurs or a readonly function with the same name already exists.
				1257	When executed, the exit status of a function is the exit status of the
				1258	last command executed in the body. (See
				1259	<FONT SIZE=-1><B>FUNCTIONS</B>
				1260
				1261	</FONT>
				1262	below.)
				1263	</DL>
				1264	<A NAME="lbAR"> </A>
				1265	<H3>COMMENTS</H3>
				1266
				1267	In a non-interactive shell, or an interactive shell in which the
				1268	<B>interactive_comments</B>
				1269
				1270	option to the
				1271	<B>shopt</B>
				1272
				1273	builtin is enabled (see
				1274	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				1275
				1276	</FONT>
				1277	below), a word beginning with
				1278	<B>#</B>
				1279
				1280	causes that word and all remaining characters on that line to
				1281	be ignored. An interactive shell without the
				1282	<B>interactive_comments</B>
				1283
				1284	option enabled does not allow comments. The
				1285	<B>interactive_comments</B>
				1286
				1287	option is on by default in interactive shells.
				1288	<A NAME="lbAS"> </A>
				1289	<H3>QUOTING</H3>
				1290
				1291	<I>Quoting</I> is used to remove the special meaning of certain
				1292	characters or words to the shell. Quoting can be used to
				1293	disable special treatment for special characters, to prevent
				1294	reserved words from being recognized as such, and to prevent
				1295	parameter expansion.
				1296	<P>
				1297
				1298	Each of the <I>metacharacters</I> listed above under
				1299	<FONT SIZE=-1><B>DEFINITIONS</B>
				1300
				1301	</FONT>
				1302	has special meaning to the shell and must be quoted if it is to
				1303	represent itself.
				1304	<P>
				1305
				1306	When the command history expansion facilities are being used
				1307	(see
				1308	<FONT SIZE=-1><B>HISTORY EXPANSION</B>
				1309
				1310	</FONT>
				1311	below), the
				1312	<I>history expansion</I> character, usually <B>!</B>, must be quoted
				1313	to prevent history expansion.
				1314	<P>
				1315
				1316	There are three quoting mechanisms: the
				1317	<I>escape character</I>,
				1318
				1319	single quotes, and double quotes.
				1320	<P>
				1321
				1322	A non-quoted backslash (<B>\</B>) is the
				1323	<I>escape character</I>.
				1324
				1325	It preserves the literal value of the next character that follows,
				1326	with the exception of <newline>. If a <B>\</B><newline> pair
				1327	appears, and the backslash is not itself quoted, the <B>\</B><newline>
				1328	is treated as a line continuation (that is, it is removed from the
				1329	input stream and effectively ignored).
				1330	<P>
				1331
				1332	Enclosing characters in single quotes preserves the literal value
				1333	of each character within the quotes. A single quote may not occur
				1334	between single quotes, even when preceded by a backslash.
				1335	<P>
				1336
				1337	Enclosing characters in double quotes preserves the literal value
				1338	of all characters within the quotes, with the exception of
				1339	<B>$</B>,
				1340
				1341	<B>`</B>,
				1342
				1343	<B>\</B>,
				1344
				1345	and, when history expansion is enabled,
				1346	<B>!</B>.
				1347
				1348	The characters
				1349	<B>$</B>
				1350
				1351	and
				1352	<B>`</B>
				1353
				1354	retain their special meaning within double quotes. The backslash
				1355	retains its special meaning only when followed by one of the following
				1356	characters:
				1357	<B>$</B>,
				1358
				1359	<B>`</B>,
				1360
				1361	<B>"</B>,
				1362	<B>\</B>,
				1363
				1364	or
				1365	<B><newline></B>.
				1366
				1367	A double quote may be quoted within double quotes by preceding it with
				1368	a backslash.
				1369	If enabled, history expansion will be performed unless an
				1370	<B>!</B>
				1371
				1372	appearing in double quotes is escaped using a backslash.
				1373	The backslash preceding the
				1374	<B>!</B>
				1375
				1376	is not removed.
				1377	<P>
				1378
				1379	The special parameters
				1380	<B>*</B>
				1381
				1382	and
				1383	<B>@</B>
				1384
				1385	have special meaning when in double
				1386	quotes (see
				1387	<FONT SIZE=-1><B>PARAMETERS</B>
				1388
				1389	</FONT>
				1390	below).
				1391	<P>
				1392
				1393	Words of the form <B>$</B>aq<I>string</I>aq are treated specially. The
				1394	word expands to <I>string</I>, with backslash-escaped characters replaced
				1395	as specified by the ANSI C standard. Backslash escape sequences, if
				1396	present, are decoded as follows:
				1397	<DL COMPACT><DT><DD>
				1398
				1399	<DL COMPACT>
				1400	<DT><B>\a</B>
				1401
				1402	<DD>
				1403	alert (bell)
				1404	<DT><B>\b</B>
				1405
				1406	<DD>
				1407	backspace
				1408	<DT><B>\e</B>
				1409
				1410	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1411	<DT><B>\E</B>
				1412
				1413	<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1414	an escape character
				1415	<DT><B>\f</B>
				1416
				1417	<DD>
				1418	form feed
				1419	<DT><B>\n</B>
				1420
				1421	<DD>
				1422	new line
				1423	<DT><B>\r</B>
				1424
				1425	<DD>
				1426	carriage return
				1427	<DT><B>\t</B>
				1428
				1429	<DD>
				1430	horizontal tab
				1431	<DT><B>\v</B>
				1432
				1433	<DD>
				1434	vertical tab
				1435	<DT><B>\\</B>
				1436
				1437	<DD>
				1438	backslash
				1439	<DT><B>\aq</B>
				1440
				1441	<DD>
				1442	single quote
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1443	<DT><B>\dq</B>
				1444
				1445	<DD>
				1446	double quote
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1447	<DT><B>\</B><I>nnn</I>
				1448
				1449	<DD>
				1450	the eight-bit character whose value is the octal value <I>nnn</I>
				1451	(one to three digits)
				1452	<DT><B>\x</B><I>HH</I>
				1453
				1454	<DD>
				1455	the eight-bit character whose value is the hexadecimal value <I>HH</I>
				1456	(one or two hex digits)
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1457	<DT><B>\u</B><I>HHHH</I>
				1458
				1459	<DD>
				1460	the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
				1461	<I>HHHH</I> (one to four hex digits)
				1462	<DT><B>\U</B><I>HHHHHHHH</I>
				1463
				1464	<DD>
				1465	the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
				1466	<I>HHHHHHHH</I> (one to eight hex digits)
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1467	<DT><B>\c</B><I>x</I>
				1468
				1469	<DD>
				1470	a control-<I>x</I> character
				1471
				1472	</DL></DL>
				1473
				1474	<P>
				1475
				1476	The expanded result is single-quoted, as if the dollar sign had
				1477	not been present.
				1478	<P>
				1479
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1480	A double-quoted string preceded by a dollar sign (<B>$</B>dq<I>string</I>dq)
				1481	will cause the string to be translated according to the current locale.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1482	If the current locale is <B>C</B> or <B>POSIX</B>, the dollar sign
				1483	is ignored.
				1484	If the string is translated and replaced, the replacement is
				1485	double-quoted.
				1486	<A NAME="lbAT"> </A>
				1487	<H3>PARAMETERS</H3>
				1488
				1489	A
				1490	<I>parameter</I>
				1491
				1492	is an entity that stores values.
				1493	It can be a
				1494	<I>name</I>,
				1495
				1496	a number, or one of the special characters listed below under
				1497	<B>Special Parameters</B>.
				1498
				1499	A
				1500	<I>variable</I>
				1501
				1502	is a parameter denoted by a
				1503	<I>name</I>.
				1504
				1505	A variable has a <I>value</I> and zero or more <I>attributes</I>.
				1506	Attributes are assigned using the
				1507	<B>declare</B>
				1508
				1509	builtin command (see
				1510	<B>declare</B>
				1511
				1512	below in
				1513	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>).
				1514
				1515	</FONT>
				1516	<P>
				1517
				1518	A parameter is set if it has been assigned a value. The null string is
				1519	a valid value. Once a variable is set, it may be unset only by using
				1520	the
				1521	<B>unset</B>
				1522
				1523	builtin command (see
				1524	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				1525
				1526	</FONT>
				1527	below).
				1528	<P>
				1529
				1530	A
				1531	<I>variable</I>
				1532
				1533	may be assigned to by a statement of the form
				1534	<DL COMPACT><DT><DD>
				1535	<P>
				1536
				1537	<I>name</I>=[<I>value</I>]
				1538	</DL>
				1539
				1540	<P>
				1541
				1542	If
				1543	<I>value</I>
				1544
				1545	is not given, the variable is assigned the null string. All
				1546	<I>values</I>
				1547
				1548	undergo tilde expansion, parameter and variable expansion,
				1549	command substitution, arithmetic expansion, and quote
				1550	removal (see
				1551	<FONT SIZE=-1><B>EXPANSION</B>
				1552
				1553	</FONT>
				1554	below). If the variable has its
				1555	<B>integer</B>
				1556
				1557	attribute set, then
				1558	<I>value</I>
				1559
				1560	is evaluated as an arithmetic expression even if the $((...)) expansion is
				1561	not used (see
				1562	<B>Arithmetic Expansion</B>
				1563
				1564	below).
				1565	Word splitting is not performed, with the exception
				1566	of <B>"$@"</B> as explained below under
				1567	<B>Special Parameters</B>.
				1568
				1569	Pathname expansion is not performed.
				1570	Assignment statements may also appear as arguments to the
				1571	<B>alias</B>,
				1572
				1573	<B>declare</B>,
				1574
				1575	<B>typeset</B>,
				1576
				1577	<B>export</B>,
				1578
				1579	<B>readonly</B>,
				1580
				1581	and
				1582	<B>local</B>
				1583
				1584	builtin commands.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1585	When in <I>posix mode</I>, these builtins may appear in a command after
				1586	one or more instances of the <B>command</B> builtin and retain these
				1587	assignment statement properties.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1588	<P>
				1589
				1590	In the context where an assignment statement is assigning a value
				1591	to a shell variable or array index, the += operator can be used to
				1592	append to or add to the variable's previous value.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1593	When += is applied to a variable for which the <I>integer</I> attribute has been
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1594	set, <I>value</I> is evaluated as an arithmetic expression and added to the
				1595	variable's current value, which is also evaluated.
				1596	When += is applied to an array variable using compound assignment (see
				1597	<B>Arrays</B>
				1598
				1599	below), the
				1600	variable's value is not unset (as it is when using =), and new values are
				1601	appended to the array beginning at one greater than the array's maximum index
				1602	(for indexed arrays) or added as additional key-value pairs in an
				1603	associative array.
				1604	When applied to a string-valued variable, <I>value</I> is expanded and
				1605	appended to the variable's value.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1606	<P>
				1607
				1608	A variable can be assigned the <I>nameref</I> attribute using the
				1609	<B>-n</B> option to the <B>declare</B> or <B>local</B> builtin commands
				1610	(see the descriptions of <B>declare</B> and <B>local</B> below)
				1611	to create a <I>nameref</I>, or a reference to another variable.
				1612	This allows variables to be manipulated indirectly.
				1613	Whenever the nameref variable is referenced or assigned to, the operation
				1614	is actually performed on the variable specified by the nameref variable's
				1615	value.
				1616	A nameref is commonly used within shell functions to refer to a variable
				1617	whose name is passed as an argument to the function.
				1618	For instance, if a variable name is passed to a shell function as its first
				1619	argument, running
				1620	<P>
				1621	<DL COMPACT><DT><DD>
				1622	<TT>declare -n ref=$1</TT>
				1623
				1624	</DL>
				1625
				1626	<P>
				1627	inside the function creates a nameref variable <B>ref</B> whose value is
				1628	the variable name passed as the first argument.
				1629	References and assignments to <B>ref</B> are treated as references and
				1630	assignments to the variable whose name was passed as <B>$1</B>.
				1631	If the control variable in a <B>for</B> loop has the nameref attribute,
				1632	the list of words can be a list of shell variables, and a name reference
				1633	will be established for each word in the list, in turn, when the loop is
				1634	executed.
				1635	Array variables cannot be given the <B>-n</B> attribute.
				1636	However, nameref variables can reference array variables and subscripted
				1637	array variables.
				1638	Namerefs can be unset using the <B>-n</B> option to the <B>unset</B> builtin.
				1639	Otherwise, if <B>unset</B> is executed with the name of a nameref variable
				1640	as an argument, the variable referenced by the nameref variable will be unset.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1641	<A NAME="lbAU"> </A>
				1642	<H4>Positional Parameters</H4>
				1643
				1644	<P>
				1645
				1646	A
				1647	<I>positional parameter</I>
				1648
				1649	is a parameter denoted by one or more
				1650	digits, other than the single digit 0. Positional parameters are
				1651	assigned from the shell's arguments when it is invoked,
				1652	and may be reassigned using the
				1653	<B>set</B>
				1654
				1655	builtin command. Positional parameters may not be assigned to
				1656	with assignment statements. The positional parameters are
				1657	temporarily replaced when a shell function is executed (see
				1658	<FONT SIZE=-1><B>FUNCTIONS</B>
				1659
				1660	</FONT>
				1661	below).
				1662	<P>
				1663
				1664	When a positional parameter consisting of more than a single
				1665	digit is expanded, it must be enclosed in braces (see
				1666	<FONT SIZE=-1><B>EXPANSION</B>
				1667
				1668	</FONT>
				1669	below).
				1670	<A NAME="lbAV"> </A>
				1671	<H4>Special Parameters</H4>
				1672
				1673	<P>
				1674
				1675	The shell treats several parameters specially. These parameters may
				1676	only be referenced; assignment to them is not allowed.
				1677
				1678	<DL COMPACT>
				1679	<DT><B>*</B>
				1680
				1681	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1682	Expands to the positional parameters, starting from one.
				1683	When the expansion is not within double quotes, each positional parameter
				1684	expands to a separate word.
				1685	In contexts where it is performed, those words
				1686	are subject to further word splitting and pathname expansion.
				1687	When the expansion occurs within double quotes, it expands to a single word
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1688	with the value of each parameter separated by the first character
				1689	of the
				1690	<FONT SIZE=-1><B>IFS</B>
				1691
				1692	</FONT>
				1693	special variable. That is, "<B>$*</B>" is equivalent
				1694	to "<B>$1</B><I>c</I><B>$2</B><I>c</I><B>...</B>", where
				1695	<I>c</I>
				1696
				1697	is the first character of the value of the
				1698	<FONT SIZE=-1><B>IFS</B>
				1699
				1700	</FONT>
				1701	variable. If
				1702	<FONT SIZE=-1><B>IFS</B>
				1703
				1704	</FONT>
				1705	is unset, the parameters are separated by spaces.
				1706	If
				1707	<FONT SIZE=-1><B>IFS</B>
				1708
				1709	</FONT>
				1710	is null, the parameters are joined without intervening separators.
				1711	<DT><B>@</B>
				1712
				1713	<DD>
				1714	Expands to the positional parameters, starting from one. When the
				1715	expansion occurs within double quotes, each parameter expands to a
				1716	separate word. That is, "<B>$@</B>" is equivalent to
				1717	"<B>$1</B>" "<B>$2</B>" ...
				1718	If the double-quoted expansion occurs within a word, the expansion of
				1719	the first parameter is joined with the beginning part of the original
				1720	word, and the expansion of the last parameter is joined with the last
				1721	part of the original word.
				1722	When there are no positional parameters, "<B>$@</B>" and
				1723	<B>$@</B>
				1724
				1725	expand to nothing (i.e., they are removed).
				1726	<DT><B>#</B>
				1727
				1728	<DD>
				1729	Expands to the number of positional parameters in decimal.
				1730	<DT><B>?</B>
				1731
				1732	<DD>
				1733	Expands to the exit status of the most recently executed foreground
				1734	pipeline.
				1735	<DT><B>-</B>
				1736
				1737	<DD>
				1738	Expands to the current option flags as specified upon invocation,
				1739	by the
				1740	<B>set</B>
				1741
				1742	builtin command, or those set by the shell itself
				1743	(such as the
				1744	<B>-i</B>
				1745
				1746	option).
				1747	<DT><B>$</B>
				1748
				1749	<DD>
				1750	Expands to the process ID of the shell. In a () subshell, it
				1751	expands to the process ID of the current shell, not the
				1752	subshell.
				1753	<DT><B>!</B>
				1754
				1755	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1756	Expands to the process ID of the job most recently placed into the
				1757	background, whether executed as an asynchronous command or using
				1758	the <B>bg</B> builtin (see
				1759	<FONT SIZE=-1><B>JOB CONTROL</B>
				1760
				1761	</FONT>
				1762	below).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1763	<DT><B>0</B>
				1764
				1765	<DD>
				1766	Expands to the name of the shell or shell script. This is set at
				1767	shell initialization. If
				1768	<B>bash</B>
				1769
				1770	is invoked with a file of commands,
				1771	<B>$0</B>
				1772
				1773	is set to the name of that file. If
				1774	<B>bash</B>
				1775
				1776	is started with the
				1777	<B>-c</B>
				1778
				1779	option, then
				1780	<B>$0</B>
				1781
				1782	is set to the first argument after the string to be
				1783	executed, if one is present. Otherwise, it is set
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1784	to the filename used to invoke
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1785	<B>bash</B>,
				1786
				1787	as given by argument zero.
				1788	<DT><B>_</B>
				1789
				1790	<DD>
				1791	At shell startup, set to the absolute pathname used to invoke the
				1792	shell or shell script being executed as passed in the environment
				1793	or argument list.
				1794	Subsequently, expands to the last argument to the previous command,
				1795	after expansion.
				1796	Also set to the full pathname used to invoke each command executed
				1797	and placed in the environment exported to that command.
				1798	When checking mail, this parameter holds the name of the mail file
				1799	currently being checked.
				1800
				1801	</DL>
				1802	<A NAME="lbAW"> </A>
				1803	<H4>Shell Variables</H4>
				1804
				1805	<P>
				1806
				1807	The following variables are set by the shell:
				1808	<P>
				1809
				1810
				1811	<DL COMPACT>
				1812	<DT><B>BASH</B>
				1813
				1814	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1815	Expands to the full filename used to invoke this instance of
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1816	<B>bash</B>.
				1817
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1818	<DT><B>BASHOPTS</B>
				1819
				1820	<DD>
				1821	A colon-separated list of enabled shell options. Each word in
				1822	the list is a valid argument for the
				1823	<B>-s</B>
				1824
				1825	option to the
				1826	<B>shopt</B>
				1827
				1828	builtin command (see
				1829	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				1830
				1831	</FONT>
				1832	below). The options appearing in
				1833	<FONT SIZE=-1><B>BASHOPTS</B>
				1834
				1835	</FONT>
				1836	are those reported as
				1837	<I>on</I>
				1838
				1839	by <B>shopt</B>.
				1840	If this variable is in the environment when
				1841	<B>bash</B>
				1842
				1843	starts up, each shell option in the list will be enabled before
				1844	reading any startup files.
				1845	This variable is read-only.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1846	<DT><B>BASHPID</B>
				1847
				1848	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1849	Expands to the process ID of the current <B>bash</B> process.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1850	This differs from <B>$$</B> under certain circumstances, such as subshells
				1851	that do not require <B>bash</B> to be re-initialized.
				1852	<DT><B>BASH_ALIASES</B>
				1853
				1854	<DD>
				1855	An associative array variable whose members correspond to the internal
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1856	list of aliases as maintained by the <B>alias</B> builtin.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1857	Elements added to this array appear in the alias list; unsetting array
				1858	elements cause aliases to be removed from the alias list.
				1859	<DT><B>BASH_ARGC</B>
				1860
				1861	<DD>
				1862	An array variable whose values are the number of parameters in each
				1863	frame of the current <B>bash</B> execution call stack.
				1864	The number of
				1865	parameters to the current subroutine (shell function or script executed
				1866	with <B>.</B> or <B>source</B>) is at the top of the stack.
				1867	When a subroutine is executed, the number of parameters passed is pushed onto
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1868	<FONT SIZE=-1><B>BASH_ARGC</B>.
				1869
				1870	</FONT>
				1871	The shell sets
				1872	<FONT SIZE=-1><B>BASH_ARGC</B>
				1873
				1874	</FONT>
				1875	only when in extended debugging mode (see the description of the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1876	<B>extdebug</B>
				1877
				1878	option to the
				1879	<B>shopt</B>
				1880
				1881	builtin below)
				1882	<DT><B>BASH_ARGV</B>
				1883
				1884	<DD>
				1885	An array variable containing all of the parameters in the current <B>bash</B>
				1886	execution call stack. The final parameter of the last subroutine call
				1887	is at the top of the stack; the first parameter of the initial call is
				1888	at the bottom. When a subroutine is executed, the parameters supplied
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1889	are pushed onto
				1890	<FONT SIZE=-1><B>BASH_ARGV</B>.
				1891
				1892	</FONT>
				1893	The shell sets
				1894	<FONT SIZE=-1><B>BASH_ARGV</B>
				1895
				1896	</FONT>
				1897	only when in extended debugging mode
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1898	(see the description of the
				1899	<B>extdebug</B>
				1900
				1901	option to the
				1902	<B>shopt</B>
				1903
				1904	builtin below)
				1905	<DT><B>BASH_CMDS</B>
				1906
				1907	<DD>
				1908	An associative array variable whose members correspond to the internal
				1909	hash table of commands as maintained by the <B>hash</B> builtin.
				1910	Elements added to this array appear in the hash table; unsetting array
				1911	elements cause commands to be removed from the hash table.
				1912	<DT><B>BASH_COMMAND</B>
				1913
				1914	<DD>
				1915	The command currently being executed or about to be executed, unless the
				1916	shell is executing a command as the result of a trap,
				1917	in which case it is the command executing at the time of the trap.
				1918	<DT><B>BASH_EXECUTION_STRING</B>
				1919
				1920	<DD>
				1921	The command argument to the <B>-c</B> invocation option.
				1922	<DT><B>BASH_LINENO</B>
				1923
				1924	<DD>
				1925	An array variable whose members are the line numbers in source files
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1926	where each corresponding member of
				1927	<FONT SIZE=-1><B>FUNCNAME</B>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1928
				1929	</FONT>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1930	was invoked.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1931	<B>${BASH_LINENO[</B><I>$i</I><B>]}</B> is the line number in the source
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1932	file (<B>${BASH_SOURCE[</B><I>$i+1</I><B>]}</B>) where
				1933	<B>${FUNCNAME[</B><I>$i</I><B>]}</B> was called
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1934	(or <B>${BASH_LINENO[</B><I>$i-1</I><B>]}</B> if referenced within another
				1935	shell function).
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1936	Use
				1937	<FONT SIZE=-1><B>LINENO</B>
				1938
				1939	</FONT>
				1940	to obtain the current line number.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1941	<DT><B>BASH_REMATCH</B>
				1942
				1943	<DD>
				1944	An array variable whose members are assigned by the <B>=~</B> binary
				1945	operator to the <B>[[</B> conditional command.
				1946	The element with index 0 is the portion of the string
				1947	matching the entire regular expression.
				1948	The element with index <I>n</I> is the portion of the
				1949	string matching the <I>n</I>th parenthesized subexpression.
				1950	This variable is read-only.
				1951	<DT><B>BASH_SOURCE</B>
				1952
				1953	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1954	An array variable whose members are the source filenames
				1955	where the corresponding shell function names in the
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	1956	<FONT SIZE=-1><B>FUNCNAME</B>
				1957
				1958	</FONT>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	1959	array variable are defined.
				1960	The shell function
				1961	<B>${FUNCNAME[</B><I>$i</I><B>]}</B> is defined in the file
				1962	<B>${BASH_SOURCE[</B><I>$i</I><B>]}</B> and called from
				1963	<B>${BASH_SOURCE[</B><I>$i+1</I><B>]}</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1964	<DT><B>BASH_SUBSHELL</B>
				1965
				1966	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	1967	Incremented by one within each subshell or subshell environment when
				1968	the shell begins executing in that environment.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1969	The initial value is 0.
				1970	<DT><B>BASH_VERSINFO</B>
				1971
				1972	<DD>
				1973	A readonly array variable whose members hold version information for
				1974	this instance of
				1975	<B>bash</B>.
				1976
				1977	The values assigned to the array members are as follows:
				1978	<P>
				1979	<DL COMPACT><DT><DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	1980	<DL COMPACT>
				1981	<DT><B>BASH_VERSINFO[</B>0]
				1982
				1983	<DD>
				1984	The major version number (the <I>release</I>).
				1985	<DT><B>BASH_VERSINFO[</B>1]
				1986
				1987	<DD>
				1988	The minor version number (the <I>version</I>).
				1989	<DT><B>BASH_VERSINFO[</B>2]
				1990
				1991	<DD>
				1992	The patch level.
				1993	<DT><B>BASH_VERSINFO[</B>3]
				1994
				1995	<DD>
				1996	The build version.
				1997	<DT><B>BASH_VERSINFO[</B>4]
				1998
				1999	<DD>
				2000	The release status (e.g., <I>beta1</I>).
				2001	<DT><B>BASH_VERSINFO[</B>5]
				2002
				2003	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2004	The value of
				2005	<FONT SIZE=-1><B>MACHTYPE</B>.
				2006
				2007	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2008	</DL></DL>
				2009
				2010	<DT><B>BASH_VERSION</B>
				2011
				2012	<DD>
				2013	Expands to a string describing the version of this instance of
				2014	<B>bash</B>.
				2015
				2016	<DT><B>COMP_CWORD</B>
				2017
				2018	<DD>
				2019	An index into <B>${COMP_WORDS}</B> of the word containing the current
				2020	cursor position.
				2021	This variable is available only in shell functions invoked by the
				2022	programmable completion facilities (see <B>Programmable Completion</B>
				2023	below).
				2024	<DT><B>COMP_KEY</B>
				2025
				2026	<DD>
				2027	The key (or final key of a key sequence) used to invoke the current
				2028	completion function.
				2029	<DT><B>COMP_LINE</B>
				2030
				2031	<DD>
				2032	The current command line.
				2033	This variable is available only in shell functions and external
				2034	commands invoked by the
				2035	programmable completion facilities (see <B>Programmable Completion</B>
				2036	below).
				2037	<DT><B>COMP_POINT</B>
				2038
				2039	<DD>
				2040	The index of the current cursor position relative to the beginning of
				2041	the current command.
				2042	If the current cursor position is at the end of the current command,
				2043	the value of this variable is equal to <B>${#COMP_LINE}</B>.
				2044	This variable is available only in shell functions and external
				2045	commands invoked by the
				2046	programmable completion facilities (see <B>Programmable Completion</B>
				2047	below).
				2048	<DT><B>COMP_TYPE</B>
				2049
				2050	<DD>
				2051	Set to an integer value corresponding to the type of completion attempted
				2052	that caused a completion function to be called:
				2053	<I>TAB</I>, for normal completion,
				2054	<I>?</I>, for listing completions after successive tabs,
				2055	<I>!</I>, for listing alternatives on partial word completion,
				2056	<I>@</I>, to list completions if the word is not unmodified,
				2057	or
				2058	<I>%</I>, for menu completion.
				2059	This variable is available only in shell functions and external
				2060	commands invoked by the
				2061	programmable completion facilities (see <B>Programmable Completion</B>
				2062	below).
				2063	<DT><B>COMP_WORDBREAKS</B>
				2064
				2065	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2066	The set of characters that the <B>readline</B> library treats as word
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2067	separators when performing word completion.
				2068	If
				2069	<FONT SIZE=-1><B>COMP_WORDBREAKS</B>
				2070
				2071	</FONT>
				2072	is unset, it loses its special properties, even if it is
				2073	subsequently reset.
				2074	<DT><B>COMP_WORDS</B>
				2075
				2076	<DD>
				2077	An array variable (see <B>Arrays</B> below) consisting of the individual
				2078	words in the current command line.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2079	The line is split into words as <B>readline</B> would split it, using
				2080	<FONT SIZE=-1><B>COMP_WORDBREAKS</B>
				2081
				2082	</FONT>
				2083	as described above.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2084	This variable is available only in shell functions invoked by the
				2085	programmable completion facilities (see <B>Programmable Completion</B>
				2086	below).
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2087	<DT><B>COPROC</B>
				2088
				2089	<DD>
				2090	An array variable (see <B>Arrays</B> below) created to hold the file descriptors
				2091	for output from and input to an unnamed coprocess (see <B>Coprocesses</B>
				2092	above).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2093	<DT><B>DIRSTACK</B>
				2094
				2095	<DD>
				2096	An array variable (see
				2097	<B>Arrays</B>
				2098
				2099	below) containing the current contents of the directory stack.
				2100	Directories appear in the stack in the order they are displayed by the
				2101	<B>dirs</B>
				2102
				2103	builtin.
				2104	Assigning to members of this array variable may be used to modify
				2105	directories already in the stack, but the
				2106	<B>pushd</B>
				2107
				2108	and
				2109	<B>popd</B>
				2110
				2111	builtins must be used to add and remove directories.
				2112	Assignment to this variable will not change the current directory.
				2113	If
				2114	<FONT SIZE=-1><B>DIRSTACK</B>
				2115
				2116	</FONT>
				2117	is unset, it loses its special properties, even if it is
				2118	subsequently reset.
				2119	<DT><B>EUID</B>
				2120
				2121	<DD>
				2122	Expands to the effective user ID of the current user, initialized at
				2123	shell startup. This variable is readonly.
				2124	<DT><B>FUNCNAME</B>
				2125
				2126	<DD>
				2127	An array variable containing the names of all shell functions
				2128	currently in the execution call stack.
				2129	The element with index 0 is the name of any currently-executing
				2130	shell function.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2131	The bottom-most element (the one with the highest index) is
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2132	<TT>"main"</TT>.
				2133
				2134	This variable exists only when a shell function is executing.
				2135	Assignments to
				2136	<FONT SIZE=-1><B>FUNCNAME</B>
				2137
				2138	</FONT>
				2139	have no effect and return an error status.
				2140	If
				2141	<FONT SIZE=-1><B>FUNCNAME</B>
				2142
				2143	</FONT>
				2144	is unset, it loses its special properties, even if it is
				2145	subsequently reset.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2146	<P>
				2147
				2148
				2149	This variable can be used with <B>BASH_LINENO</B> and <B>BASH_SOURCE</B>.
				2150	Each element of <B>FUNCNAME</B> has corresponding elements in
				2151	<B>BASH_LINENO</B> and <B>BASH_SOURCE</B> to describe the call stack.
				2152	For instance, <B>${FUNCNAME[</B><I>$i</I><B>]}</B> was called from the file
				2153	<B>${BASH_SOURCE[</B><I>$i+1</I><B>]}</B> at line number
				2154	<B>${BASH_LINENO[</B><I>$i</I><B>]}</B>.
				2155	The <B>caller</B> builtin displays the current call stack using this
				2156	information.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2157	<DT><B>GROUPS</B>
				2158
				2159	<DD>
				2160	An array variable containing the list of groups of which the current
				2161	user is a member.
				2162	Assignments to
				2163	<FONT SIZE=-1><B>GROUPS</B>
				2164
				2165	</FONT>
				2166	have no effect and return an error status.
				2167	If
				2168	<FONT SIZE=-1><B>GROUPS</B>
				2169
				2170	</FONT>
				2171	is unset, it loses its special properties, even if it is
				2172	subsequently reset.
				2173	<DT><B>HISTCMD</B>
				2174
				2175	<DD>
				2176	The history number, or index in the history list, of the current
				2177	command.
				2178	If
				2179	<FONT SIZE=-1><B>HISTCMD</B>
				2180
				2181	</FONT>
				2182	is unset, it loses its special properties, even if it is
				2183	subsequently reset.
				2184	<DT><B>HOSTNAME</B>
				2185
				2186	<DD>
				2187	Automatically set to the name of the current host.
				2188	<DT><B>HOSTTYPE</B>
				2189
				2190	<DD>
				2191	Automatically set to a string that uniquely
				2192	describes the type of machine on which
				2193	<B>bash</B>
				2194
				2195	is executing.
				2196	The default is system-dependent.
				2197	<DT><B>LINENO</B>
				2198
				2199	<DD>
				2200	Each time this parameter is referenced, the shell substitutes
				2201	a decimal number representing the current sequential line number
				2202	(starting with 1) within a script or function. When not in a
				2203	script or function, the value substituted is not guaranteed to
				2204	be meaningful.
				2205	If
				2206	<FONT SIZE=-1><B>LINENO</B>
				2207
				2208	</FONT>
				2209	is unset, it loses its special properties, even if it is
				2210	subsequently reset.
				2211	<DT><B>MACHTYPE</B>
				2212
				2213	<DD>
				2214	Automatically set to a string that fully describes the system
				2215	type on which
				2216	<B>bash</B>
				2217
				2218	is executing, in the standard GNU <I>cpu-company-system</I> format.
				2219	The default is system-dependent.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2220	<DT><B>MAPFILE</B>
				2221
				2222	<DD>
				2223	An array variable (see <B>Arrays</B> below) created to hold the text
				2224	read by the <B>mapfile</B> builtin when no variable name is supplied.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2225	<DT><B>OLDPWD</B>
				2226
				2227	<DD>
				2228	The previous working directory as set by the
				2229	<B>cd</B>
				2230
				2231	command.
				2232	<DT><B>OPTARG</B>
				2233
				2234	<DD>
				2235	The value of the last option argument processed by the
				2236	<B>getopts</B>
				2237
				2238	builtin command (see
				2239	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				2240
				2241	</FONT>
				2242	below).
				2243	<DT><B>OPTIND</B>
				2244
				2245	<DD>
				2246	The index of the next argument to be processed by the
				2247	<B>getopts</B>
				2248
				2249	builtin command (see
				2250	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				2251
				2252	</FONT>
				2253	below).
				2254	<DT><B>OSTYPE</B>
				2255
				2256	<DD>
				2257	Automatically set to a string that
				2258	describes the operating system on which
				2259	<B>bash</B>
				2260
				2261	is executing.
				2262	The default is system-dependent.
				2263	<DT><B>PIPESTATUS</B>
				2264
				2265	<DD>
				2266	An array variable (see
				2267	<B>Arrays</B>
				2268
				2269	below) containing a list of exit status values from the processes
				2270	in the most-recently-executed foreground pipeline (which may
				2271	contain only a single command).
				2272	<DT><B>PPID</B>
				2273
				2274	<DD>
				2275	The process ID of the shell's parent. This variable is readonly.
				2276	<DT><B>PWD</B>
				2277
				2278	<DD>
				2279	The current working directory as set by the
				2280	<B>cd</B>
				2281
				2282	command.
				2283	<DT><B>RANDOM</B>
				2284
				2285	<DD>
				2286	Each time this parameter is referenced, a random integer between
				2287	0 and 32767 is
				2288	generated. The sequence of random numbers may be initialized by assigning
				2289	a value to
				2290	<FONT SIZE=-1><B>RANDOM</B>.
				2291
				2292	</FONT>
				2293	If
				2294	<FONT SIZE=-1><B>RANDOM</B>
				2295
				2296	</FONT>
				2297	is unset, it loses its special properties, even if it is
				2298	subsequently reset.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2299	<DT><B>READLINE_LINE</B>
				2300
				2301	<DD>
				2302	The contents of the
				2303	<B>readline</B>
				2304
				2305	line buffer, for use with
				2306	<TT>bind -x</TT>
				2307
				2308	(see
				2309	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				2310
				2311	</FONT>
				2312	below).
				2313	<DT><B>READLINE_POINT</B>
				2314
				2315	<DD>
				2316	The position of the insertion point in the
				2317	<B>readline</B>
				2318
				2319	line buffer, for use with
				2320	<TT>bind -x</TT>
				2321
				2322	(see
				2323	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				2324
				2325	</FONT>
				2326	below).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2327	<DT><B>REPLY</B>
				2328
				2329	<DD>
				2330	Set to the line of input read by the
				2331	<B>read</B>
				2332
				2333	builtin command when no arguments are supplied.
				2334	<DT><B>SECONDS</B>
				2335
				2336	<DD>
				2337	Each time this parameter is
				2338	referenced, the number of seconds since shell invocation is returned. If a
				2339	value is assigned to
				2340	<FONT SIZE=-1><B>SECONDS</B>,
				2341
				2342	</FONT>
				2343	the value returned upon subsequent
				2344	references is
				2345	the number of seconds since the assignment plus the value assigned.
				2346	If
				2347	<FONT SIZE=-1><B>SECONDS</B>
				2348
				2349	</FONT>
				2350	is unset, it loses its special properties, even if it is
				2351	subsequently reset.
				2352	<DT><B>SHELLOPTS</B>
				2353
				2354	<DD>
				2355	A colon-separated list of enabled shell options. Each word in
				2356	the list is a valid argument for the
				2357	<B>-o</B>
				2358
				2359	option to the
				2360	<B>set</B>
				2361
				2362	builtin command (see
				2363	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				2364
				2365	</FONT>
				2366	below). The options appearing in
				2367	<FONT SIZE=-1><B>SHELLOPTS</B>
				2368
				2369	</FONT>
				2370	are those reported as
				2371	<I>on</I>
				2372
				2373	by <B>set -o</B>.
				2374	If this variable is in the environment when
				2375	<B>bash</B>
				2376
				2377	starts up, each shell option in the list will be enabled before
				2378	reading any startup files.
				2379	This variable is read-only.
				2380	<DT><B>SHLVL</B>
				2381
				2382	<DD>
				2383	Incremented by one each time an instance of
				2384	<B>bash</B>
				2385
				2386	is started.
				2387	<DT><B>UID</B>
				2388
				2389	<DD>
				2390	Expands to the user ID of the current user, initialized at shell startup.
				2391	This variable is readonly.
				2392
				2393	</DL>
				2394	<P>
				2395
				2396	The following variables are used by the shell. In some cases,
				2397	<B>bash</B>
				2398
				2399	assigns a default value to a variable; these cases are noted
				2400	below.
				2401	<P>
				2402
				2403
				2404	<DL COMPACT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2405	<DT><B>BASH_COMPAT</B>
				2406
				2407	<DD>
				2408	The value is used to set the shell's compatibility level.
				2409	See the description of the <B>shopt</B> builtin below under
				2410	<B>SHELL BUILTIN COMMANDS</B>
				2411	for a description of the various compatibility
				2412	levels and their effects.
				2413	The value may be a decimal number (e.g., 4.2) or an integer (e.g., 42)
				2414	corresponding to the desired compatibility level.
				2415	If <B>BASH_COMPAT</B> is unset or set to the empty string, the compatibility
				2416	level is set to the default for the current version.
				2417	If <B>BASH_COMPAT</B> is set to a value that is not one of the valid
				2418	compatibility levels, the shell prints an error message and sets the
				2419	compatibility level to the default for the current version.
				2420	The valid compatibility levels correspond to the compatibility options
				2421	accepted by the <B>shopt</B> builtin described below (for example,
				2422	<B>compat42</B> means that 4.2 and 42 are valid values).
				2423	The current version is also a valid value.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2424	<DT><B>BASH_ENV</B>
				2425
				2426	<DD>
				2427	If this parameter is set when <B>bash</B> is executing a shell script,
				2428	its value is interpreted as a filename containing commands to
				2429	initialize the shell, as in
				2430	<A HREF="file:~/.bashrc"><I>~/.bashrc</I></A>.
				2431
				2432	The value of
				2433	<FONT SIZE=-1><B>BASH_ENV</B>
				2434
				2435	</FONT>
				2436	is subjected to parameter expansion, command substitution, and arithmetic
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2437	expansion before being interpreted as a filename.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2438	<FONT SIZE=-1><B>PATH</B>
				2439
				2440	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2441	is not used to search for the resultant filename.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2442	<DT><B>BASH_XTRACEFD</B>
				2443
				2444	<DD>
				2445	If set to an integer corresponding to a valid file descriptor, <B>bash</B>
				2446	will write the trace output generated when
				2447	<TT>set -x</TT>
				2448
				2449	is enabled to that file descriptor.
				2450	The file descriptor is closed when
				2451	<FONT SIZE=-1><B>BASH_XTRACEFD</B>
				2452
				2453	</FONT>
				2454	is unset or assigned a new value.
				2455	Unsetting
				2456	<FONT SIZE=-1><B>BASH_XTRACEFD</B>
				2457
				2458	</FONT>
				2459	or assigning it the empty string causes the
				2460	trace output to be sent to the standard error.
				2461	Note that setting
				2462	<FONT SIZE=-1><B>BASH_XTRACEFD</B>
				2463
				2464	</FONT>
				2465	to 2 (the standard error file
				2466	descriptor) and then unsetting it will result in the standard error
				2467	being closed.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2468	<DT><B>CDPATH</B>
				2469
				2470	<DD>
				2471	The search path for the
				2472	<B>cd</B>
				2473
				2474	command.
				2475	This is a colon-separated list of directories in which the shell looks
				2476	for destination directories specified by the
				2477	<B>cd</B>
				2478
				2479	command.
				2480	A sample value is
				2481	<TT>".:~:/usr"</TT>.
				2482
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2483	<DT><B>CHILD_MAX</B>
				2484
				2485	<DD>
				2486	Set the number of exited child status values for the shell to remember.
				2487	Bash will not allow this value to be decreased below a POSIX-mandated
				2488	minimum, and there is a maximum value (currently 8192) that this may
				2489	not exceed.
				2490	The minimum value is system-dependent.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2491	<DT><B>COLUMNS</B>
				2492
				2493	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2494	Used by the <B>select</B> compound command to determine the terminal width
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2495	when printing selection lists.
				2496	Automatically set if the
				2497	<B>checkwinsize</B>
				2498
				2499	option is enabled or in an interactive shell upon receipt of a
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2500	<FONT SIZE=-1><B>SIGWINCH</B>.
				2501
				2502	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2503	<DT><B>COMPREPLY</B>
				2504
				2505	<DD>
				2506	An array variable from which <B>bash</B> reads the possible completions
				2507	generated by a shell function invoked by the programmable completion
				2508	facility (see <B>Programmable Completion</B> below).
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2509	Each array element contains one possible completion.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2510	<DT><B>EMACS</B>
				2511
				2512	<DD>
				2513	If <B>bash</B> finds this variable in the environment when the shell starts
				2514	with value
				2515	<TT>t</TT>,
				2516
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2517	it assumes that the shell is running in an Emacs shell buffer and disables
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2518	line editing.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2519	<DT><B>ENV</B>
				2520
				2521	<DD>
				2522	Similar to
				2523	<FONT SIZE=-1><B>BASH_ENV</B>;
				2524
				2525	</FONT>
				2526	used when the shell is invoked in POSIX mode.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2527	<DT><B>FCEDIT</B>
				2528
				2529	<DD>
				2530	The default editor for the
				2531	<B>fc</B>
				2532
				2533	builtin command.
				2534	<DT><B>FIGNORE</B>
				2535
				2536	<DD>
				2537	A colon-separated list of suffixes to ignore when performing
				2538	filename completion (see
				2539	<FONT SIZE=-1><B>READLINE</B>
				2540
				2541	</FONT>
				2542	below).
				2543	A filename whose suffix matches one of the entries in
				2544	<FONT SIZE=-1><B>FIGNORE</B>
				2545
				2546	</FONT>
				2547	is excluded from the list of matched filenames.
				2548	A sample value is
				2549	<TT>".o:~"</TT>.
				2550
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2551	<DT><B>FUNCNEST</B>
				2552
				2553	<DD>
				2554	If set to a numeric value greater than 0, defines a maximum function
				2555	nesting level. Function invocations that exceed this nesting level
				2556	will cause the current command to abort.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2557	<DT><B>GLOBIGNORE</B>
				2558
				2559	<DD>
				2560	A colon-separated list of patterns defining the set of filenames to
				2561	be ignored by pathname expansion.
				2562	If a filename matched by a pathname expansion pattern also matches one
				2563	of the patterns in
				2564	<FONT SIZE=-1><B>GLOBIGNORE</B>,
				2565
				2566	</FONT>
				2567	it is removed from the list of matches.
				2568	<DT><B>HISTCONTROL</B>
				2569
				2570	<DD>
				2571	A colon-separated list of values controlling how commands are saved on
				2572	the history list.
				2573	If the list of values includes
				2574	<I>ignorespace</I>,
				2575
				2576	lines which begin with a
				2577	<B>space</B>
				2578
				2579	character are not saved in the history list.
				2580	A value of
				2581	<I>ignoredups</I>
				2582
				2583	causes lines matching the previous history entry to not be saved.
				2584	A value of
				2585	<I>ignoreboth</I>
				2586
				2587	is shorthand for <I>ignorespace</I> and <I>ignoredups</I>.
				2588	A value of
				2589	<I>erasedups</I>
				2590
				2591	causes all previous lines matching the current line to be removed from
				2592	the history list before that line is saved.
				2593	Any value not in the above list is ignored.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2594	If
				2595	<FONT SIZE=-1><B>HISTCONTROL</B>
				2596
				2597	</FONT>
				2598	is unset, or does not include a valid value,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2599	all lines read by the shell parser are saved on the history list,
				2600	subject to the value of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2601	<FONT SIZE=-1><B>HISTIGNORE</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2602
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2603	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2604	The second and subsequent lines of a multi-line compound command are
				2605	not tested, and are added to the history regardless of the value of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2606	<FONT SIZE=-1><B>HISTCONTROL</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2607
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2608	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2609	<DT><B>HISTFILE</B>
				2610
				2611	<DD>
				2612	The name of the file in which command history is saved (see
				2613	<FONT SIZE=-1><B>HISTORY</B>
				2614
				2615	</FONT>
				2616	below). The default value is <A HREF="file:~/.bash_history"><I>~/.bash_history</I></A>. If unset, the
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2617	command history is not saved when a shell exits.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2618	<DT><B>HISTFILESIZE</B>
				2619
				2620	<DD>
				2621	The maximum number of lines contained in the history file. When this
				2622	variable is assigned a value, the history file is truncated, if
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2623	necessary,
				2624	to contain no more than that number of lines by removing the oldest entries.
				2625	The history file is also truncated to this size after
				2626	writing it when a shell exits.
				2627	If the value is 0, the history file is truncated to zero size.
				2628	Non-numeric values and numeric values less than zero inhibit truncation.
				2629	The shell sets the default value to the value of <B>HISTSIZE</B>
				2630	after reading any startup files.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2631	<DT><B>HISTIGNORE</B>
				2632
				2633	<DD>
				2634	A colon-separated list of patterns used to decide which command lines
				2635	should be saved on the history list. Each pattern is anchored at the
				2636	beginning of the line and must match the complete line (no implicit
				2637	`<B>*</B>' is appended). Each pattern is tested against the line
				2638	after the checks specified by
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2639	<FONT SIZE=-1><B>HISTCONTROL</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2640
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2641	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2642	are applied.
				2643	In addition to the normal shell pattern matching characters, `<B>&</B>'
				2644	matches the previous history line. `<B>&</B>' may be escaped using a
				2645	backslash; the backslash is removed before attempting a match.
				2646	The second and subsequent lines of a multi-line compound command are
				2647	not tested, and are added to the history regardless of the value of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2648	<FONT SIZE=-1><B>HISTIGNORE</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2649
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2650	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2651	<DT><B>HISTSIZE</B>
				2652
				2653	<DD>
				2654	The number of commands to remember in the command history (see
				2655	<FONT SIZE=-1><B>HISTORY</B>
				2656
				2657	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2658	below).
				2659	If the value is 0, commands are not saved in the history list.
				2660	Numeric values less than zero result in every command being saved
				2661	on the history list (there is no limit).
				2662	The shell sets the default value to 500 after reading any startup files.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2663	<DT><B>HISTTIMEFORMAT</B>
				2664
				2665	<DD>
				2666	If this variable is set and not null, its value is used as a format string
				2667	for <I>strftime</I>(3) to print the time stamp associated with each history
				2668	entry displayed by the <B>history</B> builtin.
				2669	If this variable is set, time stamps are written to the history file so
				2670	they may be preserved across shell sessions.
				2671	This uses the history comment character to distinguish timestamps from
				2672	other history lines.
				2673	<DT><B>HOME</B>
				2674
				2675	<DD>
				2676	The home directory of the current user; the default argument for the
				2677	<B>cd</B> builtin command.
				2678	The value of this variable is also used when performing tilde expansion.
				2679	<DT><B>HOSTFILE</B>
				2680
				2681	<DD>
				2682	Contains the name of a file in the same format as
				2683
				2684	<I>/etc/hosts</I>
				2685
				2686	that should be read when the shell needs to complete a
				2687	hostname.
				2688	The list of possible hostname completions may be changed while the
				2689	shell is running;
				2690	the next time hostname completion is attempted after the
				2691	value is changed,
				2692	<B>bash</B>
				2693
				2694	adds the contents of the new file to the existing list.
				2695	If
				2696	<FONT SIZE=-1><B>HOSTFILE</B>
				2697
				2698	</FONT>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2699	is set, but has no value, or does not name a readable file,
				2700	<B>bash</B> attempts to read
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2701
				2702	<I>/etc/hosts</I>
				2703
				2704	to obtain the list of possible hostname completions.
				2705	When
				2706	<FONT SIZE=-1><B>HOSTFILE</B>
				2707
				2708	</FONT>
				2709	is unset, the hostname list is cleared.
				2710	<DT><B>IFS</B>
				2711
				2712	<DD>
				2713	The
				2714	<I>Internal Field Separator</I>
				2715
				2716	that is used
				2717	for word splitting after expansion and to
				2718	split lines into words with the
				2719	<B>read</B>
				2720
				2721	builtin command. The default value is
				2722	``<space><tab><newline>''.
				2723	<DT><B>IGNOREEOF</B>
				2724
				2725	<DD>
				2726	Controls the
				2727	action of an interactive shell on receipt of an
				2728	<FONT SIZE=-1><B>EOF</B>
				2729
				2730	</FONT>
				2731	character as the sole input. If set, the value is the number of
				2732	consecutive
				2733	<FONT SIZE=-1><B>EOF</B>
				2734
				2735	</FONT>
				2736	characters which must be
				2737	typed as the first characters on an input line before
				2738	<B>bash</B>
				2739
				2740	exits. If the variable exists but does not have a numeric value, or
				2741	has no value, the default value is 10. If it does not exist,
				2742	<FONT SIZE=-1><B>EOF</B>
				2743
				2744	</FONT>
				2745	signifies the end of input to the shell.
				2746	<DT><B>INPUTRC</B>
				2747
				2748	<DD>
				2749	The filename for the
				2750	<B>readline</B>
				2751
				2752	startup file, overriding the default of
				2753
				2754	<A HREF="file:~/.inputrc"><I>~/.inputrc</I></A>
				2755
				2756	(see
				2757	<FONT SIZE=-1><B>READLINE</B>
				2758
				2759	</FONT>
				2760	below).
				2761	<DT><B>LANG</B>
				2762
				2763	<DD>
				2764	Used to determine the locale category for any category not specifically
				2765	selected with a variable starting with <B>LC_</B>.
				2766	<DT><B>LC_ALL</B>
				2767
				2768	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2769	This variable overrides the value of
				2770	<FONT SIZE=-1><B>LANG</B>
				2771
				2772	</FONT>
				2773	and any other
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2774	<B>LC_</B> variable specifying a locale category.
				2775	<DT><B>LC_COLLATE</B>
				2776
				2777	<DD>
				2778	This variable determines the collation order used when sorting the
				2779	results of pathname expansion, and determines the behavior of range
				2780	expressions, equivalence classes, and collating sequences within
				2781	pathname expansion and pattern matching.
				2782	<DT><B>LC_CTYPE</B>
				2783
				2784	<DD>
				2785	This variable determines the interpretation of characters and the
				2786	behavior of character classes within pathname expansion and pattern
				2787	matching.
				2788	<DT><B>LC_MESSAGES</B>
				2789
				2790	<DD>
				2791	This variable determines the locale used to translate double-quoted
				2792	strings preceded by a <B>$</B>.
				2793	<DT><B>LC_NUMERIC</B>
				2794
				2795	<DD>
				2796	This variable determines the locale category used for number formatting.
				2797	<DT><B>LINES</B>
				2798
				2799	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2800	Used by the <B>select</B> compound command to determine the column length
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2801	for printing selection lists.
				2802	Automatically set if the
				2803	<B>checkwinsize</B>
				2804
				2805	option is enabled or in an interactive shell upon receipt of a
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2806	<FONT SIZE=-1><B>SIGWINCH</B>.
				2807
				2808	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2809	<DT><B>MAIL</B>
				2810
				2811	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2812	If this parameter is set to a file or directory name and the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2813	<FONT SIZE=-1><B>MAILPATH</B>
				2814
				2815	</FONT>
				2816	variable is not set,
				2817	<B>bash</B>
				2818
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	2819	informs the user of the arrival of mail in the specified file or
				2820	Maildir-format directory.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2821	<DT><B>MAILCHECK</B>
				2822
				2823	<DD>
				2824	Specifies how
				2825	often (in seconds)
				2826	<B>bash</B>
				2827
				2828	checks for mail. The default is 60 seconds. When it is time to check
				2829	for mail, the shell does so before displaying the primary prompt.
				2830	If this variable is unset, or set to a value that is not a number
				2831	greater than or equal to zero, the shell disables mail checking.
				2832	<DT><B>MAILPATH</B>
				2833
				2834	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2835	A colon-separated list of filenames to be checked for mail.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2836	The message to be printed when mail arrives in a particular file
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2837	may be specified by separating the filename from the message with a `?'.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2838	When used in the text of the message, <B>$_</B> expands to the name of
				2839	the current mailfile.
				2840	Example:
				2841	<DL COMPACT><DT><DD>
				2842	<P>
				2843
				2844	<B>MAILPATH</B>=aq/var/mail/bfox?"You have mail":~/shell-mail?"$_ has mail!"aq
				2845	<P>
				2846
				2847	<B>Bash</B>
				2848
				2849	supplies a default value for this variable, but the location of the user
				2850	mail files that it uses is system dependent (e.g., /var/mail/<B>$USER</B>).
				2851	</DL>
				2852
				2853	<DT><B>OPTERR</B>
				2854
				2855	<DD>
				2856	If set to the value 1,
				2857	<B>bash</B>
				2858
				2859	displays error messages generated by the
				2860	<B>getopts</B>
				2861
				2862	builtin command (see
				2863	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				2864
				2865	</FONT>
				2866	below).
				2867	<FONT SIZE=-1><B>OPTERR</B>
				2868
				2869	</FONT>
				2870	is initialized to 1 each time the shell is invoked or a shell
				2871	script is executed.
				2872	<DT><B>PATH</B>
				2873
				2874	<DD>
				2875	The search path for commands. It
				2876	is a colon-separated list of directories in which
				2877	the shell looks for commands (see
				2878	<FONT SIZE=-1><B>COMMAND EXECUTION</B>
				2879
				2880	</FONT>
				2881	below).
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2882	A zero-length (null) directory name in the value of
				2883	<FONT SIZE=-1><B>PATH</B>
				2884
				2885	</FONT>
				2886	indicates the current directory.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2887	A null directory name may appear as two adjacent colons, or as an initial
				2888	or trailing colon.
				2889	The default path is system-dependent,
				2890	and is set by the administrator who installs
				2891	<B>bash</B>.
				2892
				2893	A common value is
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	2894	<TT>/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin</TT>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2895
				2896	<DT><B>POSIXLY_CORRECT</B>
				2897
				2898	<DD>
				2899	If this variable is in the environment when <B>bash</B> starts, the shell
				2900	enters <I>posix mode</I> before reading the startup files, as if the
				2901	<B>--posix</B>
				2902
				2903	invocation option had been supplied. If it is set while the shell is
				2904	running, <B>bash</B> enables <I>posix mode</I>, as if the command
				2905	<TT>set -o posix</TT>
				2906
				2907	had been executed.
				2908	<DT><B>PROMPT_COMMAND</B>
				2909
				2910	<DD>
				2911	If set, the value is executed as a command prior to issuing each primary
				2912	prompt.
				2913	<DT><B>PROMPT_DIRTRIM</B>
				2914
				2915	<DD>
				2916	If set to a number greater than zero, the value is used as the number of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2917	trailing directory components to retain when expanding the <B>\w</B> and
				2918	<B>\W</B> prompt string escapes (see
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2919	<FONT SIZE=-1><B>PROMPTING</B>
				2920
				2921	</FONT>
				2922	below). Characters removed are replaced with an ellipsis.
				2923	<DT><B>PS1</B>
				2924
				2925	<DD>
				2926	The value of this parameter is expanded (see
				2927	<FONT SIZE=-1><B>PROMPTING</B>
				2928
				2929	</FONT>
				2930	below) and used as the primary prompt string. The default value is
				2931	``<B>\s-\v\$ </B>''.
				2932	<DT><B>PS2</B>
				2933
				2934	<DD>
				2935	The value of this parameter is expanded as with
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2936	<FONT SIZE=-1><B>PS1</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2937
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2938	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2939	and used as the secondary prompt string. The default is
				2940	``<B>> </B>''.
				2941	<DT><B>PS3</B>
				2942
				2943	<DD>
				2944	The value of this parameter is used as the prompt for the
				2945	<B>select</B>
				2946
				2947	command (see
				2948	<FONT SIZE=-1><B>SHELL GRAMMAR</B>
				2949
				2950	</FONT>
				2951	above).
				2952	<DT><B>PS4</B>
				2953
				2954	<DD>
				2955	The value of this parameter is expanded as with
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2956	<FONT SIZE=-1><B>PS1</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2957
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	2958	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	2959	and the value is printed before each command
				2960	<B>bash</B>
				2961
				2962	displays during an execution trace. The first character of
				2963	<FONT SIZE=-1><B>PS4</B>
				2964
				2965	</FONT>
				2966	is replicated multiple times, as necessary, to indicate multiple
				2967	levels of indirection. The default is ``<B>+ </B>''.
				2968	<DT><B>SHELL</B>
				2969
				2970	<DD>
				2971	The full pathname to the shell is kept in this environment variable.
				2972	If it is not set when the shell starts,
				2973	<B>bash</B>
				2974
				2975	assigns to it the full pathname of the current user's login shell.
				2976	<DT><B>TIMEFORMAT</B>
				2977
				2978	<DD>
				2979	The value of this parameter is used as a format string specifying
				2980	how the timing information for pipelines prefixed with the
				2981	<B>time</B>
				2982
				2983	reserved word should be displayed.
				2984	The <B>%</B> character introduces an escape sequence that is
				2985	expanded to a time value or other information.
				2986	The escape sequences and their meanings are as follows; the
				2987	braces denote optional portions.
				2988	<P>
				2989	<DL COMPACT><DT><DD>
				2990
				2991	<DL COMPACT>
				2992	<DT><B>%%</B>
				2993
				2994	<DD>
				2995	A literal <B>%</B>.
				2996	<DT><B>%[</B><I>p</I>][l]R
				2997
				2998	<DD>
				2999	The elapsed time in seconds.
				3000	<DT><B>%[</B><I>p</I>][l]U
				3001
				3002	<DD>
				3003	The number of CPU seconds spent in user mode.
				3004	<DT><B>%[</B><I>p</I>][l]S
				3005
				3006	<DD>
				3007	The number of CPU seconds spent in system mode.
				3008	<DT><B>%P</B>
				3009
				3010	<DD>
				3011	The CPU percentage, computed as (%U + %S) / %R.
				3012
				3013	</DL></DL>
				3014
				3015	<DT><DD>
				3016	The optional <I>p</I> is a digit specifying the <I>precision</I>,
				3017	the number of fractional digits after a decimal point.
				3018	A value of 0 causes no decimal point or fraction to be output.
				3019	At most three places after the decimal point may be specified;
				3020	values of <I>p</I> greater than 3 are changed to 3.
				3021	If <I>p</I> is not specified, the value 3 is used.
				3022	<DT><DD>
				3023	The optional <B>l</B> specifies a longer format, including
				3024	minutes, of the form <I>MM</I>m<I>SS</I>.<I>FF</I>s.
				3025	The value of <I>p</I> determines whether or not the fraction is
				3026	included.
				3027	<DT><DD>
				3028	If this variable is not set, <B>bash</B> acts as if it had the
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3029	value <B>$aq\nreal\t%3lR\nuser\t%3lU\nsys\t%3lSaq</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3030	If the value is null, no timing information is displayed.
				3031	A trailing newline is added when the format string is displayed.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3032
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3033	<DT><B>TMOUT</B>
				3034
				3035	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	3036	If set to a value greater than zero,
				3037	<FONT SIZE=-1><B>TMOUT</B>
				3038
				3039	</FONT>
				3040	is treated as the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3041	default timeout for the <B>read</B> builtin.
				3042	The <B>select</B> command terminates if input does not arrive
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	3043	after
				3044	<FONT SIZE=-1><B>TMOUT</B>
				3045
				3046	</FONT>
				3047	seconds when input is coming from a terminal.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3048	In an interactive shell, the value is interpreted as the
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3049	number of seconds to wait for a line of input after issuing the
				3050	primary prompt.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3051	<B>Bash</B>
				3052
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3053	terminates after waiting for that number of seconds if a complete
				3054	line of input does not arrive.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3055	<DT><B>TMPDIR</B>
				3056
				3057	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3058	If set, <B>bash</B> uses its value as the name of a directory in which
				3059	<B>bash</B> creates temporary files for the shell's use.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3060	<DT><B>auto_resume</B>
				3061
				3062	<DD>
				3063	This variable controls how the shell interacts with the user and
				3064	job control. If this variable is set, single word simple
				3065	commands without redirections are treated as candidates for resumption
				3066	of an existing stopped job. There is no ambiguity allowed; if there is
				3067	more than one job beginning with the string typed, the job most recently
				3068	accessed is selected. The
				3069	<I>name</I>
				3070
				3071	of a stopped job, in this context, is the command line used to
				3072	start it.
				3073	If set to the value
				3074	<I>exact</I>,
				3075
				3076	the string supplied must match the name of a stopped job exactly;
				3077	if set to
				3078	<I>substring</I>,
				3079
				3080	the string supplied needs to match a substring of the name of a
				3081	stopped job. The
				3082	<I>substring</I>
				3083
				3084	value provides functionality analogous to the
				3085	<B>%?</B>
				3086
				3087	job identifier (see
				3088	<FONT SIZE=-1><B>JOB CONTROL</B>
				3089
				3090	</FONT>
				3091	below). If set to any other value, the supplied string must
				3092	be a prefix of a stopped job's name; this provides functionality
				3093	analogous to the <B>%</B><I>string</I> job identifier.
				3094	<DT><B>histchars</B>
				3095
				3096	<DD>
				3097	The two or three characters which control history expansion
				3098	and tokenization (see
				3099	<FONT SIZE=-1><B>HISTORY EXPANSION</B>
				3100
				3101	</FONT>
				3102	below). The first character is the <I>history expansion</I> character,
				3103	the character which signals the start of a history
				3104	expansion, normally `<B>!</B>'.
				3105	The second character is the <I>quick substitution</I>
				3106	character, which is used as shorthand for re-running the previous
				3107	command entered, substituting one string for another in the command.
				3108	The default is `<B>^</B>'.
				3109	The optional third character is the character
				3110	which indicates that the remainder of the line is a comment when found
				3111	as the first character of a word, normally `<B>#</B>'. The history
				3112	comment character causes history substitution to be skipped for the
				3113	remaining words on the line. It does not necessarily cause the shell
				3114	parser to treat the rest of the line as a comment.
				3115
				3116	</DL>
				3117	<A NAME="lbAX"> </A>
				3118	<H4>Arrays</H4>
				3119
				3120	<B>Bash</B>
				3121
				3122	provides one-dimensional indexed and associative array variables.
				3123	Any variable may be used as an indexed array; the
				3124	<B>declare</B>
				3125
				3126	builtin will explicitly declare an array.
				3127	There is no maximum
				3128	limit on the size of an array, nor any requirement that members
				3129	be indexed or assigned contiguously.
				3130	Indexed arrays are referenced using integers (including arithmetic
				3131	expressions) and are zero-based; associative arrays are referenced
				3132	using arbitrary strings.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3133	Unless otherwise noted, indexed array indices must be non-negative integers.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3134	<P>
				3135
				3136	An indexed array is created automatically if any variable is assigned to
				3137	using the syntax <I>name</I>[<I>subscript</I>]=<I>value</I>. The
				3138	<I>subscript</I>
				3139
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3140	is treated as an arithmetic expression that must evaluate to a number.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3141	To explicitly declare an indexed array, use
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3142	<B>declare -a </B><I>name</I>
				3143
				3144	(see
				3145	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				3146
				3147	</FONT>
				3148	below).
				3149	<B>declare -a </B><I>name</I>[<I>subscript</I>]
				3150
				3151	is also accepted; the <I>subscript</I> is ignored.
				3152	<P>
				3153
				3154	Associative arrays are created using
				3155	<B>declare -A </B><I>name</I>.
				3156
				3157	<P>
				3158
				3159	Attributes may be
				3160	specified for an array variable using the
				3161	<B>declare</B>
				3162
				3163	and
				3164	<B>readonly</B>
				3165
				3166	builtins. Each attribute applies to all members of an array.
				3167	<P>
				3168
				3169	Arrays are assigned to using compound assignments of the form
				3170	<I>name</I>=<B>(</B>value<I>1</I> ... value<I>n</I><B>)</B>, where each
				3171	<I>value</I> is of the form [<I>subscript</I>]=<I>string</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3172	Indexed array assignments do not require anything but <I>string</I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3173	When assigning to indexed arrays, if the optional brackets and subscript
				3174	are supplied, that index is assigned to;
				3175	otherwise the index of the element assigned is the last index assigned
				3176	to by the statement plus one. Indexing starts at zero.
				3177	<P>
				3178
				3179	When assigning to an associative array, the subscript is required.
				3180	<P>
				3181
				3182	This syntax is also accepted by the
				3183	<B>declare</B>
				3184
				3185	builtin. Individual array elements may be assigned to using the
				3186	<I>name</I>[<I>subscript</I>]=<I>value</I> syntax introduced above.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3187	When assigning to an indexed array, if
				3188	<I>name</I>
				3189
				3190	is subscripted by a negative number, that number is
				3191	interpreted as relative to one greater than the maximum index of
				3192	<I>name</I>, so negative indices count back from the end of the
				3193	array, and an index of -1 references the last element.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3194	<P>
				3195
				3196	Any element of an array may be referenced using
				3197	${<I>name</I>[<I>subscript</I>]}. The braces are required to avoid
				3198	conflicts with pathname expansion. If
				3199	<I>subscript</I> is <B>@</B> or <B>*</B>, the word expands to
				3200	all members of <I>name</I>. These subscripts differ only when the
				3201	word appears within double quotes. If the word is double-quoted,
				3202	${<I>name</I>[*]} expands to a single
				3203	word with the value of each array member separated by the first
				3204	character of the
				3205	<FONT SIZE=-1><B>IFS</B>
				3206
				3207	</FONT>
				3208	special variable, and ${<I>name</I>[@]} expands each element of
				3209	<I>name</I> to a separate word. When there are no array members,
				3210	${<I>name</I>[@]} expands to nothing.
				3211	If the double-quoted expansion occurs within a word, the expansion of
				3212	the first parameter is joined with the beginning part of the original
				3213	word, and the expansion of the last parameter is joined with the last
				3214	part of the original word.
				3215	This is analogous to the expansion
				3216	of the special parameters <B>*</B> and <B>@</B> (see
				3217	<B>Special Parameters</B>
				3218
				3219	above). ${#<I>name</I>[<I>subscript</I>]} expands to the length of
				3220	${<I>name</I>[<I>subscript</I>]}. If <I>subscript</I> is <B>*</B> or
				3221	<B>@</B>, the expansion is the number of elements in the array.
				3222	Referencing an array variable without a subscript is equivalent to
				3223	referencing the array with a subscript of 0.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3224	If the
				3225	<I>subscript</I>
				3226
				3227	used to reference an element of an indexed array
				3228	evaluates to a number less than zero, it is
				3229	interpreted as relative to one greater than the maximum index of the array,
				3230	so negative indices count back from the end of the
				3231	array, and an index of -1 references the last element.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3232	<P>
				3233
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	3234	An array variable is considered set if a subscript has been assigned a
				3235	value. The null string is a valid value.
				3236	<P>
				3237
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3238	It is possible to obtain the keys (indices) of an array as well as the values.
				3239	${<B>!</B><I>name</I>[<I>@</I>]} and ${<B>!</B><I>name</I>[<I>*</I>]}
				3240	expand to the indices assigned in array variable <I>name</I>.
				3241	The treatment when in double quotes is similar to the expansion of the
				3242	special parameters <I>@</I> and <I>*</I> within double quotes.
				3243	<P>
				3244
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3245	The
				3246	<B>unset</B>
				3247
				3248	builtin is used to destroy arrays. <B>unset</B> <I>name</I>[<I>subscript</I>]
				3249	destroys the array element at index <I>subscript</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3250	Negative subscripts to indexed arrays are interpreted as described above.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	3251	Care must be taken to avoid unwanted side effects caused by pathname
				3252	expansion.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3253	<B>unset</B> <I>name</I>, where <I>name</I> is an array, or
				3254	<B>unset</B> <I>name</I>[<I>subscript</I>], where
				3255	<I>subscript</I> is <B>*</B> or <B>@</B>, removes the entire array.
				3256	<P>
				3257
				3258	The
				3259	<B>declare</B>,
				3260
				3261	<B>local</B>,
				3262
				3263	and
				3264	<B>readonly</B>
				3265
				3266	builtins each accept a
				3267	<B>-a</B>
				3268
				3269	option to specify an indexed array and a
				3270	<B>-A</B>
				3271
				3272	option to specify an associative array.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3273	If both options are supplied,
				3274	<B>-A</B>
				3275
				3276	takes precedence.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3277	The
				3278	<B>read</B>
				3279
				3280	builtin accepts a
				3281	<B>-a</B>
				3282
				3283	option to assign a list of words read from the standard input
				3284	to an array. The
				3285	<B>set</B>
				3286
				3287	and
				3288	<B>declare</B>
				3289
				3290	builtins display array values in a way that allows them to be
				3291	reused as assignments.
				3292	<A NAME="lbAY"> </A>
				3293	<H3>EXPANSION</H3>
				3294
				3295	Expansion is performed on the command line after it has been split into
				3296	words. There are seven kinds of expansion performed:
				3297	<I>brace expansion</I>,
				3298
				3299	<I>tilde expansion</I>,
				3300
				3301	<I>parameter and variable expansion</I>,
				3302
				3303	<I>command substitution</I>,
				3304
				3305	<I>arithmetic expansion</I>,
				3306
				3307	<I>word splitting</I>,
				3308
				3309	and
				3310	<I>pathname expansion</I>.
				3311
				3312	<P>
				3313
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3314	The order of expansions is:
				3315	brace expansion;
				3316	tilde expansion, parameter and variable expansion, arithmetic expansion,
				3317	and command substitution (done in a left-to-right fashion);
				3318	word splitting;
				3319	and pathname expansion.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3320	<P>
				3321
				3322	On systems that can support it, there is an additional expansion
				3323	available: <I>process substitution</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3324	This is performed at the
				3325	same time as tilde, parameter, variable, and arithmetic expansion and
				3326	command substitution.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3327	<P>
				3328
				3329	Only brace expansion, word splitting, and pathname expansion
				3330	can change the number of words of the expansion; other expansions
				3331	expand a single word to a single word.
				3332	The only exceptions to this are the expansions of
				3333	"<B>$@</B>" and "<B>${</B><I>name</I><B>[@]}</B>"
				3334	as explained above (see
				3335	<FONT SIZE=-1><B>PARAMETERS</B>).
				3336
				3337	</FONT>
				3338	<A NAME="lbAZ"> </A>
				3339	<H4>Brace Expansion</H4>
				3340
				3341	<P>
				3342
				3343	<I>Brace expansion</I>
				3344
				3345	is a mechanism by which arbitrary strings
				3346	may be generated. This mechanism is similar to
				3347	<I>pathname expansion</I>, but the filenames generated
				3348	need not exist. Patterns to be brace expanded take
				3349	the form of an optional
				3350	<I>preamble</I>,
				3351
				3352	followed by either a series of comma-separated strings or
				3353	a sequence expression between a pair of braces, followed by
				3354	an optional
				3355	<I>postscript</I>.
				3356
				3357	The preamble is prefixed to each string contained
				3358	within the braces, and the postscript is then appended
				3359	to each resulting string, expanding left to right.
				3360	<P>
				3361
				3362	Brace expansions may be nested. The results of each expanded
				3363	string are not sorted; left to right order is preserved.
				3364	For example, a<B>{</B>d,c,b<B>}</B>e expands into `ade ace abe'.
				3365	<P>
				3366
				3367	A sequence expression takes the form
				3368	<B>{</B><I>x</I><B>..</B><I>y</I><B>[..</B><I>incr</I><B>]}</B>,
				3369	where <I>x</I> and <I>y</I> are either integers or single characters,
				3370	and <I>incr</I>, an optional increment, is an integer.
				3371	When integers are supplied, the expression expands to each number between
				3372	<I>x</I> and <I>y</I>, inclusive.
				3373	Supplied integers may be prefixed with <I>0</I> to force each term to have the
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3374	same width.
				3375	When either <I>x</I> or y begins with a zero, the shell
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3376	attempts to force all generated terms to contain the same number of digits,
				3377	zero-padding where necessary.
				3378	When characters are supplied, the expression expands to each character
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3379	lexicographically between <I>x</I> and <I>y</I>, inclusive,
				3380	using the default C locale.
				3381	Note that both <I>x</I> and <I>y</I> must be of the same type.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3382	When the increment is supplied, it is used as the difference between
				3383	each term. The default increment is 1 or -1 as appropriate.
				3384	<P>
				3385
				3386	Brace expansion is performed before any other expansions,
				3387	and any characters special to other expansions are preserved
				3388	in the result. It is strictly textual.
				3389	<B>Bash</B>
				3390
				3391	does not apply any syntactic interpretation to the context of the
				3392	expansion or the text between the braces.
				3393	<P>
				3394
				3395	A correctly-formed brace expansion must contain unquoted opening
				3396	and closing braces, and at least one unquoted comma or a valid
				3397	sequence expression.
				3398	Any incorrectly formed brace expansion is left unchanged.
				3399	A <B>{</B> or <B>,</B> may be quoted with a backslash to prevent its
				3400	being considered part of a brace expression.
				3401	To avoid conflicts with parameter expansion, the string <B>${</B>
				3402	is not considered eligible for brace expansion.
				3403	<P>
				3404
				3405	This construct is typically used as shorthand when the common
				3406	prefix of the strings to be generated is longer than in the
				3407	above example:
				3408	<DL COMPACT><DT><DD>
				3409	<P>
				3410
				3411	mkdir /usr/local/src/bash/{old,new,dist,bugs}
				3412	</DL>
				3413
				3414	or
				3415	<DL COMPACT><DT><DD>
				3416	chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}}
				3417	</DL>
				3418
				3419	<P>
				3420
				3421	Brace expansion introduces a slight incompatibility with
				3422	historical versions of
				3423	<B>sh</B>.
				3424
				3425	<B>sh</B>
				3426
				3427	does not treat opening or closing braces specially when they
				3428	appear as part of a word, and preserves them in the output.
				3429	<B>Bash</B>
				3430
				3431	removes braces from words as a consequence of brace
				3432	expansion. For example, a word entered to
				3433	<B>sh</B>
				3434
				3435	as <I>file{1,2}</I>
				3436	appears identically in the output. The same word is
				3437	output as
				3438	<I>file1 file2</I>
				3439
				3440	after expansion by
				3441	<B>bash</B>.
				3442
				3443	If strict compatibility with
				3444	<B>sh</B>
				3445
				3446	is desired, start
				3447	<B>bash</B>
				3448
				3449	with the
				3450	<B>+B </B>
				3451
				3452	option or disable brace expansion with the
				3453	<B>+B</B>
				3454
				3455	option to the
				3456	<B>set</B>
				3457
				3458	command (see
				3459	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				3460
				3461	</FONT>
				3462	below).
				3463	<A NAME="lbBA"> </A>
				3464	<H4>Tilde Expansion</H4>
				3465
				3466	<P>
				3467
				3468	If a word begins with an unquoted tilde character (`<B>~</B>'), all of
				3469	the characters preceding the first unquoted slash (or all characters,
				3470	if there is no unquoted slash) are considered a <I>tilde-prefix</I>.
				3471	If none of the characters in the tilde-prefix are quoted, the
				3472	characters in the tilde-prefix following the tilde are treated as a
				3473	possible <I>login name</I>.
				3474	If this login name is the null string, the tilde is replaced with the
				3475	value of the shell parameter
				3476	<FONT SIZE=-1><B>HOME</B>.
				3477
				3478	</FONT>
				3479	If
				3480	<FONT SIZE=-1><B>HOME</B>
				3481
				3482	</FONT>
				3483	is unset, the home directory of the user executing the shell is
				3484	substituted instead.
				3485	Otherwise, the tilde-prefix is replaced with the home directory
				3486	associated with the specified login name.
				3487	<P>
				3488
				3489	If the tilde-prefix is a `~+', the value of the shell variable
				3490	<FONT SIZE=-1><B>PWD</B>
				3491
				3492	</FONT>
				3493	replaces the tilde-prefix.
				3494	If the tilde-prefix is a `~-', the value of the shell variable
				3495	<FONT SIZE=-1><B>OLDPWD</B>,
				3496
				3497	</FONT>
				3498	if it is set, is substituted.
				3499	If the characters following the tilde in the tilde-prefix consist
				3500	of a number <I>N</I>, optionally prefixed
				3501	by a `+' or a `-', the tilde-prefix is replaced with the corresponding
				3502	element from the directory stack, as it would be displayed by the
				3503	<B>dirs</B>
				3504
				3505	builtin invoked with the tilde-prefix as an argument.
				3506	If the characters following the tilde in the tilde-prefix consist of a
				3507	number without a leading `+' or `-', `+' is assumed.
				3508	<P>
				3509
				3510	If the login name is invalid, or the tilde expansion fails, the word
				3511	is unchanged.
				3512	<P>
				3513
				3514	Each variable assignment is checked for unquoted tilde-prefixes immediately
				3515	following a
				3516	<B>:</B>
				3517
				3518	or the first
				3519	<B>=</B>.
				3520
				3521	In these cases, tilde expansion is also performed.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3522	Consequently, one may use filenames with tildes in assignments to
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3523	<FONT SIZE=-1><B>PATH</B>,
				3524
				3525	</FONT>
				3526	<FONT SIZE=-1><B>MAILPATH</B>,
				3527
				3528	</FONT>
				3529	and
				3530	<FONT SIZE=-1><B>CDPATH</B>,
				3531
				3532	</FONT>
				3533	and the shell assigns the expanded value.
				3534	<A NAME="lbBB"> </A>
				3535	<H4>Parameter Expansion</H4>
				3536
				3537	<P>
				3538
				3539	The `<B>$</B>' character introduces parameter expansion,
				3540	command substitution, or arithmetic expansion. The parameter name
				3541	or symbol to be expanded may be enclosed in braces, which
				3542	are optional but serve to protect the variable to be expanded from
				3543	characters immediately following it which could be
				3544	interpreted as part of the name.
				3545	<P>
				3546
				3547	When braces are used, the matching ending brace is the first `<B>}</B>'
				3548	not escaped by a backslash or within a quoted string, and not within an
				3549	embedded arithmetic expansion, command substitution, or parameter
				3550	expansion.
				3551	<P>
				3552
				3553
				3554	<DL COMPACT>
				3555	<DT>${<I>parameter</I>}<DD>
				3556	The value of <I>parameter</I> is substituted. The braces are required
				3557	when
				3558	<I>parameter</I>
				3559
				3560	is a positional parameter with more than one digit,
				3561	or when
				3562	<I>parameter</I>
				3563
				3564	is followed by a character which is not to be
				3565	interpreted as part of its name.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3566	The <I>parameter</I> is a shell parameter as described above
				3567	<B>PARAMETERS</B>) or an array reference (<B>Arrays</B>).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3568
				3569	</DL>
				3570	<P>
				3571
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	3572	If the first character of <I>parameter</I> is an exclamation point (<B>!</B>),
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3573	it introduces a level of variable indirection.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3574	<B>Bash</B> uses the value of the variable formed from the rest of
				3575	<I>parameter</I> as the name of the variable; this variable is then
				3576	expanded and that value is used in the rest of the substitution, rather
				3577	than the value of <I>parameter</I> itself.
				3578	This is known as <I>indirect expansion</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3579	The exceptions to this are the expansions of ${<B>!</B><I>prefix</I><B>*</B>} and
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3580	${<B>!</B><I>name</I>[<I>@</I>]} described below.
				3581	The exclamation point must immediately follow the left brace in order to
				3582	introduce indirection.
				3583	<P>
				3584
				3585	In each of the cases below, <I>word</I> is subject to tilde expansion,
				3586	parameter expansion, command substitution, and arithmetic expansion.
				3587	<P>
				3588
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3589	When not performing substring expansion, using the forms documented below
				3590	(e.g., <B>:-</B>),
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3591	<B>bash</B> tests for a parameter that is unset or null. Omitting the colon
				3592	results in a test only for a parameter that is unset.
				3593	<P>
				3594
				3595
				3596	<DL COMPACT>
				3597	<DT>${<I>parameter</I><B>:-</B><I>word</I>}<DD>
				3598	<B>Use Default Values</B>. If
				3599	<I>parameter</I>
				3600
				3601	is unset or null, the expansion of
				3602	<I>word</I>
				3603
				3604	is substituted. Otherwise, the value of
				3605	<I>parameter</I>
				3606
				3607	is substituted.
				3608	<DT>${<I>parameter</I><B>:=</B><I>word</I>}<DD>
				3609	<B>Assign Default Values</B>.
				3610	If
				3611	<I>parameter</I>
				3612
				3613	is unset or null, the expansion of
				3614	<I>word</I>
				3615
				3616	is assigned to
				3617	<I>parameter</I>.
				3618
				3619	The value of
				3620	<I>parameter</I>
				3621
				3622	is then substituted. Positional parameters and special parameters may
				3623	not be assigned to in this way.
				3624	<DT>${<I>parameter</I><B>:?</B><I>word</I>}<DD>
				3625	<B>Display Error if Null or Unset</B>.
				3626	If
				3627	<I>parameter</I>
				3628
				3629	is null or unset, the expansion of <I>word</I> (or a message to that effect
				3630	if
				3631	<I>word</I>
				3632
				3633	is not present) is written to the standard error and the shell, if it
				3634	is not interactive, exits. Otherwise, the value of <I>parameter</I> is
				3635	substituted.
				3636	<DT>${<I>parameter</I><B>:+</B><I>word</I>}<DD>
				3637	<B>Use Alternate Value</B>.
				3638	If
				3639	<I>parameter</I>
				3640
				3641	is null or unset, nothing is substituted, otherwise the expansion of
				3642	<I>word</I>
				3643
				3644	is substituted.
				3645	<DT>${<I>parameter</I><B>:</B><I>offset</I>}<DD>
				3646
				3647	<DT>${<I>parameter</I><B>:</B><I>offset</I><B>:</B><I>length</I>}<DD>
				3648
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3649	<B>Substring Expansion</B>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3650	Expands to up to <I>length</I> characters of the value of <I>parameter</I>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3651	starting at the character specified by <I>offset</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3652	If <I>parameter</I> is <B>@</B>, an indexed array subscripted by
				3653	<B>@</B> or <B>*</B>, or an associative array name, the results differ as
				3654	described below.
				3655	If <I>length</I> is omitted, expands to the substring of the value of
				3656	<I>parameter</I> starting at the character specified by <I>offset</I>
				3657	and extending to the end of the value.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3658	<I>length</I> and <I>offset</I> are arithmetic expressions (see
				3659	<FONT SIZE=-1><B>ARITHMETIC EVALUATION</B>
				3660
				3661	</FONT>
				3662	below).
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3663	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3664	If <I>offset</I> evaluates to a number less than zero, the value
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3665	is used as an offset in characters
				3666	from the end of the value of <I>parameter</I>.
				3667	If <I>length</I> evaluates to a number less than zero,
				3668	it is interpreted as an offset in characters
				3669	from the end of the value of <I>parameter</I> rather than
				3670	a number of characters, and the expansion is the characters between
				3671	<I>offset</I> and that result.
				3672	Note that a negative offset must be separated from the colon by at least
				3673	one space to avoid being confused with the <B>:-</B> expansion.
				3674	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3675	If <I>parameter</I> is <B>@</B>, the result is <I>length</I> positional
				3676	parameters beginning at <I>offset</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3677	A negative <I>offset</I> is taken relative to one greater than the greatest
				3678	positional parameter, so an offset of -1 evaluates to the last positional
				3679	parameter.
				3680	It is an expansion error if <I>length</I> evaluates to a number less than
				3681	zero.
				3682	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3683	If <I>parameter</I> is an indexed array name subscripted by @ or *,
				3684	the result is the <I>length</I>
				3685	members of the array beginning with ${<I>parameter</I>[<I>offset</I>]}.
				3686	A negative <I>offset</I> is taken relative to one greater than the maximum
				3687	index of the specified array.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3688	It is an expansion error if <I>length</I> evaluates to a number less than
				3689	zero.
				3690	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3691	Substring expansion applied to an associative array produces undefined
				3692	results.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3693	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3694	Substring indexing is zero-based unless the positional parameters
				3695	are used, in which case the indexing starts at 1 by default.
				3696	If <I>offset</I> is 0, and the positional parameters are used, <B>$0</B> is
				3697	prefixed to the list.
				3698	<DT>${<B>!</B><I>prefix</I><B>*</B>}<DD>
				3699
				3700	<DT>${<B>!</B><I>prefix</I><B>@</B>}<DD>
				3701
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3702	<B>Names matching prefix</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3703	Expands to the names of variables whose names begin with <I>prefix</I>,
				3704	separated by the first character of the
				3705	<FONT SIZE=-1><B>IFS</B>
				3706
				3707	</FONT>
				3708	special variable.
				3709	When <I>@</I> is used and the expansion appears within double quotes, each
				3710	variable name expands to a separate word.
				3711	<DT>${<B>!</B><I>name</I>[<I>@</I>]}<DD>
				3712
				3713	<DT>${<B>!</B><I>name</I>[<I>*</I>]}<DD>
				3714
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3715	<B>List of array keys</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3716	If <I>name</I> is an array variable, expands to the list of array indices
				3717	(keys) assigned in <I>name</I>.
				3718	If <I>name</I> is not an array, expands to 0 if <I>name</I> is set and null
				3719	otherwise.
				3720	When <I>@</I> is used and the expansion appears within double quotes, each
				3721	key expands to a separate word.
				3722	<DT>${<B>#</B><I>parameter</I>}<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3723	<B>Parameter length</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3724	The length in characters of the value of <I>parameter</I> is substituted.
				3725	If
				3726	<I>parameter</I>
				3727
				3728	is
				3729	<B>*</B>
				3730
				3731	or
				3732	<B>@</B>,
				3733
				3734	the value substituted is the number of positional parameters.
				3735	If
				3736	<I>parameter</I>
				3737
				3738	is an array name subscripted by
				3739	<B>*</B>
				3740
				3741	or
				3742	<B>@</B>,
				3743
				3744	the value substituted is the number of elements in the array.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3745	If
				3746	<I>parameter</I>
				3747
				3748	is an indexed array name subscripted by a negative number, that number is
				3749	interpreted as relative to one greater than the maximum index of
				3750	<I>parameter</I>, so negative indices count back from the end of the
				3751	array, and an index of -1 references the last element.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3752	<DT>${<I>parameter</I><B>#</B><I>word</I>}<DD>
				3753
				3754	<DT>${<I>parameter</I><B>##</B><I>word</I>}<DD>
				3755
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3756	<B>Remove matching prefix pattern</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3757	The
				3758	<I>word</I>
				3759
				3760	is expanded to produce a pattern just as in pathname
				3761	expansion. If the pattern matches the beginning of
				3762	the value of
				3763	<I>parameter</I>,
				3764
				3765	then the result of the expansion is the expanded value of
				3766	<I>parameter</I>
				3767
				3768	with the shortest matching pattern (the ``<B>#</B>'' case) or the
				3769	longest matching pattern (the ``<B>##</B>'' case) deleted.
				3770	If
				3771	<I>parameter</I>
				3772
				3773	is
				3774	<B>@</B>
				3775
				3776	or
				3777	<B>*</B>,
				3778
				3779	the pattern removal operation is applied to each positional
				3780	parameter in turn, and the expansion is the resultant list.
				3781	If
				3782	<I>parameter</I>
				3783
				3784	is an array variable subscripted with
				3785	<B>@</B>
				3786
				3787	or
				3788	<B>*</B>,
				3789
				3790	the pattern removal operation is applied to each member of the
				3791	array in turn, and the expansion is the resultant list.
				3792	<DT>${<I>parameter</I><B>%</B><I>word</I>}<DD>
				3793
				3794	<DT>${<I>parameter</I><B>%%</B><I>word</I>}<DD>
				3795
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3796	<B>Remove matching suffix pattern</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3797	The <I>word</I> is expanded to produce a pattern just as in
				3798	pathname expansion.
				3799	If the pattern matches a trailing portion of the expanded value of
				3800	<I>parameter</I>,
				3801
				3802	then the result of the expansion is the expanded value of
				3803	<I>parameter</I>
				3804
				3805	with the shortest matching pattern (the ``<B>%</B>'' case) or the
				3806	longest matching pattern (the ``<B>%%</B>'' case) deleted.
				3807	If
				3808	<I>parameter</I>
				3809
				3810	is
				3811	<B>@</B>
				3812
				3813	or
				3814	<B>*</B>,
				3815
				3816	the pattern removal operation is applied to each positional
				3817	parameter in turn, and the expansion is the resultant list.
				3818	If
				3819	<I>parameter</I>
				3820
				3821	is an array variable subscripted with
				3822	<B>@</B>
				3823
				3824	or
				3825	<B>*</B>,
				3826
				3827	the pattern removal operation is applied to each member of the
				3828	array in turn, and the expansion is the resultant list.
				3829	<DT>${<I>parameter</I><B>/</B><I>pattern</I><B>/</B><I>string</I>}<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3830	<B>Pattern substitution</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3831	The <I>pattern</I> is expanded to produce a pattern just as in
				3832	pathname expansion.
				3833	<I>Parameter</I> is expanded and the longest match of <I>pattern</I>
				3834	against its value is replaced with <I>string</I>.
				3835	If <I>pattern</I> begins with <B>/</B>, all matches of <I>pattern</I> are
				3836	replaced with <I>string</I>. Normally only the first match is replaced.
				3837	If <I>pattern</I> begins with <B>#</B>, it must match at the beginning
				3838	of the expanded value of <I>parameter</I>.
				3839	If <I>pattern</I> begins with <B>%</B>, it must match at the end
				3840	of the expanded value of <I>parameter</I>.
				3841	If <I>string</I> is null, matches of <I>pattern</I> are deleted
				3842	and the <B>/</B> following <I>pattern</I> may be omitted.
				3843	If
				3844	<I>parameter</I>
				3845
				3846	is
				3847	<B>@</B>
				3848
				3849	or
				3850	<B>*</B>,
				3851
				3852	the substitution operation is applied to each positional
				3853	parameter in turn, and the expansion is the resultant list.
				3854	If
				3855	<I>parameter</I>
				3856
				3857	is an array variable subscripted with
				3858	<B>@</B>
				3859
				3860	or
				3861	<B>*</B>,
				3862
				3863	the substitution operation is applied to each member of the
				3864	array in turn, and the expansion is the resultant list.
				3865	<DT>${<I>parameter</I><B>^</B><I>pattern</I>}<DD>
				3866
				3867	<DT>${<I>parameter</I><B>^^</B><I>pattern</I>}<DD>
				3868	<DT>${<I>parameter</I><B>,</B><I>pattern</I>}<DD>
				3869	<DT>${<I>parameter</I><B>,,</B><I>pattern</I>}<DD>
				3870
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3871	<B>Case modification</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3872	This expansion modifies the case of alphabetic characters in <I>parameter</I>.
				3873	The <I>pattern</I> is expanded to produce a pattern just as in
				3874	pathname expansion.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3875	Each character in the expanded value of <I>parameter</I> is tested against
				3876	<I>pattern</I>, and, if it matches the pattern, its case is converted.
				3877	The pattern should not attempt to match more than one character.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3878	The <B>^</B> operator converts lowercase letters matching <I>pattern</I>
				3879	to uppercase; the <B>,</B> operator converts matching uppercase letters
				3880	to lowercase.
				3881	The <B>^^</B> and <B>,,</B> expansions convert each matched character in the
				3882	expanded value; the <B>^</B> and <B>,</B> expansions match and convert only
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	3883	the first character in the expanded value.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3884	If <I>pattern</I> is omitted, it is treated like a <B>?</B>, which matches
				3885	every character.
				3886	If
				3887	<I>parameter</I>
				3888
				3889	is
				3890	<B>@</B>
				3891
				3892	or
				3893	<B>*</B>,
				3894
				3895	the case modification operation is applied to each positional
				3896	parameter in turn, and the expansion is the resultant list.
				3897	If
				3898	<I>parameter</I>
				3899
				3900	is an array variable subscripted with
				3901	<B>@</B>
				3902
				3903	or
				3904	<B>*</B>,
				3905
				3906	the case modification operation is applied to each member of the
				3907	array in turn, and the expansion is the resultant list.
				3908	</DL>
				3909	<A NAME="lbBC"> </A>
				3910	<H4>Command Substitution</H4>
				3911
				3912	<P>
				3913
				3914	<I>Command substitution</I> allows the output of a command to replace
				3915	the command name. There are two forms:
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3916	<DL COMPACT><DT><DD>
				3917	<P>
				3918
				3919	<B>$(</B><I>command</I><B>)</B>
				3920	</DL>
				3921
				3922	or
				3923	<DL COMPACT><DT><DD>
				3924	<B>`</B><I>command</I><B>`</B>
				3925	</DL>
				3926
				3927	<P>
				3928
				3929	<B>Bash</B>
				3930
				3931	performs the expansion by executing <I>command</I> and
				3932	replacing the command substitution with the standard output of the
				3933	command, with any trailing newlines deleted.
				3934	Embedded newlines are not deleted, but they may be removed during
				3935	word splitting.
				3936	The command substitution <B>$(cat </B><I>file</I>) can be replaced by
				3937	the equivalent but faster <B>$(< </B><I>file</I>).
				3938	<P>
				3939
				3940	When the old-style backquote form of substitution is used,
				3941	backslash retains its literal meaning except when followed by
				3942	<B>$</B>,
				3943
				3944	<B>`</B>,
				3945
				3946	or
				3947	<B>\</B>.
				3948
				3949	The first backquote not preceded by a backslash terminates the
				3950	command substitution.
				3951	When using the $(<I>command</I>) form, all characters between the
				3952	parentheses make up the command; none are treated specially.
				3953	<P>
				3954
				3955	Command substitutions may be nested. To nest when using the backquoted form,
				3956	escape the inner backquotes with backslashes.
				3957	<P>
				3958
				3959	If the substitution appears within double quotes, word splitting and
				3960	pathname expansion are not performed on the results.
				3961	<A NAME="lbBD"> </A>
				3962	<H4>Arithmetic Expansion</H4>
				3963
				3964	<P>
				3965
				3966	Arithmetic expansion allows the evaluation of an arithmetic expression
				3967	and the substitution of the result. The format for arithmetic expansion is:
				3968	<DL COMPACT><DT><DD>
				3969	<P>
				3970
				3971	<B>$((</B><I>expression</I><B>))</B>
				3972	</DL>
				3973
				3974	<P>
				3975
				3976	The
				3977	<I>expression</I>
				3978
				3979	is treated as if it were within double quotes, but a double quote
				3980	inside the parentheses is not treated specially.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	3981	All tokens in the expression undergo parameter and variable expansion,
				3982	command substitution, and quote removal.
				3983	The result is treated as the arithmetic expression to be evaluated.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	3984	Arithmetic expansions may be nested.
				3985	<P>
				3986
				3987	The evaluation is performed according to the rules listed below under
				3988	<FONT SIZE=-1><B>ARITHMETIC EVALUATION</B>.
				3989
				3990	</FONT>
				3991	If
				3992	<I>expression</I>
				3993
				3994	is invalid,
				3995	<B>bash</B>
				3996
				3997	prints a message indicating failure and no substitution occurs.
				3998	<A NAME="lbBE"> </A>
				3999	<H4>Process Substitution</H4>
				4000
				4001	<P>
				4002
				4003	<I>Process substitution</I> is supported on systems that support named
				4004	pipes (<I>FIFOs</I>) or the <B>/dev/fd</B> method of naming open files.
				4005	It takes the form of
				4006	<B><(</B><I>list</I><B>)</B>
				4007	or
				4008	<B>>(</B><I>list</I><B>)</B>.
				4009	The process <I>list</I> is run with its input or output connected to a
				4010	<I>FIFO</I> or some file in <B>/dev/fd</B>. The name of this file is
				4011	passed as an argument to the current command as the result of the
				4012	expansion. If the <B>>(</B><I>list</I><B>)</B> form is used, writing to
				4013	the file will provide input for <I>list</I>. If the
				4014	<B><(</B><I>list</I><B>)</B> form is used, the file passed as an
				4015	argument should be read to obtain the output of <I>list</I>.
				4016	<P>
				4017
				4018	When available, process substitution is performed
				4019	simultaneously with parameter and variable expansion,
				4020	command substitution,
				4021	and arithmetic expansion.
				4022	<A NAME="lbBF"> </A>
				4023	<H4>Word Splitting</H4>
				4024
				4025	<P>
				4026
				4027	The shell scans the results of
				4028	parameter expansion,
				4029	command substitution,
				4030	and
				4031	arithmetic expansion
				4032	that did not occur within double quotes for
				4033	<I>word splitting</I>.
				4034
				4035	<P>
				4036
				4037	The shell treats each character of
				4038	<FONT SIZE=-1><B>IFS</B>
				4039
				4040	</FONT>
				4041	as a delimiter, and splits the results of the other
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4042	expansions into words using these characters as field terminators.
				4043	If
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4044	<FONT SIZE=-1><B>IFS</B>
				4045
				4046	</FONT>
				4047	is unset, or its
				4048	value is exactly
				4049	<B><space><tab><newline></B>,
				4050
				4051	the default, then
				4052	sequences of
				4053	<B><space></B>,
				4054
				4055	<B><tab></B>,
				4056
				4057	and
				4058	<B><newline></B>
				4059
				4060	at the beginning and end of the results of the previous
				4061	expansions are ignored, and
				4062	any sequence of
				4063	<FONT SIZE=-1><B>IFS</B>
				4064
				4065	</FONT>
				4066	characters not at the beginning or end serves to delimit words.
				4067	If
				4068	<FONT SIZE=-1><B>IFS</B>
				4069
				4070	</FONT>
				4071	has a value other than the default, then sequences of
				4072	the whitespace characters
				4073	<B>space</B>
				4074
				4075	and
				4076	<B>tab</B>
				4077
				4078	are ignored at the beginning and end of the
				4079	word, as long as the whitespace character is in the
				4080	value of
				4081	<FONT SIZE=-1><B>IFS</B>
				4082
				4083	</FONT>
				4084	(an
				4085	<FONT SIZE=-1><B>IFS</B>
				4086
				4087	</FONT>
				4088	whitespace character).
				4089	Any character in
				4090	<FONT SIZE=-1><B>IFS</B>
				4091
				4092	</FONT>
				4093	that is not
				4094	<FONT SIZE=-1><B>IFS</B>
				4095
				4096	</FONT>
				4097	whitespace, along with any adjacent
				4098	<FONT SIZE=-1><B>IFS</B>
				4099
				4100	</FONT>
				4101	whitespace characters, delimits a field.
				4102	A sequence of
				4103	<FONT SIZE=-1><B>IFS</B>
				4104
				4105	</FONT>
				4106	whitespace characters is also treated as a delimiter.
				4107	If the value of
				4108	<FONT SIZE=-1><B>IFS</B>
				4109
				4110	</FONT>
				4111	is null, no word splitting occurs.
				4112	<P>
				4113
				4114	Explicit null arguments (<B>""</B> or <B>aqaq</B>) are retained.
				4115	Unquoted implicit null arguments, resulting from the expansion of
				4116	parameters that have no values, are removed.
				4117	If a parameter with no value is expanded within double quotes, a
				4118	null argument results and is retained.
				4119	<P>
				4120
				4121	Note that if no expansion occurs, no splitting
				4122	is performed.
				4123	<A NAME="lbBG"> </A>
				4124	<H4>Pathname Expansion</H4>
				4125
				4126	<P>
				4127
				4128	After word splitting,
				4129	unless the
				4130	<B>-f</B>
				4131
				4132	option has been set,
				4133	<B>bash</B>
				4134
				4135	scans each word for the characters
				4136	<B>*</B>,
				4137
				4138	<B>?</B>,
				4139
				4140	and
				4141	<B>[</B>.
				4142
				4143	If one of these characters appears, then the word is
				4144	regarded as a
				4145	<I>pattern</I>,
				4146
				4147	and replaced with an alphabetically sorted list of
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4148	filenames matching the pattern
				4149	(see
				4150	<FONT SIZE=-1><B>Pattern Matching</B>
				4151
				4152	</FONT>
				4153	below).
				4154	If no matching filenames are found,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4155	and the shell option
				4156	<B>nullglob</B>
				4157
				4158	is not enabled, the word is left unchanged.
				4159	If the
				4160	<B>nullglob</B>
				4161
				4162	option is set, and no matches are found,
				4163	the word is removed.
				4164	If the
				4165	<B>failglob</B>
				4166
				4167	shell option is set, and no matches are found, an error message
				4168	is printed and the command is not executed.
				4169	If the shell option
				4170	<B>nocaseglob</B>
				4171
				4172	is enabled, the match is performed without regard to the case
				4173	of alphabetic characters.
				4174	When a pattern is used for pathname expansion,
				4175	the character
				4176	<B>``.''</B>
				4177
				4178	at the start of a name or immediately following a slash
				4179	must be matched explicitly, unless the shell option
				4180	<B>dotglob</B>
				4181
				4182	is set.
				4183	When matching a pathname, the slash character must always be
				4184	matched explicitly.
				4185	In other cases, the
				4186	<B>``.''</B>
				4187
				4188	character is not treated specially.
				4189	See the description of
				4190	<B>shopt</B>
				4191
				4192	below under
				4193	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				4194
				4195	</FONT>
				4196	for a description of the
				4197	<B>nocaseglob</B>,
				4198
				4199	<B>nullglob</B>,
				4200
				4201	<B>failglob</B>,
				4202
				4203	and
				4204	<B>dotglob</B>
				4205
				4206	shell options.
				4207	<P>
				4208
				4209	The
				4210	<FONT SIZE=-1><B>GLOBIGNORE</B>
				4211
				4212	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4213	shell variable may be used to restrict the set of filenames matching a
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4214	<I>pattern</I>.
				4215
				4216	If
				4217	<FONT SIZE=-1><B>GLOBIGNORE</B>
				4218
				4219	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4220	is set, each matching filename that also matches one of the patterns in
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4221	<FONT SIZE=-1><B>GLOBIGNORE</B>
				4222
				4223	</FONT>
				4224	is removed from the list of matches.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4225	The filenames
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4226	<B>``.''</B>
				4227
				4228	and
				4229	<B>``..''</B>
				4230
				4231	are always ignored when
				4232	<FONT SIZE=-1><B>GLOBIGNORE</B>
				4233
				4234	</FONT>
				4235	is set and not null. However, setting
				4236	<FONT SIZE=-1><B>GLOBIGNORE</B>
				4237
				4238	</FONT>
				4239	to a non-null value has the effect of enabling the
				4240	<B>dotglob</B>
				4241
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4242	shell option, so all other filenames beginning with a
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4243	<B>``.''</B>
				4244
				4245	will match.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4246	To get the old behavior of ignoring filenames beginning with a
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4247	<B>``.''</B>,
				4248
				4249	make
				4250	<B>``.*''</B>
				4251
				4252	one of the patterns in
				4253	<FONT SIZE=-1><B>GLOBIGNORE</B>.
				4254
				4255	</FONT>
				4256	The
				4257	<B>dotglob</B>
				4258
				4259	option is disabled when
				4260	<FONT SIZE=-1><B>GLOBIGNORE</B>
				4261
				4262	</FONT>
				4263	is unset.
				4264	<P>
				4265
				4266	<B>Pattern Matching</B>
				4267	<P>
				4268
				4269	Any character that appears in a pattern, other than the special pattern
				4270	characters described below, matches itself. The NUL character may not
				4271	occur in a pattern. A backslash escapes the following character; the
				4272	escaping backslash is discarded when matching.
				4273	The special pattern characters must be quoted if
				4274	they are to be matched literally.
				4275	<P>
				4276
				4277	The special pattern characters have the following meanings:
				4278	<P>
				4279
				4280
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	4281	<DL COMPACT><DT><DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4282	<DL COMPACT>
				4283	<DT><B>*</B>
				4284
				4285	<DD>
				4286	Matches any string, including the null string.
				4287	When the <B>globstar</B> shell option is enabled, and <B>*</B> is used in
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	4288	a pathname expansion context, two adjacent <B>*</B>s used as a single
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4289	pattern will match all files and zero or more directories and
				4290	subdirectories.
				4291	If followed by a <B>/</B>, two adjacent <B>*</B>s will match only directories
				4292	and subdirectories.
				4293	<DT><B>?</B>
				4294
				4295	<DD>
				4296	Matches any single character.
				4297	<DT><B>[...]</B>
				4298
				4299	<DD>
				4300	Matches any one of the enclosed characters. A pair of characters
				4301	separated by a hyphen denotes a
				4302	<I>range expression</I>;
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4303	any character that falls between those two characters, inclusive,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4304	using the current locale's collating sequence and character set,
				4305	is matched. If the first character following the
				4306	<B>[</B>
				4307
				4308	is a
				4309	<B>!</B>
				4310
				4311	or a
				4312	<B>^</B>
				4313
				4314	then any character not enclosed is matched.
				4315	The sorting order of characters in range expressions is determined by
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4316	the current locale and the values of the
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	4317	<FONT SIZE=-1><B>LC_COLLATE</B>
				4318
				4319	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4320	or
				4321	<FONT SIZE=-1><B>LC_ALL</B>
				4322
				4323	</FONT>
				4324	shell variables, if set.
				4325	To obtain the traditional interpretation of range expressions, where
				4326	<B>[a-d]</B>
				4327
				4328	is equivalent to
				4329	<B>[abcd]</B>,
				4330
				4331	set value of the
				4332	<B>LC_ALL</B>
				4333
				4334	shell variable to
				4335	<B>C</B>,
				4336
				4337	or enable the
				4338	<B>globasciiranges</B>
				4339
				4340	shell option.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4341	A
				4342	<B>-</B>
				4343
				4344	may be matched by including it as the first or last character
				4345	in the set.
				4346	A
				4347	<B>]</B>
				4348
				4349	may be matched by including it as the first character
				4350	in the set.
				4351	<BR>
				4352
				4353	<P>
				4354
				4355
				4356	Within
				4357	<B>[</B>
				4358
				4359	and
				4360	<B>]</B>,
				4361
				4362	<I>character classes</I> can be specified using the syntax
				4363	<B>[:</B><I>class</I><B>:]</B>, where <I>class</I> is one of the
				4364	following classes defined in the POSIX standard:
				4365	</DL>
				4366	<P>
				4367
				4368	<DL COMPACT><DT><DD>
				4369	<B>
				4370	</B>
				4371
				4372	alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdigit
				4373	<BR>
				4374
				4375	A character class matches any character belonging to that class.
				4376	The <B>word</B> character class matches letters, digits, and the character _.
				4377	<BR>
				4378
				4379	<P>
				4380
				4381
				4382	Within
				4383	<B>[</B>
				4384
				4385	and
				4386	<B>]</B>,
				4387
				4388	an <I>equivalence class</I> can be specified using the syntax
				4389	<B>[=</B><I>c</I><B>=]</B>, which matches all characters with the
				4390	same collation weight (as defined by the current locale) as
				4391	the character <I>c</I>.
				4392	<BR>
				4393
				4394	<P>
				4395
				4396
				4397	Within
				4398	<B>[</B>
				4399
				4400	and
				4401	<B>]</B>,
				4402
				4403	the syntax <B>[.</B><I>symbol</I><B>.]</B> matches the collating symbol
				4404	<I>symbol</I>.
				4405	</DL>
				4406
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	4407	</DL>
				4408
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4409
				4410	<P>
				4411
				4412	If the <B>extglob</B> shell option is enabled using the <B>shopt</B>
				4413	builtin, several extended pattern matching operators are recognized.
				4414	In the following description, a <I>pattern-list</I> is a list of one
				4415	or more patterns separated by a <B>\|</B>.
				4416	Composite patterns may be formed using one or more of the following
				4417	sub-patterns:
				4418	<P>
				4419
				4420	<DL COMPACT><DT><DD>
				4421	<DL COMPACT>
				4422	<DT><B>?(</B><I>pattern-list</I><B>)</B><DD>
				4423	Matches zero or one occurrence of the given patterns
				4424	<DT><B>*(</B><I>pattern-list</I><B>)</B><DD>
				4425	Matches zero or more occurrences of the given patterns
				4426	<DT><B>+(</B><I>pattern-list</I><B>)</B><DD>
				4427	Matches one or more occurrences of the given patterns
				4428	<DT><B>@(</B><I>pattern-list</I><B>)</B><DD>
				4429	Matches one of the given patterns
				4430	<DT><B>!(</B><I>pattern-list</I><B>)</B><DD>
				4431	Matches anything except one of the given patterns
				4432	</DL></DL>
				4433
				4434
				4435	<A NAME="lbBH"> </A>
				4436	<H4>Quote Removal</H4>
				4437
				4438	<P>
				4439
				4440	After the preceding expansions, all unquoted occurrences of the
				4441	characters
				4442	<B>\</B>,
				4443
				4444	<B>aq</B>,
				4445
				4446	and <B>"</B> that did not result from one of the above
				4447	expansions are removed.
				4448	<A NAME="lbBI"> </A>
				4449	<H3>REDIRECTION</H3>
				4450
				4451	Before a command is executed, its input and output
				4452	may be
				4453	<I>redirected</I>
				4454
				4455	using a special notation interpreted by the shell.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4456	Redirection allows commands' file handles to be
				4457	duplicated, opened, closed,
				4458	made to refer to different files,
				4459	and can change the files the command reads from and writes to.
				4460	Redirection may also be used to modify file handles in the
				4461	current shell execution environment.
				4462	The following redirection
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4463	operators may precede or appear anywhere within a
				4464	<I>simple command</I>
				4465
				4466	or may follow a
				4467	<I>command</I>.
				4468
				4469	Redirections are processed in the order they appear, from
				4470	left to right.
				4471	<P>
				4472
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	4473	Each redirection that may be preceded by a file descriptor number
				4474	may instead be preceded by a word of the form {<I>varname</I>}.
				4475	In this case, for each redirection operator except
				4476	>&- and <&-, the shell will allocate a file descriptor greater
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4477	than or equal to 10 and assign it to <I>varname</I>.
				4478	If >&- or <&- is preceded
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	4479	by {<I>varname</I>}, the value of <I>varname</I> defines the file
				4480	descriptor to close.
				4481	<P>
				4482
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4483	In the following descriptions, if the file descriptor number is
				4484	omitted, and the first character of the redirection operator is
				4485	<B><</B>,
				4486
				4487	the redirection refers to the standard input (file descriptor
				4488	0). If the first character of the redirection operator is
				4489	<B>></B>,
				4490
				4491	the redirection refers to the standard output (file descriptor
				4492	1).
				4493	<P>
				4494
				4495	The word following the redirection operator in the following
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4496	descriptions, unless otherwise noted, is subjected to
				4497	brace expansion, tilde expansion, parameter and variable expansion,
				4498	command substitution, arithmetic expansion, quote removal,
				4499	pathname expansion, and word splitting.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4500	If it expands to more than one word,
				4501	<B>bash</B>
				4502
				4503	reports an error.
				4504	<P>
				4505
				4506	Note that the order of redirections is significant. For example,
				4507	the command
				4508	<DL COMPACT><DT><DD>
				4509	<P>
				4510
				4511	ls <B>></B> dirlist 2<B>>&</B>1
				4512	</DL>
				4513
				4514	<P>
				4515
				4516	directs both standard output and standard error to the file
				4517	<I>dirlist</I>,
				4518
				4519	while the command
				4520	<DL COMPACT><DT><DD>
				4521	<P>
				4522
				4523	ls 2<B>>&</B>1 <B>></B> dirlist
				4524	</DL>
				4525
				4526	<P>
				4527
				4528	directs only the standard output to file
				4529	<I>dirlist</I>,
				4530
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	4531	because the standard error was duplicated from the standard output
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4532	before the standard output was redirected to
				4533	<I>dirlist</I>.
				4534
				4535	<P>
				4536
				4537	<B>Bash</B> handles several filenames specially when they are used in
				4538	redirections, as described in the following table:
				4539	<DL COMPACT><DT><DD>
				4540	<P>
				4541
				4542
				4543	<DL COMPACT>
				4544	<DT><B>/dev/fd/</B><I>fd</I>
				4545
				4546	<DD>
				4547	If <I>fd</I> is a valid integer, file descriptor <I>fd</I> is duplicated.
				4548	<DT><B>/dev/stdin</B>
				4549
				4550	<DD>
				4551	File descriptor 0 is duplicated.
				4552	<DT><B>/dev/stdout</B>
				4553
				4554	<DD>
				4555	File descriptor 1 is duplicated.
				4556	<DT><B>/dev/stderr</B>
				4557
				4558	<DD>
				4559	File descriptor 2 is duplicated.
				4560	<DT><B>/dev/tcp/</B><I>host</I>/<I>port</I>
				4561
				4562	<DD>
				4563	If <I>host</I> is a valid hostname or Internet address, and <I>port</I>
				4564	is an integer port number or service name, <B>bash</B> attempts to open
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4565	the corresponding TCP socket.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4566	<DT><B>/dev/udp/</B><I>host</I>/<I>port</I>
				4567
				4568	<DD>
				4569	If <I>host</I> is a valid hostname or Internet address, and <I>port</I>
				4570	is an integer port number or service name, <B>bash</B> attempts to open
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4571	the corresponding UDP socket.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4572
				4573	</DL></DL>
				4574
				4575	<P>
				4576
				4577	A failure to open or create a file causes the redirection to fail.
				4578	<P>
				4579
				4580	Redirections using file descriptors greater than 9 should be used with
				4581	care, as they may conflict with file descriptors the shell uses
				4582	internally.
				4583	<A NAME="lbBJ"> </A>
				4584	<H4>Redirecting Input</H4>
				4585
				4586	<P>
				4587
				4588	Redirection of input causes the file whose name results from
				4589	the expansion of
				4590	<I>word</I>
				4591
				4592	to be opened for reading on file descriptor
				4593	<I>n</I>,
				4594
				4595	or the standard input (file descriptor 0) if
				4596	<I>n</I>
				4597
				4598	is not specified.
				4599	<P>
				4600
				4601	The general format for redirecting input is:
				4602	<DL COMPACT><DT><DD>
				4603	<P>
				4604
				4605	[<I>n</I>]<B><</B><I>word</I>
				4606	</DL>
				4607
				4608	<A NAME="lbBK"> </A>
				4609	<H4>Redirecting Output</H4>
				4610
				4611	<P>
				4612
				4613	Redirection of output causes the file whose name results from
				4614	the expansion of
				4615	<I>word</I>
				4616
				4617	to be opened for writing on file descriptor
				4618	<I>n</I>,
				4619
				4620	or the standard output (file descriptor 1) if
				4621	<I>n</I>
				4622
				4623	is not specified. If the file does not exist it is created;
				4624	if it does exist it is truncated to zero size.
				4625	<P>
				4626
				4627	The general format for redirecting output is:
				4628	<DL COMPACT><DT><DD>
				4629	<P>
				4630
				4631	[<I>n</I>]<B>></B><I>word</I>
				4632	</DL>
				4633
				4634	<P>
				4635
				4636	If the redirection operator is
				4637	<B>></B>,
				4638
				4639	and the
				4640	<B>noclobber</B>
				4641
				4642	option to the
				4643	<B>set</B>
				4644
				4645	builtin has been enabled, the redirection will fail if the file
				4646	whose name results from the expansion of <I>word</I> exists and is
				4647	a regular file.
				4648	If the redirection operator is
				4649	<B>>\|</B>,
				4650
				4651	or the redirection operator is
				4652	<B>></B>
				4653
				4654	and the
				4655	<B>noclobber</B>
				4656
				4657	option to the
				4658	<B>set</B>
				4659
				4660	builtin command is not enabled, the redirection is attempted even
				4661	if the file named by <I>word</I> exists.
				4662	<A NAME="lbBL"> </A>
				4663	<H4>Appending Redirected Output</H4>
				4664
				4665	<P>
				4666
				4667	Redirection of output in this fashion
				4668	causes the file whose name results from
				4669	the expansion of
				4670	<I>word</I>
				4671
				4672	to be opened for appending on file descriptor
				4673	<I>n</I>,
				4674
				4675	or the standard output (file descriptor 1) if
				4676	<I>n</I>
				4677
				4678	is not specified. If the file does not exist it is created.
				4679	<P>
				4680
				4681	The general format for appending output is:
				4682	<DL COMPACT><DT><DD>
				4683	<P>
				4684
				4685	[<I>n</I>]<B>>></B><I>word</I>
				4686	</DL>
				4687
				4688	<P>
				4689
				4690	<A NAME="lbBM"> </A>
				4691	<H4>Redirecting Standard Output and Standard Error</H4>
				4692
				4693	<P>
				4694
				4695	This construct allows both the
				4696	standard output (file descriptor 1) and
				4697	the standard error output (file descriptor 2)
				4698	to be redirected to the file whose name is the
				4699	expansion of
				4700	<I>word</I>.
				4701
				4702	<P>
				4703
				4704	There are two formats for redirecting standard output and
				4705	standard error:
				4706	<DL COMPACT><DT><DD>
				4707	<P>
				4708
				4709	<B>&></B><I>word</I>
				4710	</DL>
				4711
				4712	and
				4713	<DL COMPACT><DT><DD>
				4714	<B>>&</B><I>word</I>
				4715	</DL>
				4716
				4717	<P>
				4718
				4719	Of the two forms, the first is preferred.
				4720	This is semantically equivalent to
				4721	<DL COMPACT><DT><DD>
				4722	<P>
				4723
				4724	<B>></B><I>word</I> 2<B>>&</B>1
				4725	</DL>
				4726
				4727	<P>
				4728
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4729	When using the second form, <I>word</I> may not expand to a number or
				4730	<B>-</B>. If it does, other redirection operators apply
				4731	(see <B>Duplicating File Descriptors</B> below) for compatibility
				4732	reasons.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4733	<A NAME="lbBN"> </A>
				4734	<H4>Appending Standard Output and Standard Error</H4>
				4735
				4736	<P>
				4737
				4738	This construct allows both the
				4739	standard output (file descriptor 1) and
				4740	the standard error output (file descriptor 2)
				4741	to be appended to the file whose name is the
				4742	expansion of
				4743	<I>word</I>.
				4744
				4745	<P>
				4746
				4747	The format for appending standard output and standard error is:
				4748	<DL COMPACT><DT><DD>
				4749	<P>
				4750
				4751	<B>&>></B><I>word</I>
				4752	</DL>
				4753
				4754	<P>
				4755
				4756	This is semantically equivalent to
				4757	<DL COMPACT><DT><DD>
				4758	<P>
				4759
				4760	<B>>></B><I>word</I> 2<B>>&</B>1
				4761	</DL>
				4762
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4763	<P>
				4764
				4765	(see <B>Duplicating File Descriptors</B> below).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4766	<A NAME="lbBO"> </A>
				4767	<H4>Here Documents</H4>
				4768
				4769	<P>
				4770
				4771	This type of redirection instructs the shell to read input from the
				4772	current source until a line containing only
				4773	<I>delimiter</I>
				4774
				4775	(with no trailing blanks)
				4776	is seen. All of
				4777	the lines read up to that point are then used as the standard
				4778	input for a command.
				4779	<P>
				4780
				4781	The format of here-documents is:
				4782	<DL COMPACT><DT><DD>
				4783	<P>
				4784
				4785	<PRE>
				4786	<B><<</B>[<B>-</B>]<I>word</I>
				4787	<I>here-document</I>
				4788	<I>delimiter</I>
				4789	</PRE>
				4790
				4791	</DL>
				4792
				4793	<P>
				4794
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4795	No parameter and variable expansion, command substitution,
				4796	arithmetic expansion, or pathname expansion is performed on
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4797	<I>word</I>.
				4798
				4799	If any characters in
				4800	<I>word</I>
				4801
				4802	are quoted, the
				4803	<I>delimiter</I>
				4804
				4805	is the result of quote removal on
				4806	<I>word</I>,
				4807
				4808	and the lines in the here-document are not expanded.
				4809	If <I>word</I> is unquoted,
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4810	all lines of the here-document are subjected to
				4811	parameter expansion, command substitution, and arithmetic expansion,
				4812	the character sequence
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4813	<B>\<newline></B>
				4814
				4815	is ignored, and
				4816	<B>\</B>
				4817
				4818	must be used to quote the characters
				4819	<B>\</B>,
				4820
				4821	<B>$</B>,
				4822
				4823	and
				4824	<B>`</B>.
				4825
				4826	<P>
				4827
				4828	If the redirection operator is
				4829	<B><<-</B>,
				4830
				4831	then all leading tab characters are stripped from input lines and the
				4832	line containing
				4833	<I>delimiter</I>.
				4834
				4835	This allows
				4836	here-documents within shell scripts to be indented in a
				4837	natural fashion.
				4838	<A NAME="lbBP"> </A>
				4839	<H4>Here Strings</H4>
				4840
				4841	A variant of here documents, the format is:
				4842	<DL COMPACT><DT><DD>
				4843	<P>
				4844
				4845	<PRE>
				4846	<B><<<</B><I>word</I>
				4847	</PRE>
				4848
				4849	</DL>
				4850
				4851	<P>
				4852
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4853	The <I>word</I> undergoes
				4854	brace expansion, tilde expansion, parameter and variable expansion,
				4855	command substitution, arithmetic expansion, and quote removal.
				4856	Pathname expansion and word splitting are not performed.
				4857	The result is supplied as a single string to the command on its
				4858	standard input.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4859	<A NAME="lbBQ"> </A>
				4860	<H4>Duplicating File Descriptors</H4>
				4861
				4862	<P>
				4863
				4864	The redirection operator
				4865	<DL COMPACT><DT><DD>
				4866	<P>
				4867
				4868	[<I>n</I>]<B><&</B><I>word</I>
				4869	</DL>
				4870
				4871	<P>
				4872
				4873	is used to duplicate input file descriptors.
				4874	If
				4875	<I>word</I>
				4876
				4877	expands to one or more digits, the file descriptor denoted by
				4878	<I>n</I>
				4879
				4880	is made to be a copy of that file descriptor.
				4881	If the digits in
				4882	<I>word</I>
				4883
				4884	do not specify a file descriptor open for input, a redirection error occurs.
				4885	If
				4886	<I>word</I>
				4887
				4888	evaluates to
				4889	<B>-</B>,
				4890
				4891	file descriptor
				4892	<I>n</I>
				4893
				4894	is closed. If
				4895	<I>n</I>
				4896
				4897	is not specified, the standard input (file descriptor 0) is used.
				4898	<P>
				4899
				4900	The operator
				4901	<DL COMPACT><DT><DD>
				4902	<P>
				4903
				4904	[<I>n</I>]<B>>&</B><I>word</I>
				4905	</DL>
				4906
				4907	<P>
				4908
				4909	is used similarly to duplicate output file descriptors. If
				4910	<I>n</I>
				4911
				4912	is not specified, the standard output (file descriptor 1) is used.
				4913	If the digits in
				4914	<I>word</I>
				4915
				4916	do not specify a file descriptor open for output, a redirection error occurs.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4917	If
				4918	<I>word</I>
				4919
				4920	evaluates to
				4921	<B>-</B>,
				4922
				4923	file descriptor
				4924	<I>n</I>
				4925
				4926	is closed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4927	As a special case, if <I>n</I> is omitted, and <I>word</I> does not
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	4928	expand to one or more digits or <B>-</B>, the standard output and standard
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	4929	error are redirected as described previously.
				4930	<A NAME="lbBR"> </A>
				4931	<H4>Moving File Descriptors</H4>
				4932
				4933	<P>
				4934
				4935	The redirection operator
				4936	<DL COMPACT><DT><DD>
				4937	<P>
				4938
				4939	[<I>n</I>]<B><&</B><I>digit</I><B>-</B>
				4940	</DL>
				4941
				4942	<P>
				4943
				4944	moves the file descriptor <I>digit</I> to file descriptor
				4945	<I>n</I>,
				4946
				4947	or the standard input (file descriptor 0) if <I>n</I> is not specified.
				4948	<I>digit</I> is closed after being duplicated to <I>n</I>.
				4949	<P>
				4950
				4951	Similarly, the redirection operator
				4952	<DL COMPACT><DT><DD>
				4953	<P>
				4954
				4955	[<I>n</I>]<B>>&</B><I>digit</I><B>-</B>
				4956	</DL>
				4957
				4958	<P>
				4959
				4960	moves the file descriptor <I>digit</I> to file descriptor
				4961	<I>n</I>,
				4962
				4963	or the standard output (file descriptor 1) if <I>n</I> is not specified.
				4964	<A NAME="lbBS"> </A>
				4965	<H4>Opening File Descriptors for Reading and Writing</H4>
				4966
				4967	<P>
				4968
				4969	The redirection operator
				4970	<DL COMPACT><DT><DD>
				4971	<P>
				4972
				4973	[<I>n</I>]<B><></B><I>word</I>
				4974	</DL>
				4975
				4976	<P>
				4977
				4978	causes the file whose name is the expansion of
				4979	<I>word</I>
				4980
				4981	to be opened for both reading and writing on file descriptor
				4982	<I>n</I>,
				4983
				4984	or on file descriptor 0 if
				4985	<I>n</I>
				4986
				4987	is not specified. If the file does not exist, it is created.
				4988	<A NAME="lbBT"> </A>
				4989	<H3>ALIASES</H3>
				4990
				4991	<I>Aliases</I> allow a string to be substituted for a word when it is used
				4992	as the first word of a simple command.
				4993	The shell maintains a list of aliases that may be set and unset with the
				4994	<B>alias</B>
				4995
				4996	and
				4997	<B>unalias</B>
				4998
				4999	builtin commands (see
				5000	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				5001
				5002	</FONT>
				5003	below).
				5004	The first word of each simple command, if unquoted,
				5005	is checked to see if it has an
				5006	alias. If so, that word is replaced by the text of the alias.
				5007	The characters <B>/</B>, <B>$</B>, <B>`</B>, and <B>=</B> and
				5008	any of the shell <I>metacharacters</I> or quoting characters
				5009	listed above may not appear in an alias name.
				5010	The replacement text may contain any valid shell input,
				5011	including shell metacharacters.
				5012	The first word of the replacement text is tested
				5013	for aliases, but a word that is identical to an alias being expanded
				5014	is not expanded a second time.
				5015	This means that one may alias
				5016	<B>ls</B>
				5017
				5018	to
				5019	<B>ls -F</B>,
				5020
				5021	for instance, and
				5022	<B>bash</B>
				5023
				5024	does not try to recursively expand the replacement text.
				5025	If the last character of the alias value is a
				5026	<I>blank</I>,
				5027
				5028	then the next command
				5029	word following the alias is also checked for alias expansion.
				5030	<P>
				5031
				5032	Aliases are created and listed with the
				5033	<B>alias</B>
				5034
				5035	command, and removed with the
				5036	<B>unalias</B>
				5037
				5038	command.
				5039	<P>
				5040
				5041	There is no mechanism for using arguments in the replacement text.
				5042	If arguments are needed, a shell function should be used (see
				5043	<FONT SIZE=-1><B>FUNCTIONS</B>
				5044
				5045	</FONT>
				5046	below).
				5047	<P>
				5048
				5049	Aliases are not expanded when the shell is not interactive, unless
				5050	the
				5051	<B>expand_aliases</B>
				5052
				5053	shell option is set using
				5054	<B>shopt</B>
				5055
				5056	(see the description of
				5057	<B>shopt</B>
				5058
				5059	under
				5060	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B></FONT>
				5061	below).
				5062	<P>
				5063
				5064	The rules concerning the definition and use of aliases are
				5065	somewhat confusing.
				5066	<B>Bash</B>
				5067
				5068	always reads at least one complete line
				5069	of input before executing any
				5070	of the commands on that line. Aliases are expanded when a
				5071	command is read, not when it is executed. Therefore, an
				5072	alias definition appearing on the same line as another
				5073	command does not take effect until the next line of input is read.
				5074	The commands following the alias definition
				5075	on that line are not affected by the new alias.
				5076	This behavior is also an issue when functions are executed.
				5077	Aliases are expanded when a function definition is read,
				5078	not when the function is executed, because a function definition
				5079	is itself a compound command. As a consequence, aliases
				5080	defined in a function are not available until after that
				5081	function is executed. To be safe, always put
				5082	alias definitions on a separate line, and do not use
				5083	<B>alias</B>
				5084
				5085	in compound commands.
				5086	<P>
				5087
				5088	For almost every purpose, aliases are superseded by
				5089	shell functions.
				5090	<A NAME="lbBU"> </A>
				5091	<H3>FUNCTIONS</H3>
				5092
				5093	A shell function, defined as described above under
				5094	<FONT SIZE=-1><B>SHELL GRAMMAR</B>,
				5095
				5096	</FONT>
				5097	stores a series of commands for later execution.
				5098	When the name of a shell function is used as a simple command name,
				5099	the list of commands associated with that function name is executed.
				5100	Functions are executed in the context of the
				5101	current shell; no new process is created to interpret
				5102	them (contrast this with the execution of a shell script).
				5103	When a function is executed, the arguments to the
				5104	function become the positional parameters
				5105	during its execution.
				5106	The special parameter
				5107	<B>#</B>
				5108
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5109	is updated to reflect the change. Special parameter <B>0</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5110	is unchanged.
				5111	The first element of the
				5112	<FONT SIZE=-1><B>FUNCNAME</B>
				5113
				5114	</FONT>
				5115	variable is set to the name of the function while the function
				5116	is executing.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5117	<P>
				5118
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5119	All other aspects of the shell execution
				5120	environment are identical between a function and its caller
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5121	with these exceptions: the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5122	<FONT SIZE=-1><B>DEBUG</B>
				5123
				5124	</FONT>
				5125	and
				5126	<B>RETURN</B>
				5127
				5128	traps (see the description of the
				5129	<B>trap</B>
				5130
				5131	builtin under
				5132	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				5133
				5134	</FONT>
				5135	below) are not inherited unless the function has been given the
				5136	<B>trace</B> attribute (see the description of the
				5137	<FONT SIZE=-1><B>declare</B>
				5138
				5139	</FONT>
				5140	builtin below) or the
				5141	<B>-o functrace</B> shell option has been enabled with
				5142	the <B>set</B> builtin
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5143	(in which case all functions inherit the <B>DEBUG</B> and <B>RETURN</B> traps),
				5144	and the
				5145	<FONT SIZE=-1><B>ERR</B>
				5146
				5147	</FONT>
				5148	trap is not inherited unless the <B>-o errtrace</B> shell option has
				5149	been enabled.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5150	<P>
				5151
				5152	Variables local to the function may be declared with the
				5153	<B>local</B>
				5154
				5155	builtin command. Ordinarily, variables and their values
				5156	are shared between the function and its caller.
				5157	<P>
				5158
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5159	The <B>FUNCNEST</B> variable, if set to a numeric value greater
				5160	than 0, defines a maximum function nesting level. Function
				5161	invocations that exceed the limit cause the entire command to
				5162	abort.
				5163	<P>
				5164
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5165	If the builtin command
				5166	<B>return</B>
				5167
				5168	is executed in a function, the function completes and
				5169	execution resumes with the next command after the function
				5170	call.
				5171	Any command associated with the <B>RETURN</B> trap is executed
				5172	before execution resumes.
				5173	When a function completes, the values of the
				5174	positional parameters and the special parameter
				5175	<B>#</B>
				5176
				5177	are restored to the values they had prior to the function's
				5178	execution.
				5179	<P>
				5180
				5181	Function names and definitions may be listed with the
				5182	<B>-f</B>
				5183
				5184	option to the
				5185	<B>declare</B>
				5186
				5187	or
				5188	<B>typeset</B>
				5189
				5190	builtin commands. The
				5191	<B>-F</B>
				5192
				5193	option to
				5194	<B>declare</B>
				5195
				5196	or
				5197	<B>typeset</B>
				5198
				5199	will list the function names only
				5200	(and optionally the source file and line number, if the <B>extdebug</B>
				5201	shell option is enabled).
				5202	Functions may be exported so that subshells
				5203	automatically have them defined with the
				5204	<B>-f</B>
				5205
				5206	option to the
				5207	<B>export</B>
				5208
				5209	builtin.
				5210	A function definition may be deleted using the <B>-f</B> option to
				5211	the
				5212	<B>unset</B>
				5213
				5214	builtin.
				5215	Note that shell functions and variables with the same name may result
				5216	in multiple identically-named entries in the environment passed to the
				5217	shell's children.
				5218	Care should be taken in cases where this may cause a problem.
				5219	<P>
				5220
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5221	Functions may be recursive.
				5222	The <B>FUNCNEST</B> variable may be used to limit the depth of the
				5223	function call stack and restrict the number of function invocations.
				5224	By default, no limit is imposed on the number of recursive calls.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5225	<A NAME="lbBV"> </A>
				5226	<H3>ARITHMETIC EVALUATION</H3>
				5227
				5228	The shell allows arithmetic expressions to be evaluated, under
				5229	certain circumstances (see the <B>let</B> and <B>declare</B> builtin
				5230	commands and <B>Arithmetic Expansion</B>).
				5231	Evaluation is done in fixed-width integers with no check for overflow,
				5232	though division by 0 is trapped and flagged as an error.
				5233	The operators and their precedence, associativity, and values
				5234	are the same as in the C language.
				5235	The following list of operators is grouped into levels of
				5236	equal-precedence operators.
				5237	The levels are listed in order of decreasing precedence.
				5238	<P>
				5239
				5240
				5241	<DL COMPACT>
				5242	<DT><B></B><I>id</I>++ <I>id</I>--
				5243
				5244	<DD>
				5245	variable post-increment and post-decrement
				5246	<DT><B>++</B><I>id</I> --<I>id</I>
				5247
				5248	<DD>
				5249	variable pre-increment and pre-decrement
				5250	<DT><B>- +</B>
				5251
				5252	<DD>
				5253	unary minus and plus
				5254	<DT><B>! ~</B>
				5255
				5256	<DD>
				5257	logical and bitwise negation
				5258	<DT><B>**</B>
				5259
				5260	<DD>
				5261	exponentiation
				5262	<DT><B>* / %</B>
				5263
				5264	<DD>
				5265	multiplication, division, remainder
				5266	<DT><B>+ -</B>
				5267
				5268	<DD>
				5269	addition, subtraction
				5270	<DT><B><< >></B>
				5271
				5272	<DD>
				5273	left and right bitwise shifts
				5274	<DT><B><= >= < ></B>
				5275
				5276	<DD>
				5277	comparison
				5278	<DT><B>== !=</B>
				5279
				5280	<DD>
				5281	equality and inequality
				5282	<DT><B>&</B>
				5283
				5284	<DD>
				5285	bitwise AND
				5286	<DT><B>^</B>
				5287
				5288	<DD>
				5289	bitwise exclusive OR
				5290	<DT><B>\|</B>
				5291
				5292	<DD>
				5293	bitwise OR
				5294	<DT><B>&&</B>
				5295
				5296	<DD>
				5297	logical AND
				5298	<DT><B>\|\|</B>
				5299
				5300	<DD>
				5301	logical OR
				5302	<DT><B></B><I>expr</I>?<I>expr</I>:<I>expr</I>
				5303
				5304	<DD>
				5305	conditional operator
				5306	<DT><B>= *= /= %= += -= <<= >>= &= ^= \|=</B>
				5307
				5308	<DD>
				5309	assignment
				5310	<DT><B></B><I>expr1</I> , <I>expr2</I>
				5311
				5312	<DD>
				5313	comma
				5314
				5315	</DL>
				5316	<P>
				5317
				5318	Shell variables are allowed as operands; parameter expansion is
				5319	performed before the expression is evaluated.
				5320	Within an expression, shell variables may also be referenced by name
				5321	without using the parameter expansion syntax.
				5322	A shell variable that is null or unset evaluates to 0 when referenced
				5323	by name without using the parameter expansion syntax.
				5324	The value of a variable is evaluated as an arithmetic expression
				5325	when it is referenced, or when a variable which has been given the
				5326	<I>integer</I> attribute using <B>declare -i</B> is assigned a value.
				5327	A null value evaluates to 0.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5328	A shell variable need not have its <I>integer</I> attribute
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5329	turned on to be used in an expression.
				5330	<P>
				5331
				5332	Constants with a leading 0 are interpreted as octal numbers.
				5333	A leading 0x or 0X denotes hexadecimal.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5334	Otherwise, numbers take the form [<I>base#</I>]n, where the optional <I>base</I>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5335	is a decimal number between 2 and 64 representing the arithmetic
				5336	base, and <I>n</I> is a number in that base.
				5337	If <I>base#</I> is omitted, then base 10 is used.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	5338	When specifying <I>n</I>,
				5339	the digits greater< than 9 are represented by the lowercase letters,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5340	the uppercase letters, @, and _, in that order.
				5341	If <I>base</I> is less than or equal to 36, lowercase and uppercase
				5342	letters may be used interchangeably to represent numbers between 10
				5343	and 35.
				5344	<P>
				5345
				5346	Operators are evaluated in order of precedence. Sub-expressions in
				5347	parentheses are evaluated first and may override the precedence
				5348	rules above.
				5349	<A NAME="lbBW"> </A>
				5350	<H3>CONDITIONAL EXPRESSIONS</H3>
				5351
				5352	Conditional expressions are used by the <B>[[</B> compound command and
				5353	the <B>test</B> and <B>[</B> builtin commands to test file attributes
				5354	and perform string and arithmetic comparisons.
				5355	Expressions are formed from the following unary or binary primaries.
				5356	If any <I>file</I> argument to one of the primaries is of the form
				5357	<I>/dev/fd/n</I>, then file descriptor <I>n</I> is checked.
				5358	If the <I>file</I> argument to one of the primaries is one of
				5359	<I>/dev/stdin</I>, <I>/dev/stdout</I>, or <I>/dev/stderr</I>, file
				5360	descriptor 0, 1, or 2, respectively, is checked.
				5361	<P>
				5362
				5363	Unless otherwise specified, primaries that operate on files follow symbolic
				5364	links and operate on the target of the link, rather than the link itself.
				5365	<P>
				5366
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5367
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5368	When used with <B>[[</B>, the <B><</B> and <B>></B> operators sort
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5369	lexicographically using the current locale.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5370	The <B>test</B> command sorts using ASCII ordering.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5371	<P>
				5372
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5373	<DL COMPACT>
				5374	<DT><B>-a </B><I>file</I>
				5375
				5376	<DD>
				5377	True if <I>file</I> exists.
				5378	<DT><B>-b </B><I>file</I>
				5379
				5380	<DD>
				5381	True if <I>file</I> exists and is a block special file.
				5382	<DT><B>-c </B><I>file</I>
				5383
				5384	<DD>
				5385	True if <I>file</I> exists and is a character special file.
				5386	<DT><B>-d </B><I>file</I>
				5387
				5388	<DD>
				5389	True if <I>file</I> exists and is a directory.
				5390	<DT><B>-e </B><I>file</I>
				5391
				5392	<DD>
				5393	True if <I>file</I> exists.
				5394	<DT><B>-f </B><I>file</I>
				5395
				5396	<DD>
				5397	True if <I>file</I> exists and is a regular file.
				5398	<DT><B>-g </B><I>file</I>
				5399
				5400	<DD>
				5401	True if <I>file</I> exists and is set-group-id.
				5402	<DT><B>-h </B><I>file</I>
				5403
				5404	<DD>
				5405	True if <I>file</I> exists and is a symbolic link.
				5406	<DT><B>-k </B><I>file</I>
				5407
				5408	<DD>
				5409	True if <I>file</I> exists and its ``sticky'' bit is set.
				5410	<DT><B>-p </B><I>file</I>
				5411
				5412	<DD>
				5413	True if <I>file</I> exists and is a named pipe (FIFO).
				5414	<DT><B>-r </B><I>file</I>
				5415
				5416	<DD>
				5417	True if <I>file</I> exists and is readable.
				5418	<DT><B>-s </B><I>file</I>
				5419
				5420	<DD>
				5421	True if <I>file</I> exists and has a size greater than zero.
				5422	<DT><B>-t </B><I>fd</I>
				5423
				5424	<DD>
				5425	True if file descriptor
				5426	<I>fd</I>
				5427
				5428	is open and refers to a terminal.
				5429	<DT><B>-u </B><I>file</I>
				5430
				5431	<DD>
				5432	True if <I>file</I> exists and its set-user-id bit is set.
				5433	<DT><B>-w </B><I>file</I>
				5434
				5435	<DD>
				5436	True if <I>file</I> exists and is writable.
				5437	<DT><B>-x </B><I>file</I>
				5438
				5439	<DD>
				5440	True if <I>file</I> exists and is executable.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5441	<DT><B>-G </B><I>file</I>
				5442
				5443	<DD>
				5444	True if <I>file</I> exists and is owned by the effective group id.
				5445	<DT><B>-L </B><I>file</I>
				5446
				5447	<DD>
				5448	True if <I>file</I> exists and is a symbolic link.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5449	<DT><B>-N </B><I>file</I>
				5450
				5451	<DD>
				5452	True if <I>file</I> exists and has been modified since it was last read.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5453	<DT><B>-O </B><I>file</I>
				5454
				5455	<DD>
				5456	True if <I>file</I> exists and is owned by the effective user id.
				5457	<DT><B>-S </B><I>file</I>
				5458
				5459	<DD>
				5460	True if <I>file</I> exists and is a socket.
				5461	<DT><I>file1</I> <B>-ef</B> <I>file2</I><DD>
				5462	True if <I>file1</I> and <I>file2</I> refer to the same device and
				5463	inode numbers.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5464	<DT><I>file1</I> -<B>nt</B> <I>file2</I><DD>
				5465	True if <I>file1</I> is newer (according to modification date) than <I>file2</I>,
				5466	or if <I>file1</I> exists and file2 does not.
				5467	<DT><I>file1</I> -<B>ot</B> <I>file2</I><DD>
				5468	True if <I>file1</I> is older than <I>file2</I>, or if <I>file2</I> exists
				5469	and <I>file1</I> does not.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5470	<DT><B>-o </B><I>optname</I>
				5471
				5472	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5473	True if the shell option
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5474	<I>optname</I>
				5475
				5476	is enabled.
				5477	See the list of options under the description of the
				5478	<B>-o</B>
				5479
				5480	option to the
				5481	<B>set</B>
				5482
				5483	builtin below.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5484	<DT><B>-v </B><I>varname</I>
				5485
				5486	<DD>
				5487	True if the shell variable
				5488	<I>varname</I>
				5489
				5490	is set (has been assigned a value).
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	5491	<DT><B>-R </B><I>varname</I>
				5492
				5493	<DD>
				5494	True if the shell variable
				5495	<I>varname</I>
				5496
				5497	is set and is a name reference.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5498	<DT><B>-z </B><I>string</I>
				5499
				5500	<DD>
				5501	True if the length of <I>string</I> is zero.
				5502	<DT><I>string</I><DD>
				5503
				5504	<DT><B>-n </B><I>string</I>
				5505
				5506	<DD>
				5507
				5508	True if the length of
				5509	<I>string</I>
				5510
				5511	is non-zero.
				5512	<DT><I>string1</I> <B>==</B> <I>string2</I><DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5513
				5514	<DT><I>string1</I> <B>=</B> <I>string2</I><DD>
				5515
				5516	True if the strings are equal. <B>=</B> should be used
				5517	with the <B>test</B> command for POSIX conformance.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	5518	When used with the <B>[[</B> command, this performs pattern matching as
				5519	described above (<B>Compound Commands</B>).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5520	<DT><I>string1</I> <B>!=</B> <I>string2</I><DD>
				5521	True if the strings are not equal.
				5522	<DT><I>string1</I> <B><</B> <I>string2</I><DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5523	True if <I>string1</I> sorts before <I>string2</I> lexicographically.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5524	<DT><I>string1</I> <B>></B> <I>string2</I><DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5525	True if <I>string1</I> sorts after <I>string2</I> lexicographically.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5526	<DT><I>arg1</I> <B>OP</B> <I>arg2</I>
				5527
				5528	<DD>
				5529	<FONT SIZE=-1><B>OP</B>
				5530
				5531	</FONT>
				5532	is one of
				5533	<B>-eq</B>,
				5534
				5535	<B>-ne</B>,
				5536
				5537	<B>-lt</B>,
				5538
				5539	<B>-le</B>,
				5540
				5541	<B>-gt</B>,
				5542
				5543	or
				5544	<B>-ge</B>.
				5545
				5546	These arithmetic binary operators return true if <I>arg1</I>
				5547	is equal to, not equal to, less than, less than or equal to,
				5548	greater than, or greater than or equal to <I>arg2</I>, respectively.
				5549	<I>Arg1</I>
				5550
				5551	and
				5552	<I>arg2</I>
				5553
				5554	may be positive or negative integers.
				5555
				5556	</DL>
				5557	<A NAME="lbBX"> </A>
				5558	<H3>SIMPLE COMMAND EXPANSION</H3>
				5559
				5560	When a simple command is executed, the shell performs the following
				5561	expansions, assignments, and redirections, from left to right.
				5562	<DL COMPACT>
				5563	<DT>1.<DD>
				5564	The words that the parser has marked as variable assignments (those
				5565	preceding the command name) and redirections are saved for later
				5566	processing.
				5567	<DT>2.<DD>
				5568	The words that are not variable assignments or redirections are
				5569	expanded. If any words remain after expansion, the first word
				5570	is taken to be the name of the command and the remaining words are
				5571	the arguments.
				5572	<DT>3.<DD>
				5573	Redirections are performed as described above under
				5574	<FONT SIZE=-1><B>REDIRECTION</B>.
				5575
				5576	</FONT>
				5577	<DT>4.<DD>
				5578	The text after the <B>=</B> in each variable assignment undergoes tilde
				5579	expansion, parameter expansion, command substitution, arithmetic expansion,
				5580	and quote removal before being assigned to the variable.
				5581	</DL>
				5582	<P>
				5583
				5584	If no command name results, the variable assignments affect the current
				5585	shell environment. Otherwise, the variables are added to the environment
				5586	of the executed command and do not affect the current shell environment.
				5587	If any of the assignments attempts to assign a value to a readonly variable,
				5588	an error occurs, and the command exits with a non-zero status.
				5589	<P>
				5590
				5591	If no command name results, redirections are performed, but do not
				5592	affect the current shell environment. A redirection error causes the
				5593	command to exit with a non-zero status.
				5594	<P>
				5595
				5596	If there is a command name left after expansion, execution proceeds as
				5597	described below. Otherwise, the command exits. If one of the expansions
				5598	contained a command substitution, the exit status of the command is
				5599	the exit status of the last command substitution performed. If there
				5600	were no command substitutions, the command exits with a status of zero.
				5601	<A NAME="lbBY"> </A>
				5602	<H3>COMMAND EXECUTION</H3>
				5603
				5604	After a command has been split into words, if it results in a
				5605	simple command and an optional list of arguments, the following
				5606	actions are taken.
				5607	<P>
				5608
				5609	If the command name contains no slashes, the shell attempts to
				5610	locate it. If there exists a shell function by that name, that
				5611	function is invoked as described above in
				5612	<FONT SIZE=-1><B>FUNCTIONS</B>.
				5613
				5614	</FONT>
				5615	If the name does not match a function, the shell searches for
				5616	it in the list of shell builtins. If a match is found, that
				5617	builtin is invoked.
				5618	<P>
				5619
				5620	If the name is neither a shell function nor a builtin,
				5621	and contains no slashes,
				5622	<B>bash</B>
				5623
				5624	searches each element of the
				5625	<FONT SIZE=-1><B>PATH</B>
				5626
				5627	</FONT>
				5628	for a directory containing an executable file by that name.
				5629	<B>Bash</B>
				5630
				5631	uses a hash table to remember the full pathnames of executable
				5632	files (see
				5633	<B>hash</B>
				5634
				5635	under
				5636	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				5637
				5638	</FONT>
				5639	below).
				5640	A full search of the directories in
				5641	<FONT SIZE=-1><B>PATH</B>
				5642
				5643	</FONT>
				5644	is performed only if the command is not found in the hash table.
				5645	If the search is unsuccessful, the shell searches for a defined shell
				5646	function named <B>command_not_found_handle</B>.
				5647	If that function exists, it is invoked with the original command and
				5648	the original command's arguments as its arguments, and the function's
				5649	exit status becomes the exit status of the shell.
				5650	If that function is not defined, the shell prints an error
				5651	message and returns an exit status of 127.
				5652	<P>
				5653
				5654	If the search is successful, or if the command name contains
				5655	one or more slashes, the shell executes the named program in a
				5656	separate execution environment.
				5657	Argument 0 is set to the name given, and the remaining arguments
				5658	to the command are set to the arguments given, if any.
				5659	<P>
				5660
				5661	If this execution fails because the file is not in executable
				5662	format, and the file is not a directory, it is assumed to be
				5663	a <I>shell script</I>, a file
				5664	containing shell commands. A subshell is spawned to execute
				5665	it. This subshell reinitializes itself, so
				5666	that the effect is as if a new shell had been invoked
				5667	to handle the script, with the exception that the locations of
				5668	commands remembered by the parent (see
				5669	<B>hash</B>
				5670
				5671	below under
				5672	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>)</FONT>
				5673	are retained by the child.
				5674	<P>
				5675
				5676	If the program is a file beginning with
				5677	<B>#!</B>,
				5678
				5679	the remainder of the first line specifies an interpreter
				5680	for the program. The shell executes the
				5681	specified interpreter on operating systems that do not
				5682	handle this executable format themselves. The arguments to the
				5683	interpreter consist of a single optional argument following the
				5684	interpreter name on the first line of the program, followed
				5685	by the name of the program, followed by the command
				5686	arguments, if any.
				5687	<A NAME="lbBZ"> </A>
				5688	<H3>COMMAND EXECUTION ENVIRONMENT</H3>
				5689
				5690	The shell has an <I>execution environment</I>, which consists of the
				5691	following:
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5692	<DL COMPACT>
				5693	<DT>*<DD>
				5694	open files inherited by the shell at invocation, as modified by
				5695	redirections supplied to the <B>exec</B> builtin
				5696	<DT>*<DD>
				5697	the current working directory as set by <B>cd</B>, <B>pushd</B>, or
				5698	<B>popd</B>, or inherited by the shell at invocation
				5699	<DT>*<DD>
				5700	the file creation mode mask as set by <B>umask</B> or inherited from
				5701	the shell's parent
				5702	<DT>*<DD>
				5703	current traps set by <B>trap</B>
				5704	<DT>*<DD>
				5705	shell parameters that are set by variable assignment or with <B>set</B>
				5706	or inherited from the shell's parent in the environment
				5707	<DT>*<DD>
				5708	shell functions defined during execution or inherited from the shell's
				5709	parent in the environment
				5710	<DT>*<DD>
				5711	options enabled at invocation (either by default or with command-line
				5712	arguments) or by <B>set</B>
				5713	<DT>*<DD>
				5714	options enabled by <B>shopt</B>
				5715	<DT>*<DD>
				5716	shell aliases defined with <B>alias</B>
				5717	<DT>*<DD>
				5718	various process IDs, including those of background jobs, the value
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5719	of <B>$$</B>, and the value of
				5720	<FONT SIZE=-1><B>PPID</B>
				5721
				5722	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5723	</DL>
				5724	<P>
				5725
				5726	When a simple command other than a builtin or shell function
				5727	is to be executed, it
				5728	is invoked in a separate execution environment that consists of
				5729	the following. Unless otherwise noted, the values are inherited
				5730	from the shell.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	5731
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5732	<DL COMPACT>
				5733	<DT>*<DD>
				5734	the shell's open files, plus any modifications and additions specified
				5735	by redirections to the command
				5736	<DT>*<DD>
				5737	the current working directory
				5738	<DT>*<DD>
				5739	the file creation mode mask
				5740	<DT>*<DD>
				5741	shell variables and functions marked for export, along with variables
				5742	exported for the command, passed in the environment
				5743	<DT>*<DD>
				5744	traps caught by the shell are reset to the values inherited from the
				5745	shell's parent, and traps ignored by the shell are ignored
				5746	</DL>
				5747	<P>
				5748
				5749	A command invoked in this separate environment cannot affect the
				5750	shell's execution environment.
				5751	<P>
				5752
				5753	Command substitution, commands grouped with parentheses,
				5754	and asynchronous commands are invoked in a
				5755	subshell environment that is a duplicate of the shell environment,
				5756	except that traps caught by the shell are reset to the values
				5757	that the shell inherited from its parent at invocation. Builtin
				5758	commands that are invoked as part of a pipeline are also executed in a
				5759	subshell environment. Changes made to the subshell environment
				5760	cannot affect the shell's execution environment.
				5761	<P>
				5762
				5763	Subshells spawned to execute command substitutions inherit the value of
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	5764	the <B>-e</B> option from the parent shell. When not in <I>posix</I> mode,
				5765	<B>bash</B> clears the <B>-e</B> option in such subshells.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5766	<P>
				5767
				5768	If a command is followed by a <B>&</B> and job control is not active, the
				5769	default standard input for the command is the empty file <I>/dev/null</I>.
				5770	Otherwise, the invoked command inherits the file descriptors of the calling
				5771	shell as modified by redirections.
				5772	<A NAME="lbCA"> </A>
				5773	<H3>ENVIRONMENT</H3>
				5774
				5775	When a program is invoked it is given an array of strings
				5776	called the
				5777	<I>environment</I>.
				5778
				5779	This is a list of
				5780	<I>name</I>-<I>value</I> pairs, of the form
				5781	<I>name</I>=value.
				5782
				5783	<P>
				5784
				5785	The shell provides several ways to manipulate the environment.
				5786	On invocation, the shell scans its own environment and
				5787	creates a parameter for each name found, automatically marking
				5788	it for
				5789	<I>export</I>
				5790
				5791	to child processes. Executed commands inherit the environment.
				5792	The
				5793	<B>export</B>
				5794
				5795	and
				5796	<B>declare -x</B>
				5797
				5798	commands allow parameters and functions to be added to and
				5799	deleted from the environment. If the value of a parameter
				5800	in the environment is modified, the new value becomes part
				5801	of the environment, replacing the old. The environment
				5802	inherited by any executed command consists of the shell's
				5803	initial environment, whose values may be modified in the shell,
				5804	less any pairs removed by the
				5805	<B>unset</B>
				5806
				5807	command, plus any additions via the
				5808	<B>export</B>
				5809
				5810	and
				5811	<B>declare -x</B>
				5812
				5813	commands.
				5814	<P>
				5815
				5816	The environment for any
				5817	<I>simple command</I>
				5818
				5819	or function may be augmented temporarily by prefixing it with
				5820	parameter assignments, as described above in
				5821	<FONT SIZE=-1><B>PARAMETERS</B>.
				5822
				5823	</FONT>
				5824	These assignment statements affect only the environment seen
				5825	by that command.
				5826	<P>
				5827
				5828	If the
				5829	<B>-k</B>
				5830
				5831	option is set (see the
				5832	<B>set</B>
				5833
				5834	builtin command below), then
				5835	<I>all</I>
				5836
				5837	parameter assignments are placed in the environment for a command,
				5838	not just those that precede the command name.
				5839	<P>
				5840
				5841	When
				5842	<B>bash</B>
				5843
				5844	invokes an external command, the variable
				5845	<B>_</B>
				5846
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	5847	is set to the full filename of the command and passed to that
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	5848	command in its environment.
				5849	<A NAME="lbCB"> </A>
				5850	<H3>EXIT STATUS</H3>
				5851
				5852	<P>
				5853
				5854	The exit status of an executed command is the value returned by the
				5855	<I>waitpid</I> system call or equivalent function. Exit statuses
				5856	fall between 0 and 255, though, as explained below, the shell may
				5857	use values above 125 specially. Exit statuses from shell builtins and
				5858	compound commands are also limited to this range. Under certain
				5859	circumstances, the shell will use special values to indicate specific
				5860	failure modes.
				5861	<P>
				5862
				5863	For the shell's purposes, a command which exits with a
				5864	zero exit status has succeeded. An exit status of zero
				5865	indicates success. A non-zero exit status indicates failure.
				5866	When a command terminates on a fatal signal <I>N</I>, <B>bash</B> uses
				5867	the value of 128+<I>N</I> as the exit status.
				5868	<P>
				5869
				5870	If a command is not found, the child process created to
				5871	execute it returns a status of 127. If a command is found
				5872	but is not executable, the return status is 126.
				5873	<P>
				5874
				5875	If a command fails because of an error during expansion or redirection,
				5876	the exit status is greater than zero.
				5877	<P>
				5878
				5879	Shell builtin commands return a status of 0 (<I>true</I>) if
				5880	successful, and non-zero (<I>false</I>) if an error occurs
				5881	while they execute.
				5882	All builtins return an exit status of 2 to indicate incorrect usage.
				5883	<P>
				5884
				5885	<B>Bash</B> itself returns the exit status of the last command
				5886	executed, unless a syntax error occurs, in which case it exits
				5887	with a non-zero value. See also the <B>exit</B> builtin
				5888	command below.
				5889	<A NAME="lbCC"> </A>
				5890	<H3>SIGNALS</H3>
				5891
				5892	When <B>bash</B> is interactive, in the absence of any traps, it ignores
				5893	<FONT SIZE=-1><B>SIGTERM</B>
				5894
				5895	</FONT>
				5896	(so that <B>kill 0</B> does not kill an interactive shell),
				5897	and
				5898	<FONT SIZE=-1><B>SIGINT</B>
				5899
				5900	</FONT>
				5901	is caught and handled (so that the <B>wait</B> builtin is interruptible).
				5902	In all cases, <B>bash</B> ignores
				5903	<FONT SIZE=-1><B>SIGQUIT</B>.
				5904
				5905	</FONT>
				5906	If job control is in effect,
				5907	<B>bash</B>
				5908
				5909	ignores
				5910	<FONT SIZE=-1><B>SIGTTIN</B>,
				5911
				5912	</FONT>
				5913	<FONT SIZE=-1><B>SIGTTOU</B>,
				5914
				5915	</FONT>
				5916	and
				5917	<FONT SIZE=-1><B>SIGTSTP</B>.
				5918
				5919	</FONT>
				5920	<P>
				5921
				5922	Non-builtin commands run by <B>bash</B> have signal handlers
				5923	set to the values inherited by the shell from its parent.
				5924	When job control is not in effect, asynchronous commands
				5925	ignore
				5926	<FONT SIZE=-1><B>SIGINT</B>
				5927
				5928	</FONT>
				5929	and
				5930	<FONT SIZE=-1><B>SIGQUIT</B>
				5931
				5932	</FONT>
				5933	in addition to these inherited handlers.
				5934	Commands run as a result of command substitution ignore the
				5935	keyboard-generated job control signals
				5936	<FONT SIZE=-1><B>SIGTTIN</B>,
				5937
				5938	</FONT>
				5939	<FONT SIZE=-1><B>SIGTTOU</B>,
				5940
				5941	</FONT>
				5942	and
				5943	<FONT SIZE=-1><B>SIGTSTP</B>.
				5944
				5945	</FONT>
				5946	<P>
				5947
				5948	The shell exits by default upon receipt of a
				5949	<FONT SIZE=-1><B>SIGHUP</B>.
				5950
				5951	</FONT>
				5952	Before exiting, an interactive shell resends the
				5953	<FONT SIZE=-1><B>SIGHUP</B>
				5954
				5955	</FONT>
				5956	to all jobs, running or stopped.
				5957	Stopped jobs are sent
				5958	<FONT SIZE=-1><B>SIGCONT</B>
				5959
				5960	</FONT>
				5961	to ensure that they receive the
				5962	<FONT SIZE=-1><B>SIGHUP</B>.
				5963
				5964	</FONT>
				5965	To prevent the shell from
				5966	sending the signal to a particular job, it should be removed from the
				5967	jobs table with the
				5968	<B>disown</B>
				5969
				5970	builtin (see
				5971	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				5972
				5973	</FONT>
				5974	below) or marked
				5975	to not receive
				5976	<FONT SIZE=-1><B>SIGHUP</B>
				5977
				5978	</FONT>
				5979	using
				5980	<B>disown -h</B>.
				5981
				5982	<P>
				5983
				5984	If the
				5985	<B>huponexit</B>
				5986
				5987	shell option has been set with
				5988	<B>shopt</B>,
				5989
				5990	<B>bash</B>
				5991
				5992	sends a
				5993	<FONT SIZE=-1><B>SIGHUP</B>
				5994
				5995	</FONT>
				5996	to all jobs when an interactive login shell exits.
				5997	<P>
				5998
				5999	If <B>bash</B> is waiting for a command to complete and receives a signal
				6000	for which a trap has been set, the trap will not be executed until
				6001	the command completes.
				6002	When <B>bash</B> is waiting for an asynchronous command via the <B>wait</B>
				6003	builtin, the reception of a signal for which a trap has been set will
				6004	cause the <B>wait</B> builtin to return immediately with an exit status
				6005	greater than 128, immediately after which the trap is executed.
				6006	<A NAME="lbCD"> </A>
				6007	<H3>JOB CONTROL</H3>
				6008
				6009	<I>Job control</I>
				6010
				6011	refers to the ability to selectively stop (<I>suspend</I>)
				6012	the execution of processes and continue (<I>resume</I>)
				6013	their execution at a later point. A user typically employs
				6014	this facility via an interactive interface supplied jointly
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	6015	by the operating system kernel's terminal driver and
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6016	<B>bash</B>.
				6017
				6018	<P>
				6019
				6020	The shell associates a
				6021	<I>job</I>
				6022
				6023	with each pipeline. It keeps a table of currently executing
				6024	jobs, which may be listed with the
				6025	<B>jobs</B>
				6026
				6027	command. When
				6028	<B>bash</B>
				6029
				6030	starts a job asynchronously (in the
				6031	<I>background</I>),
				6032
				6033	it prints a line that looks like:
				6034	<DL COMPACT><DT><DD>
				6035	<P>
				6036
				6037	[1] 25647
				6038	</DL>
				6039
				6040	<P>
				6041
				6042	indicating that this job is job number 1 and that the process ID
				6043	of the last process in the pipeline associated with this job is 25647.
				6044	All of the processes in a single pipeline are members of the same job.
				6045	<B>Bash</B>
				6046
				6047	uses the
				6048	<I>job</I>
				6049
				6050	abstraction as the basis for job control.
				6051	<P>
				6052
				6053	To facilitate the implementation of the user interface to job
				6054	control, the operating system maintains the notion of a <I>current terminal
				6055	process group ID</I>. Members of this process group (processes whose
				6056	process group ID is equal to the current terminal process group ID)
				6057	receive keyboard-generated signals such as
				6058	<FONT SIZE=-1><B>SIGINT</B>.
				6059
				6060	</FONT>
				6061	These processes are said to be in the
				6062	<I>foreground</I>.
				6063
				6064	<I>Background</I>
				6065
				6066	processes are those whose process group ID differs from the terminal's;
				6067	such processes are immune to keyboard-generated signals.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	6068	Only foreground processes are allowed to read from or, if the
				6069	user so specifies with <TT>stty tostop</TT>, write to the
				6070	terminal.
				6071	Background processes which attempt to read from (write to when
				6072	<TT>stty tostop</TT> is in effect) the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6073	terminal are sent a
				6074	<FONT SIZE=-1><B>SIGTTIN (SIGTTOU)</B>
				6075
				6076	</FONT>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	6077	signal by the kernel's terminal driver,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6078	which, unless caught, suspends the process.
				6079	<P>
				6080
				6081	If the operating system on which
				6082	<B>bash</B>
				6083
				6084	is running supports
				6085	job control,
				6086	<B>bash</B>
				6087
				6088	contains facilities to use it.
				6089	Typing the
				6090	<I>suspend</I>
				6091
				6092	character (typically
				6093	<B>^Z</B>,
				6094
				6095	Control-Z) while a process is running
				6096	causes that process to be stopped and returns control to
				6097	<B>bash</B>.
				6098
				6099	Typing the
				6100	<I>delayed suspend</I>
				6101
				6102	character (typically
				6103	<B>^Y</B>,
				6104
				6105	Control-Y) causes the process to be stopped when it
				6106	attempts to read input from the terminal, and control to
				6107	be returned to
				6108	<B>bash</B>.
				6109
				6110	The user may then manipulate the state of this job, using the
				6111	<B>bg</B>
				6112
				6113	command to continue it in the background, the
				6114	<B>fg</B>
				6115
				6116	command to continue it in the foreground, or
				6117	the
				6118	<B>kill</B>
				6119
				6120	command to kill it. A <B>^Z</B> takes effect immediately,
				6121	and has the additional side effect of causing pending output
				6122	and typeahead to be discarded.
				6123	<P>
				6124
				6125	There are a number of ways to refer to a job in the shell.
				6126	The character
				6127	<B>%</B>
				6128
				6129	introduces a job specification (<I>jobspec</I>). Job number
				6130	<I>n</I>
				6131
				6132	may be referred to as
				6133	<B>%n</B>.
				6134
				6135	A job may also be referred to using a prefix of the name used to
				6136	start it, or using a substring that appears in its command line.
				6137	For example,
				6138	<B>%ce</B>
				6139
				6140	refers to a stopped
				6141	<B>ce</B>
				6142
				6143	job. If a prefix matches more than one job,
				6144	<B>bash</B>
				6145
				6146	reports an error. Using
				6147	<B>%?ce</B>,
				6148
				6149	on the other hand, refers to any job containing the string
				6150	<B>ce</B>
				6151
				6152	in its command line. If the substring matches more than one job,
				6153	<B>bash</B>
				6154
				6155	reports an error. The symbols
				6156	<B>%%</B>
				6157
				6158	and
				6159	<B>%+</B>
				6160
				6161	refer to the shell's notion of the
				6162	<I>current job</I>,
				6163
				6164	which is the last job stopped while it was in
				6165	the foreground or started in the background.
				6166	The
				6167	<I>previous job</I>
				6168
				6169	may be referenced using
				6170	<B>%-</B>.
				6171
				6172	If there is only a single job, <B>%+</B> and <B>%-</B> can both be used
				6173	to refer to that job.
				6174	In output pertaining to jobs (e.g., the output of the
				6175	<B>jobs</B>
				6176
				6177	command), the current job is always flagged with a
				6178	<B>+</B>,
				6179
				6180	and the previous job with a
				6181	<B>-</B>.
				6182
				6183	A single % (with no accompanying job specification) also refers to the
				6184	current job.
				6185	<P>
				6186
				6187	Simply naming a job can be used to bring it into the
				6188	foreground:
				6189	<B>%1</B>
				6190
				6191	is a synonym for
				6192	<B>``fg %1''</B>,
				6193	bringing job 1 from the background into the foreground.
				6194	Similarly,
				6195	<B>``%1 &''</B>
				6196
				6197	resumes job 1 in the background, equivalent to
				6198	<B>``bg %1''</B>.
				6199	<P>
				6200
				6201	The shell learns immediately whenever a job changes state.
				6202	Normally,
				6203	<B>bash</B>
				6204
				6205	waits until it is about to print a prompt before reporting
				6206	changes in a job's status so as to not interrupt
				6207	any other output. If the
				6208	<B>-b</B>
				6209
				6210	option to the
				6211	<B>set</B>
				6212
				6213	builtin command
				6214	is enabled,
				6215	<B>bash</B>
				6216
				6217	reports such changes immediately.
				6218	Any trap on
				6219	<FONT SIZE=-1><B>SIGCHLD</B>
				6220
				6221	</FONT>
				6222	is executed for each child that exits.
				6223	<P>
				6224
				6225	If an attempt to exit
				6226	<B>bash</B>
				6227
				6228	is made while jobs are stopped (or, if the <B>checkjobs</B> shell option has
				6229	been enabled using the <B>shopt</B> builtin, running), the shell prints a
				6230	warning message, and, if the <B>checkjobs</B> option is enabled, lists the
				6231	jobs and their statuses.
				6232	The
				6233	<B>jobs</B>
				6234
				6235	command may then be used to inspect their status.
				6236	If a second attempt to exit is made without an intervening command,
				6237	the shell does not print another warning, and any stopped
				6238	jobs are terminated.
				6239	<A NAME="lbCE"> </A>
				6240	<H3>PROMPTING</H3>
				6241
				6242	When executing interactively,
				6243	<B>bash</B>
				6244
				6245	displays the primary prompt
				6246	<FONT SIZE=-1><B>PS1</B>
				6247
				6248	</FONT>
				6249	when it is ready to read a command, and the secondary prompt
				6250	<FONT SIZE=-1><B>PS2</B>
				6251
				6252	</FONT>
				6253	when it needs more input to complete a command.
				6254	<B>Bash</B>
				6255
				6256	allows these prompt strings to be customized by inserting a number of
				6257	backslash-escaped special characters that are decoded as follows:
				6258	<DL COMPACT><DT><DD>
				6259
				6260	<DL COMPACT>
				6261	<DT><B>\a</B>
				6262
				6263	<DD>
				6264	an ASCII bell character (07)
				6265	<DT><B>\d</B>
				6266
				6267	<DD>
				6268	the date in "Weekday Month Date" format (e.g., "Tue May 26")
				6269	<DT><B>\D{</B><I>format</I>}
				6270
				6271	<DD>
				6272	the <I>format</I> is passed to <I>strftime</I>(3) and the result is inserted
				6273	into the prompt string; an empty <I>format</I> results in a locale-specific
				6274	time representation. The braces are required
				6275	<DT><B>\e</B>
				6276
				6277	<DD>
				6278	an ASCII escape character (033)
				6279	<DT><B>\h</B>
				6280
				6281	<DD>
				6282	the hostname up to the first `.'
				6283	<DT><B>\H</B>
				6284
				6285	<DD>
				6286	the hostname
				6287	<DT><B>\j</B>
				6288
				6289	<DD>
				6290	the number of jobs currently managed by the shell
				6291	<DT><B>\l</B>
				6292
				6293	<DD>
				6294	the basename of the shell's terminal device name
				6295	<DT><B>\n</B>
				6296
				6297	<DD>
				6298	newline
				6299	<DT><B>\r</B>
				6300
				6301	<DD>
				6302	carriage return
				6303	<DT><B>\s</B>
				6304
				6305	<DD>
				6306	the name of the shell, the basename of
				6307	<B>$0</B>
				6308
				6309	(the portion following the final slash)
				6310	<DT><B>\t</B>
				6311
				6312	<DD>
				6313	the current time in 24-hour HH:MM:SS format
				6314	<DT><B>\T</B>
				6315
				6316	<DD>
				6317	the current time in 12-hour HH:MM:SS format
				6318	<DT><B>\@</B>
				6319
				6320	<DD>
				6321	the current time in 12-hour am/pm format
				6322	<DT><B>\A</B>
				6323
				6324	<DD>
				6325	the current time in 24-hour HH:MM format
				6326	<DT><B>\u</B>
				6327
				6328	<DD>
				6329	the username of the current user
				6330	<DT><B>\v</B>
				6331
				6332	<DD>
				6333	the version of <B>bash</B> (e.g., 2.00)
				6334	<DT><B>\V</B>
				6335
				6336	<DD>
				6337	the release of <B>bash</B>, version + patch level (e.g., 2.00.0)
				6338	<DT><B>\w</B>
				6339
				6340	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	6341	the current working directory, with
				6342	<FONT SIZE=-1><B>$HOME</B>
				6343
				6344	</FONT>
				6345	abbreviated with a tilde
				6346	(uses the value of the
				6347	<FONT SIZE=-1><B>PROMPT_DIRTRIM</B>
				6348
				6349	</FONT>
				6350	variable)
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6351	<DT><B>\W</B>
				6352
				6353	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	6354	the basename of the current working directory, with
				6355	<FONT SIZE=-1><B>$HOME</B>
				6356
				6357	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6358	abbreviated with a tilde
				6359	<DT><B>\!</B>
				6360
				6361	<DD>
				6362	the history number of this command
				6363	<DT><B>\#</B>
				6364
				6365	<DD>
				6366	the command number of this command
				6367	<DT><B>\$</B>
				6368
				6369	<DD>
				6370	if the effective UID is 0, a
				6371	<B>#</B>,
				6372
				6373	otherwise a
				6374	<B>$</B>
				6375
				6376	<DT><B>\</B><I>nnn</I>
				6377
				6378	<DD>
				6379	the character corresponding to the octal number <I>nnn</I>
				6380	<DT><B>\\</B>
				6381
				6382	<DD>
				6383	a backslash
				6384	<DT><B>\[</B>
				6385
				6386	<DD>
				6387	begin a sequence of non-printing characters, which could be used to
				6388	embed a terminal control sequence into the prompt
				6389	<DT><B>\]</B>
				6390
				6391	<DD>
				6392	end a sequence of non-printing characters
				6393
				6394	</DL></DL>
				6395
				6396	<P>
				6397
				6398	The command number and the history number are usually different:
				6399	the history number of a command is its position in the history
				6400	list, which may include commands restored from the history file
				6401	(see
				6402	<FONT SIZE=-1><B>HISTORY</B>
				6403
				6404	</FONT>
				6405	below), while the command number is the position in the sequence
				6406	of commands executed during the current shell session.
				6407	After the string is decoded, it is expanded via
				6408	parameter expansion, command substitution, arithmetic
				6409	expansion, and quote removal, subject to the value of the
				6410	<B>promptvars</B>
				6411
				6412	shell option (see the description of the
				6413	<B>shopt</B>
				6414
				6415	command under
				6416	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				6417
				6418	</FONT>
				6419	below).
				6420	<A NAME="lbCF"> </A>
				6421	<H3>READLINE</H3>
				6422
				6423	This is the library that handles reading input when using an interactive
				6424	shell, unless the
				6425	<B>--noediting</B>
				6426
				6427	option is given at shell invocation.
				6428	Line editing is also used when using the <B>-e</B> option to the
				6429	<B>read</B> builtin.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	6430	By default, the line editing commands are similar to those of Emacs.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6431	A vi-style line editing interface is also available.
				6432	Line editing can be enabled at any time using the
				6433	<B>-o emacs</B>
				6434
				6435	or
				6436	<B>-o vi</B>
				6437
				6438	options to the
				6439	<B>set</B>
				6440
				6441	builtin (see
				6442	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				6443
				6444	</FONT>
				6445	below).
				6446	To turn off line editing after the shell is running, use the
				6447	<B>+o emacs</B>
				6448
				6449	or
				6450	<B>+o vi</B>
				6451
				6452	options to the
				6453	<B>set</B>
				6454
				6455	builtin.
				6456	<A NAME="lbCG"> </A>
				6457	<H4>Readline Notation</H4>
				6458
				6459	<P>
				6460
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	6461	In this section, the Emacs-style notation is used to denote
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6462	keystrokes. Control keys are denoted by C-<I>key</I>, e.g., C-n
				6463	means Control-N. Similarly,
				6464	<I>meta</I>
				6465
				6466	keys are denoted by M-<I>key</I>, so M-x means Meta-X. (On keyboards
				6467	without a
				6468	<I>meta</I>
				6469
				6470	key, M-<I>x</I> means ESC <I>x</I>, i.e., press the Escape key
				6471	then the
				6472	<I>x</I>
				6473
				6474	key. This makes ESC the <I>meta prefix</I>.
				6475	The combination M-C-<I>x</I> means ESC-Control-<I>x</I>,
				6476	or press the Escape key
				6477	then hold the Control key while pressing the
				6478	<I>x</I>
				6479
				6480	key.)
				6481	<P>
				6482
				6483	Readline commands may be given numeric
				6484	<I>arguments</I>,
				6485
				6486	which normally act as a repeat count.
				6487	Sometimes, however, it is the sign of the argument that is significant.
				6488	Passing a negative argument to a command that acts in the forward
				6489	direction (e.g., <B>kill-line</B>) causes that command to act in a
				6490	backward direction.
				6491	Commands whose behavior with arguments deviates from this are noted
				6492	below.
				6493	<P>
				6494
				6495	When a command is described as <I>killing</I> text, the text
				6496	deleted is saved for possible future retrieval
				6497	(<I>yanking</I>). The killed text is saved in a
				6498	<I>kill ring</I>. Consecutive kills cause the text to be
				6499	accumulated into one unit, which can be yanked all at once.
				6500	Commands which do not kill text separate the chunks of text
				6501	on the kill ring.
				6502	<A NAME="lbCH"> </A>
				6503	<H4>Readline Initialization</H4>
				6504
				6505	<P>
				6506
				6507	Readline is customized by putting commands in an initialization
				6508	file (the <I>inputrc</I> file).
				6509	The name of this file is taken from the value of the
				6510	<FONT SIZE=-1><B>INPUTRC</B>
				6511
				6512	</FONT>
				6513	variable. If that variable is unset, the default is
				6514	<A HREF="file:~/.inputrc"><I>~/.inputrc</I></A>.
				6515
				6516	When a program which uses the readline library starts up, the
				6517	initialization file is read, and the key bindings and variables
				6518	are set.
				6519	There are only a few basic constructs allowed in the
				6520	readline initialization file.
				6521	Blank lines are ignored.
				6522	Lines beginning with a <B>#</B> are comments.
				6523	Lines beginning with a <B>$</B> indicate conditional constructs.
				6524	Other lines denote key bindings and variable settings.
				6525	<P>
				6526
				6527	The default key-bindings may be changed with an
				6528	<I>inputrc </I>
				6529
				6530	file.
				6531	Other programs that use this library may add their own commands
				6532	and bindings.
				6533	<P>
				6534
				6535	For example, placing
				6536	<DL COMPACT><DT><DD>
				6537	<P>
				6538
				6539	M-Control-u: universal-argument
				6540	</DL>
				6541
				6542	or
				6543	<DL COMPACT><DT><DD>
				6544	C-Meta-u: universal-argument
				6545	</DL>
				6546
				6547	into the
				6548	<I>inputrc</I>
				6549
				6550	would make M-C-u execute the readline command
				6551	<I>universal-argument</I>.
				6552
				6553	<P>
				6554
				6555	The following symbolic character names are recognized:
				6556	<I>RUBOUT</I>,
				6557
				6558	<I>DEL</I>,
				6559
				6560	<I>ESC</I>,
				6561
				6562	<I>LFD</I>,
				6563
				6564	<I>NEWLINE</I>,
				6565
				6566	<I>RET</I>,
				6567
				6568	<I>RETURN</I>,
				6569
				6570	<I>SPC</I>,
				6571
				6572	<I>SPACE</I>,
				6573
				6574	and
				6575	<I>TAB</I>.
				6576
				6577	<P>
				6578
				6579	In addition to command names, readline allows keys to be bound
				6580	to a string that is inserted when the key is pressed (a <I>macro</I>).
				6581	<A NAME="lbCI"> </A>
				6582	<H4>Readline Key Bindings</H4>
				6583
				6584	<P>
				6585
				6586	The syntax for controlling key bindings in the
				6587	<I>inputrc</I>
				6588
				6589	file is simple. All that is required is the name of the
				6590	command or the text of a macro and a key sequence to which
				6591	it should be bound. The name may be specified in one of two ways:
				6592	as a symbolic key name, possibly with <I>Meta-</I> or <I>Control-</I>
				6593	prefixes, or as a key sequence.
				6594	<P>
				6595
				6596	When using the form <B>keyname</B>:<I>function-name</I> or <I>macro</I>,
				6597	<I>keyname</I>
				6598
				6599	is the name of a key spelled out in English. For example:
				6600	<P>
				6601	<DL COMPACT><DT><DD>
				6602	Control-u: universal-argument
				6603	<BR>
				6604
				6605	Meta-Rubout: backward-kill-word
				6606	<BR>
				6607
				6608	Control-o: "> output"
				6609	</DL>
				6610
				6611	<P>
				6612
				6613	In the above example,
				6614	<I>C-u</I>
				6615
				6616	is bound to the function
				6617	<B>universal-argument</B>,
				6618
				6619	<I>M-DEL</I>
				6620
				6621	is bound to the function
				6622	<B>backward-kill-word</B>,
				6623
				6624	and
				6625	<I>C-o</I>
				6626
				6627	is bound to run the macro
				6628	expressed on the right hand side (that is, to insert the text
				6629	<TT>> output</TT>
				6630
				6631	into the line).
				6632	<P>
				6633
				6634	In the second form, <B>"keyseq"</B>:<I>function-name</I> or <I>macro</I>,
				6635	<B>keyseq</B>
				6636
				6637	differs from
				6638	<B>keyname</B>
				6639
				6640	above in that strings denoting
				6641	an entire key sequence may be specified by placing the sequence
				6642	within double quotes. Some GNU Emacs style key escapes can be
				6643	used, as in the following example, but the symbolic character names
				6644	are not recognized.
				6645	<P>
				6646	<DL COMPACT><DT><DD>
				6647	"\C-u": universal-argument
				6648	<BR>
				6649
				6650	"\C-x\C-r": re-read-init-file
				6651	<BR>
				6652
				6653	"\e[11~": "Function Key 1"
				6654	</DL>
				6655
				6656	<P>
				6657
				6658	In this example,
				6659	<I>C-u</I>
				6660
				6661	is again bound to the function
				6662	<B>universal-argument</B>.
				6663
				6664	<I>C-x C-r</I>
				6665
				6666	is bound to the function
				6667	<B>re-read-init-file</B>,
				6668
				6669	and
				6670	<I>ESC [ 1 1 ~</I>
				6671
				6672	is bound to insert the text
				6673	<TT>Function Key 1</TT>.
				6674
				6675	<P>
				6676
				6677	The full set of GNU Emacs style escape sequences is
				6678	<DL COMPACT><DT><DD>
				6679
				6680	<DL COMPACT>
				6681	<DT><B>\C-</B>
				6682
				6683	<DD>
				6684	control prefix
				6685	<DT><B>\M-</B>
				6686
				6687	<DD>
				6688	meta prefix
				6689	<DT><B>\e</B>
				6690
				6691	<DD>
				6692	an escape character
				6693	<DT><B>\\</B>
				6694
				6695	<DD>
				6696	backslash
				6697	<DT><B>\</B>
				6698
				6699	<DD>
				6700	literal "
				6701	<DT><B>\aq</B>
				6702
				6703	<DD>
				6704	literal aq
				6705	</DL></DL>
				6706
				6707
				6708	<P>
				6709
				6710	In addition to the GNU Emacs style escape sequences, a second
				6711	set of backslash escapes is available:
				6712	<DL COMPACT><DT><DD>
				6713
				6714	<DL COMPACT>
				6715	<DT><B>\a</B>
				6716
				6717	<DD>
				6718	alert (bell)
				6719	<DT><B>\b</B>
				6720
				6721	<DD>
				6722	backspace
				6723	<DT><B>\d</B>
				6724
				6725	<DD>
				6726	delete
				6727	<DT><B>\f</B>
				6728
				6729	<DD>
				6730	form feed
				6731	<DT><B>\n</B>
				6732
				6733	<DD>
				6734	newline
				6735	<DT><B>\r</B>
				6736
				6737	<DD>
				6738	carriage return
				6739	<DT><B>\t</B>
				6740
				6741	<DD>
				6742	horizontal tab
				6743	<DT><B>\v</B>
				6744
				6745	<DD>
				6746	vertical tab
				6747	<DT><B>\</B><I>nnn</I>
				6748
				6749	<DD>
				6750	the eight-bit character whose value is the octal value <I>nnn</I>
				6751	(one to three digits)
				6752	<DT><B>\x</B><I>HH</I>
				6753
				6754	<DD>
				6755	the eight-bit character whose value is the hexadecimal value <I>HH</I>
				6756	(one or two hex digits)
				6757	</DL></DL>
				6758
				6759
				6760	<P>
				6761
				6762	When entering the text of a macro, single or double quotes must
				6763	be used to indicate a macro definition.
				6764	Unquoted text is assumed to be a function name.
				6765	In the macro body, the backslash escapes described above are expanded.
				6766	Backslash will quote any other character in the macro text,
				6767	including " and aq.
				6768	<P>
				6769
				6770	<B>Bash</B>
				6771
				6772	allows the current readline key bindings to be displayed or modified
				6773	with the
				6774	<B>bind</B>
				6775
				6776	builtin command. The editing mode may be switched during interactive
				6777	use by using the
				6778	<B>-o</B>
				6779
				6780	option to the
				6781	<B>set</B>
				6782
				6783	builtin command (see
				6784	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				6785
				6786	</FONT>
				6787	below).
				6788	<A NAME="lbCJ"> </A>
				6789	<H4>Readline Variables</H4>
				6790
				6791	<P>
				6792
				6793	Readline has variables that can be used to further customize its
				6794	behavior. A variable may be set in the
				6795	<I>inputrc</I>
				6796
				6797	file with a statement of the form
				6798	<DL COMPACT><DT><DD>
				6799	<P>
				6800
				6801	<B>set</B> <I>variable-name</I> <I>value</I>
				6802	</DL>
				6803
				6804	<P>
				6805
				6806	Except where noted, readline variables can take the values
				6807	<B>On</B>
				6808
				6809	or
				6810	<B>Off</B>
				6811
				6812	(without regard to case).
				6813	Unrecognized variable names are ignored.
				6814	When a variable value is read, empty or null values, "on" (case-insensitive),
				6815	and "1" are equivalent to <B>On</B>. All other values are equivalent to
				6816	<B>Off</B>.
				6817	The variables and their default values are:
				6818	<P>
				6819
				6820
				6821	<DL COMPACT>
				6822	<DT><B>bell-style (audible)</B>
				6823
				6824	<DD>
				6825	Controls what happens when readline wants to ring the terminal bell.
				6826	If set to <B>none</B>, readline never rings the bell. If set to
				6827	<B>visible</B>, readline uses a visible bell if one is available.
				6828	If set to <B>audible</B>, readline attempts to ring the terminal's bell.
				6829	<DT><B>bind-tty-special-chars (On)</B>
				6830
				6831	<DD>
				6832	If set to <B>On</B>, readline attempts to bind the control characters
				6833	treated specially by the kernel's terminal driver to their readline
				6834	equivalents.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	6835	<DT><B>colored-stats (Off)</B>
				6836
				6837	<DD>
				6838	If set to <B>On</B>, readline displays possible completions using different
				6839	colors to indicate their file type.
				6840	The color definitions are taken from the value of the <B>LS_COLORS</B>
				6841	environment variable.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6842	<DT><B>comment-begin (``#'')</B>
				6843
				6844	<DD>
				6845	The string that is inserted when the readline
				6846	<B>insert-comment</B>
				6847
				6848	command is executed.
				6849	This command is bound to
				6850	<B>M-#</B>
				6851
				6852	in emacs mode and to
				6853	<B>#</B>
				6854
				6855	in vi command mode.
				6856	<DT><B>completion-ignore-case (Off)</B>
				6857
				6858	<DD>
				6859	If set to <B>On</B>, readline performs filename matching and completion
				6860	in a case-insensitive fashion.
				6861	<DT><B>completion-prefix-display-length (0)</B>
				6862
				6863	<DD>
				6864	The length in characters of the common prefix of a list of possible
				6865	completions that is displayed without modification. When set to a
				6866	value greater than zero, common prefixes longer than this value are
				6867	replaced with an ellipsis when displaying possible completions.
				6868	<DT><B>completion-query-items (100)</B>
				6869
				6870	<DD>
				6871	This determines when the user is queried about viewing
				6872	the number of possible completions
				6873	generated by the <B>possible-completions</B> command.
				6874	It may be set to any integer value greater than or equal to
				6875	zero. If the number of possible completions is greater than
				6876	or equal to the value of this variable, the user is asked whether
				6877	or not he wishes to view them; otherwise they are simply listed
				6878	on the terminal.
				6879	<DT><B>convert-meta (On)</B>
				6880
				6881	<DD>
				6882	If set to <B>On</B>, readline will convert characters with the
				6883	eighth bit set to an ASCII key sequence
				6884	by stripping the eighth bit and prefixing an
				6885	escape character (in effect, using escape as the <I>meta prefix</I>).
				6886	<DT><B>disable-completion (Off)</B>
				6887
				6888	<DD>
				6889	If set to <B>On</B>, readline will inhibit word completion. Completion
				6890	characters will be inserted into the line as if they had been
				6891	mapped to <B>self-insert</B>.
				6892	<DT><B>editing-mode (emacs)</B>
				6893
				6894	<DD>
				6895	Controls whether readline begins with a set of key bindings similar
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	6896	to <I>Emacs</I> or <I>vi</I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6897	<B>editing-mode</B>
				6898
				6899	can be set to either
				6900	<B>emacs</B>
				6901
				6902	or
				6903	<B>vi</B>.
				6904
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	6905	<DT><B>echo-control-characters (On)</B>
				6906
				6907	<DD>
				6908	When set to <B>On</B>, on operating systems that indicate they support it,
				6909	readline echoes a character corresponding to a signal generated from the
				6910	keyboard.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6911	<DT><B>enable-keypad (Off)</B>
				6912
				6913	<DD>
				6914	When set to <B>On</B>, readline will try to enable the application
				6915	keypad when it is called. Some systems need this to enable the
				6916	arrow keys.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	6917	<DT><B>enable-meta-key (On)</B>
				6918
				6919	<DD>
				6920	When set to <B>On</B>, readline will try to enable any meta modifier
				6921	key the terminal claims to support when it is called. On many terminals,
				6922	the meta key is used to send eight-bit characters.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6923	<DT><B>expand-tilde (Off)</B>
				6924
				6925	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	6926	If set to <B>On</B>, tilde expansion is performed when readline
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6927	attempts word completion.
				6928	<DT><B>history-preserve-point (Off)</B>
				6929
				6930	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	6931	If set to <B>On</B>, the history code attempts to place point at the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6932	same location on each history line retrieved with <B>previous-history</B>
				6933	or <B>next-history</B>.
				6934	<DT><B>history-size (0)</B>
				6935
				6936	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	6937	Set the maximum number of history entries saved in the history list.
				6938	If set to zero, any existing history entries are deleted and no new entries
				6939	are saved.
				6940	If set to a value less than zero, the number of history entries is not
				6941	limited.
				6942	By default, the number of history entries is not limited.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6943	<DT><B>horizontal-scroll-mode (Off)</B>
				6944
				6945	<DD>
				6946	When set to <B>On</B>, makes readline use a single line for display,
				6947	scrolling the input horizontally on a single screen line when it
				6948	becomes longer than the screen width rather than wrapping to a new line.
				6949	<DT><B>input-meta (Off)</B>
				6950
				6951	<DD>
				6952	If set to <B>On</B>, readline will enable eight-bit input (that is,
				6953	it will not strip the high bit from the characters it reads),
				6954	regardless of what the terminal claims it can support. The name
				6955	<B>meta-flag</B>
				6956
				6957	is a synonym for this variable.
				6958	<DT><B>isearch-terminators (``C-[C-J'')</B>
				6959
				6960	<DD>
				6961	The string of characters that should terminate an incremental
				6962	search without subsequently executing the character as a command.
				6963	If this variable has not been given a value, the characters
				6964	<I>ESC</I> and <I>C-J</I> will terminate an incremental search.
				6965	<DT><B>keymap (emacs)</B>
				6966
				6967	<DD>
				6968	Set the current readline keymap. The set of valid keymap names is
				6969	<I>emacs, emacs-standard, emacs-meta, emacs-ctlx, vi,
				6970	vi-command</I>, and
				6971	<I>vi-insert</I>.
				6972
				6973	<I>vi</I> is equivalent to <I>vi-command</I>; <I>emacs</I> is
				6974	equivalent to <I>emacs-standard</I>. The default value is
				6975	<I>emacs</I>;
				6976
				6977	the value of
				6978	<B>editing-mode</B>
				6979
				6980	also affects the default keymap.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	6981	<DT><B>keyseq-timeout (500)</B>
				6982
				6983	<DD>
				6984	Specifies the duration <I>readline</I> will wait for a character when reading an
				6985	ambiguous key sequence (one that can form a complete key sequence using
				6986	the input read so far, or can take additional input to complete a longer
				6987	key sequence).
				6988	If no input is received within the timeout, <I>readline</I> will use the shorter
				6989	but complete key sequence.
				6990	The value is specified in milliseconds, so a value of 1000 means that
				6991	<I>readline</I> will wait one second for additional input.
				6992	If this variable is set to a value less than or equal to zero, or to a
				6993	non-numeric value, <I>readline</I> will wait until another key is pressed to
				6994	decide which key sequence to complete.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	6995	<DT><B>mark-directories (On)</B>
				6996
				6997	<DD>
				6998	If set to <B>On</B>, completed directory names have a slash
				6999	appended.
				7000	<DT><B>mark-modified-lines (Off)</B>
				7001
				7002	<DD>
				7003	If set to <B>On</B>, history lines that have been modified are displayed
				7004	with a preceding asterisk (<B>*</B>).
				7005	<DT><B>mark-symlinked-directories (Off)</B>
				7006
				7007	<DD>
				7008	If set to <B>On</B>, completed names which are symbolic links to directories
				7009	have a slash appended (subject to the value of
				7010	<B>mark-directories</B>).
				7011	<DT><B>match-hidden-files (On)</B>
				7012
				7013	<DD>
				7014	This variable, when set to <B>On</B>, causes readline to match files whose
				7015	names begin with a `.' (hidden files) when performing filename
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7016	completion.
				7017	If set to <B>Off</B>, the leading `.' must be
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7018	supplied by the user in the filename to be completed.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7019	<DT><B>menu-complete-display-prefix (Off)</B>
				7020
				7021	<DD>
				7022	If set to <B>On</B>, menu completion displays the common prefix of the
				7023	list of possible completions (which may be empty) before cycling through
				7024	the list.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7025	<DT><B>output-meta (Off)</B>
				7026
				7027	<DD>
				7028	If set to <B>On</B>, readline will display characters with the
				7029	eighth bit set directly rather than as a meta-prefixed escape
				7030	sequence.
				7031	<DT><B>page-completions (On)</B>
				7032
				7033	<DD>
				7034	If set to <B>On</B>, readline uses an internal <I>more</I>-like pager
				7035	to display a screenful of possible completions at a time.
				7036	<DT><B>print-completions-horizontally (Off)</B>
				7037
				7038	<DD>
				7039	If set to <B>On</B>, readline will display completions with matches
				7040	sorted horizontally in alphabetical order, rather than down the screen.
				7041	<DT><B>revert-all-at-newline (Off)</B>
				7042
				7043	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7044	If set to <B>On</B>, readline will undo all changes to history lines
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7045	before returning when <B>accept-line</B> is executed. By default,
				7046	history lines may be modified and retain individual undo lists across
				7047	calls to <B>readline</B>.
				7048	<DT><B>show-all-if-ambiguous (Off)</B>
				7049
				7050	<DD>
				7051	This alters the default behavior of the completion functions. If
				7052	set to
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7053	<B>On</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7054
				7055	words which have more than one possible completion cause the
				7056	matches to be listed immediately instead of ringing the bell.
				7057	<DT><B>show-all-if-unmodified (Off)</B>
				7058
				7059	<DD>
				7060	This alters the default behavior of the completion functions in
				7061	a fashion similar to <B>show-all-if-ambiguous</B>.
				7062	If set to
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7063	<B>On</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7064
				7065	words which have more than one possible completion without any
				7066	possible partial completion (the possible completions don't share
				7067	a common prefix) cause the matches to be listed immediately instead
				7068	of ringing the bell.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7069	<DT><B>show-mode-in-prompt (Off)</B>
				7070
				7071	<DD>
				7072	If set to <B>On</B>, add a character to the beginning of the prompt
				7073	indicating the editing mode: emacs (@), vi command (:) or vi
				7074	insertion (+).
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	7075	<DT><B>skip-completed-text (Off)</B>
				7076
				7077	<DD>
				7078	If set to <B>On</B>, this alters the default completion behavior when
				7079	inserting a single match into the line. It's only active when
				7080	performing completion in the middle of a word. If enabled, readline
				7081	does not insert characters from the completion that match characters
				7082	after point in the word being completed, so portions of the word
				7083	following the cursor are not duplicated.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7084	<DT><B>visible-stats (Off)</B>
				7085
				7086	<DD>
				7087	If set to <B>On</B>, a character denoting a file's type as reported
				7088	by <I>stat</I>(2) is appended to the filename when listing possible
				7089	completions.
				7090
				7091	</DL>
				7092	<A NAME="lbCK"> </A>
				7093	<H4>Readline Conditional Constructs</H4>
				7094
				7095	<P>
				7096
				7097	Readline implements a facility similar in spirit to the conditional
				7098	compilation features of the C preprocessor which allows key
				7099	bindings and variable settings to be performed as the result
				7100	of tests. There are four parser directives used.
				7101	<DL COMPACT>
				7102	<DT><B>$if</B><DD>
				7103	The
				7104	<B>$if</B>
				7105
				7106	construct allows bindings to be made based on the
				7107	editing mode, the terminal being used, or the application using
				7108	readline. The text of the test extends to the end of the line;
				7109	no characters are required to isolate it.
				7110	<DL COMPACT><DT><DD>
				7111	<DL COMPACT>
				7112	<DT><B>mode</B><DD>
				7113	The <B>mode=</B> form of the <B>$if</B> directive is used to test
				7114	whether readline is in emacs or vi mode.
				7115	This may be used in conjunction
				7116	with the <B>set keymap</B> command, for instance, to set bindings in
				7117	the <I>emacs-standard</I> and <I>emacs-ctlx</I> keymaps only if
				7118	readline is starting out in emacs mode.
				7119	<DT><B>term</B><DD>
				7120	The <B>term=</B> form may be used to include terminal-specific
				7121	key bindings, perhaps to bind the key sequences output by the
				7122	terminal's function keys. The word on the right side of the
				7123	<B>=</B>
				7124
				7125	is tested against the both full name of the terminal and the portion
				7126	of the terminal name before the first <B>-</B>. This allows
				7127	<I>sun</I>
				7128
				7129	to match both
				7130	<I>sun</I>
				7131
				7132	and
				7133	<I>sun-cmd</I>,
				7134
				7135	for instance.
				7136	<DT><B>application</B><DD>
				7137	The <B>application</B> construct is used to include
				7138	application-specific settings. Each program using the readline
				7139	library sets the <I>application name</I>, and an initialization
				7140	file can test for a particular value.
				7141	This could be used to bind key sequences to functions useful for
				7142	a specific program. For instance, the following command adds a
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7143	key sequence that quotes the current or previous word in <B>bash</B>:
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7144	<P>
				7145	<DL COMPACT><DT><DD>
				7146	<PRE>
				7147	<B>$if</B> Bash
				7148	# Quote the current or previous word
				7149	"\C-xq": "\eb\"\ef\""
				7150	<B>$endif</B>
				7151	</PRE>
				7152
				7153	</DL>
				7154
				7155	</DL></DL>
				7156
				7157	<DT><B>$endif</B><DD>
				7158	This command, as seen in the previous example, terminates an
				7159	<B>$if</B> command.
				7160	<DT><B>$else</B><DD>
				7161	Commands in this branch of the <B>$if</B> directive are executed if
				7162	the test fails.
				7163	<DT><B>$include</B><DD>
				7164	This directive takes a single filename as an argument and reads commands
				7165	and bindings from that file. For example, the following directive
				7166	would read <A HREF="file:/etc/inputrc"><I>/etc/inputrc</I></A>:
				7167	<P>
				7168	<DL COMPACT><DT><DD>
				7169	<PRE>
				7170	<B>$include</B> <A HREF="file:/etc/inputrc"><I>/etc/inputrc</I></A>
				7171	</PRE>
				7172
				7173	</DL>
				7174
				7175	</DL>
				7176	<A NAME="lbCL"> </A>
				7177	<H4>Searching</H4>
				7178
				7179	<P>
				7180
				7181	Readline provides commands for searching through the command history
				7182	(see
				7183	<FONT SIZE=-1><B>HISTORY</B>
				7184
				7185	</FONT>
				7186	below) for lines containing a specified string.
				7187	There are two search modes:
				7188	<I>incremental</I>
				7189
				7190	and
				7191	<I>non-incremental</I>.
				7192
				7193	<P>
				7194
				7195	Incremental searches begin before the user has finished typing the
				7196	search string.
				7197	As each character of the search string is typed, readline displays
				7198	the next entry from the history matching the string typed so far.
				7199	An incremental search requires only as many characters as needed to
				7200	find the desired history entry.
				7201	The characters present in the value of the <B>isearch-terminators</B>
				7202	variable are used to terminate an incremental search.
				7203	If that variable has not been assigned a value the Escape and
				7204	Control-J characters will terminate an incremental search.
				7205	Control-G will abort an incremental search and restore the original
				7206	line.
				7207	When the search is terminated, the history entry containing the
				7208	search string becomes the current line.
				7209	<P>
				7210
				7211	To find other matching entries in the history list, type Control-S or
				7212	Control-R as appropriate.
				7213	This will search backward or forward in the history for the next
				7214	entry matching the search string typed so far.
				7215	Any other key sequence bound to a readline command will terminate
				7216	the search and execute that command.
				7217	For instance, a <I>newline</I> will terminate the search and accept
				7218	the line, thereby executing the command from the history list.
				7219	<P>
				7220
				7221	Readline remembers the last incremental search string. If two
				7222	Control-Rs are typed without any intervening characters defining a
				7223	new search string, any remembered search string is used.
				7224	<P>
				7225
				7226	Non-incremental searches read the entire search string before starting
				7227	to search for matching history lines. The search string may be
				7228	typed by the user or be part of the contents of the current line.
				7229	<A NAME="lbCM"> </A>
				7230	<H4>Readline Command Names</H4>
				7231
				7232	<P>
				7233
				7234	The following is a list of the names of the commands and the default
				7235	key sequences to which they are bound.
				7236	Command names without an accompanying key sequence are unbound by default.
				7237	In the following descriptions, <I>point</I> refers to the current cursor
				7238	position, and <I>mark</I> refers to a cursor position saved by the
				7239	<B>set-mark</B> command.
				7240	The text between the point and mark is referred to as the <I>region</I>.
				7241	<A NAME="lbCN"> </A>
				7242	<H4>Commands for Moving</H4>
				7243
				7244	<P>
				7245
				7246
				7247	<DL COMPACT>
				7248	<DT><B>beginning-of-line (C-a)</B>
				7249
				7250	<DD>
				7251	Move to the start of the current line.
				7252	<DT><B>end-of-line (C-e)</B>
				7253
				7254	<DD>
				7255	Move to the end of the line.
				7256	<DT><B>forward-char (C-f)</B>
				7257
				7258	<DD>
				7259	Move forward a character.
				7260	<DT><B>backward-char (C-b)</B>
				7261
				7262	<DD>
				7263	Move back a character.
				7264	<DT><B>forward-word (M-f)</B>
				7265
				7266	<DD>
				7267	Move forward to the end of the next word. Words are composed of
				7268	alphanumeric characters (letters and digits).
				7269	<DT><B>backward-word (M-b)</B>
				7270
				7271	<DD>
				7272	Move back to the start of the current or previous word.
				7273	Words are composed of alphanumeric characters (letters and digits).
				7274	<DT><B>shell-forward-word</B>
				7275
				7276	<DD>
				7277	Move forward to the end of the next word.
				7278	Words are delimited by non-quoted shell metacharacters.
				7279	<DT><B>shell-backward-word</B>
				7280
				7281	<DD>
				7282	Move back to the start of the current or previous word.
				7283	Words are delimited by non-quoted shell metacharacters.
				7284	<DT><B>clear-screen (C-l)</B>
				7285
				7286	<DD>
				7287	Clear the screen leaving the current line at the top of the screen.
				7288	With an argument, refresh the current line without clearing the
				7289	screen.
				7290	<DT><B>redraw-current-line</B>
				7291
				7292	<DD>
				7293	Refresh the current line.
				7294
				7295	</DL>
				7296	<A NAME="lbCO"> </A>
				7297	<H4>Commands for Manipulating the History</H4>
				7298
				7299	<P>
				7300
				7301
				7302	<DL COMPACT>
				7303	<DT><B>accept-line (Newline, Return)</B>
				7304
				7305	<DD>
				7306	Accept the line regardless of where the cursor is. If this line is
				7307	non-empty, add it to the history list according to the state of the
				7308	<FONT SIZE=-1><B>HISTCONTROL</B>
				7309
				7310	</FONT>
				7311	variable. If the line is a modified history
				7312	line, then restore the history line to its original state.
				7313	<DT><B>previous-history (C-p)</B>
				7314
				7315	<DD>
				7316	Fetch the previous command from the history list, moving back in
				7317	the list.
				7318	<DT><B>next-history (C-n)</B>
				7319
				7320	<DD>
				7321	Fetch the next command from the history list, moving forward in the
				7322	list.
				7323	<DT><B>beginning-of-history (M-<)</B>
				7324
				7325	<DD>
				7326	Move to the first line in the history.
				7327	<DT><B>end-of-history (M->)</B>
				7328
				7329	<DD>
				7330	Move to the end of the input history, i.e., the line currently being
				7331	entered.
				7332	<DT><B>reverse-search-history (C-r)</B>
				7333
				7334	<DD>
				7335	Search backward starting at the current line and moving `up' through
				7336	the history as necessary. This is an incremental search.
				7337	<DT><B>forward-search-history (C-s)</B>
				7338
				7339	<DD>
				7340	Search forward starting at the current line and moving `down' through
				7341	the history as necessary. This is an incremental search.
				7342	<DT><B>non-incremental-reverse-search-history (M-p)</B>
				7343
				7344	<DD>
				7345	Search backward through the history starting at the current line
				7346	using a non-incremental search for a string supplied by the user.
				7347	<DT><B>non-incremental-forward-search-history (M-n)</B>
				7348
				7349	<DD>
				7350	Search forward through the history using a non-incremental search for
				7351	a string supplied by the user.
				7352	<DT><B>history-search-forward</B>
				7353
				7354	<DD>
				7355	Search forward through the history for the string of characters
				7356	between the start of the current line and the point.
				7357	This is a non-incremental search.
				7358	<DT><B>history-search-backward</B>
				7359
				7360	<DD>
				7361	Search backward through the history for the string of characters
				7362	between the start of the current line and the point.
				7363	This is a non-incremental search.
				7364	<DT><B>yank-nth-arg (M-C-y)</B>
				7365
				7366	<DD>
				7367	Insert the first argument to the previous command (usually
				7368	the second word on the previous line) at point.
				7369	With an argument
				7370	<I>n</I>,
				7371
				7372	insert the <I>n</I>th word from the previous command (the words
				7373	in the previous command begin with word 0). A negative argument
				7374	inserts the <I>n</I>th word from the end of the previous command.
				7375	Once the argument <I>n</I> is computed, the argument is extracted
				7376	as if the "!<I>n</I>" history expansion had been specified.
				7377	<DT><B>yank-last-arg (M-., M-_)</B>
				7378
				7379	<DD>
				7380	Insert the last argument to the previous command (the last word of
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7381	the previous history entry).
				7382	With a numeric argument, behave exactly like <B>yank-nth-arg</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7383	Successive calls to <B>yank-last-arg</B> move back through the history
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7384	list, inserting the last word (or the word specified by the argument to
				7385	the first call) of each line in turn.
				7386	Any numeric argument supplied to these successive calls determines
				7387	the direction to move through the history. A negative argument switches
				7388	the direction through the history (back or forward).
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7389	The history expansion facilities are used to extract the last word,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7390	as if the "!$" history expansion had been specified.
				7391	<DT><B>shell-expand-line (M-C-e)</B>
				7392
				7393	<DD>
				7394	Expand the line as the shell does. This
				7395	performs alias and history expansion as well as all of the shell
				7396	word expansions. See
				7397	<FONT SIZE=-1><B>HISTORY EXPANSION</B>
				7398
				7399	</FONT>
				7400	below for a description of history expansion.
				7401	<DT><B>history-expand-line (M-^)</B>
				7402
				7403	<DD>
				7404	Perform history expansion on the current line.
				7405	See
				7406	<FONT SIZE=-1><B>HISTORY EXPANSION</B>
				7407
				7408	</FONT>
				7409	below for a description of history expansion.
				7410	<DT><B>magic-space</B>
				7411
				7412	<DD>
				7413	Perform history expansion on the current line and insert a space.
				7414	See
				7415	<FONT SIZE=-1><B>HISTORY EXPANSION</B>
				7416
				7417	</FONT>
				7418	below for a description of history expansion.
				7419	<DT><B>alias-expand-line</B>
				7420
				7421	<DD>
				7422	Perform alias expansion on the current line.
				7423	See
				7424	<FONT SIZE=-1><B>ALIASES</B>
				7425
				7426	</FONT>
				7427	above for a description of alias expansion.
				7428	<DT><B>history-and-alias-expand-line</B>
				7429
				7430	<DD>
				7431	Perform history and alias expansion on the current line.
				7432	<DT><B>insert-last-argument (M-., M-_)</B>
				7433
				7434	<DD>
				7435	A synonym for <B>yank-last-arg</B>.
				7436	<DT><B>operate-and-get-next (C-o)</B>
				7437
				7438	<DD>
				7439	Accept the current line for execution and fetch the next line
				7440	relative to the current line from the history for editing. Any
				7441	argument is ignored.
				7442	<DT><B>edit-and-execute-command (C-xC-e)</B>
				7443
				7444	<DD>
				7445	Invoke an editor on the current command line, and execute the result as shell
				7446	commands.
				7447	<B>Bash</B> attempts to invoke
				7448	<FONT SIZE=-1><B>$VISUAL</B>,
				7449
				7450	</FONT>
				7451	<FONT SIZE=-1><B>$EDITOR</B>,
				7452
				7453	</FONT>
				7454	and <I>emacs</I> as the editor, in that order.
				7455
				7456	</DL>
				7457	<A NAME="lbCP"> </A>
				7458	<H4>Commands for Changing Text</H4>
				7459
				7460	<P>
				7461
				7462
				7463	<DL COMPACT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7464	<DT><B></B><I>end-of-file</I> (usually C-d)
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7465
				7466	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7467	The character indicating end-of-file as set, for example, by
				7468	<TT>stty</TT>.
				7469
				7470	If this character is read when there are no characters
				7471	on the line, and point is at the beginning of the line, Readline
				7472	interprets it as the end of input and returns
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7473	<FONT SIZE=-1><B>EOF</B>.
				7474
				7475	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7476	<DT><B>delete-char (C-d)</B>
				7477
				7478	<DD>
				7479	Delete the character at point.
				7480	If this function is bound to the
				7481	same character as the tty <B>EOF</B> character, as <B>C-d</B>
				7482	commonly is, see above for the effects.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7483	<DT><B>backward-delete-char (Rubout)</B>
				7484
				7485	<DD>
				7486	Delete the character behind the cursor. When given a numeric argument,
				7487	save the deleted text on the kill ring.
				7488	<DT><B>forward-backward-delete-char</B>
				7489
				7490	<DD>
				7491	Delete the character under the cursor, unless the cursor is at the
				7492	end of the line, in which case the character behind the cursor is
				7493	deleted.
				7494	<DT><B>quoted-insert (C-q, C-v)</B>
				7495
				7496	<DD>
				7497	Add the next character typed to the line verbatim. This is
				7498	how to insert characters like <B>C-q</B>, for example.
				7499	<DT><B>tab-insert (C-v TAB)</B>
				7500
				7501	<DD>
				7502	Insert a tab character.
				7503	<DT><B>self-insert (a, b, A, 1, !, ...)</B>
				7504
				7505	<DD>
				7506	Insert the character typed.
				7507	<DT><B>transpose-chars (C-t)</B>
				7508
				7509	<DD>
				7510	Drag the character before point forward over the character at point,
				7511	moving point forward as well.
				7512	If point is at the end of the line, then this transposes
				7513	the two characters before point.
				7514	Negative arguments have no effect.
				7515	<DT><B>transpose-words (M-t)</B>
				7516
				7517	<DD>
				7518	Drag the word before point past the word after point,
				7519	moving point over that word as well.
				7520	If point is at the end of the line, this transposes
				7521	the last two words on the line.
				7522	<DT><B>upcase-word (M-u)</B>
				7523
				7524	<DD>
				7525	Uppercase the current (or following) word. With a negative argument,
				7526	uppercase the previous word, but do not move point.
				7527	<DT><B>downcase-word (M-l)</B>
				7528
				7529	<DD>
				7530	Lowercase the current (or following) word. With a negative argument,
				7531	lowercase the previous word, but do not move point.
				7532	<DT><B>capitalize-word (M-c)</B>
				7533
				7534	<DD>
				7535	Capitalize the current (or following) word. With a negative argument,
				7536	capitalize the previous word, but do not move point.
				7537	<DT><B>overwrite-mode</B>
				7538
				7539	<DD>
				7540	Toggle overwrite mode. With an explicit positive numeric argument,
				7541	switches to overwrite mode. With an explicit non-positive numeric
				7542	argument, switches to insert mode. This command affects only
				7543	<B>emacs</B> mode; <B>vi</B> mode does overwrite differently.
				7544	Each call to <I>readline()</I> starts in insert mode.
				7545	In overwrite mode, characters bound to <B>self-insert</B> replace
				7546	the text at point rather than pushing the text to the right.
				7547	Characters bound to <B>backward-delete-char</B> replace the character
				7548	before point with a space. By default, this command is unbound.
				7549
				7550	</DL>
				7551	<A NAME="lbCQ"> </A>
				7552	<H4>Killing and Yanking</H4>
				7553
				7554	<P>
				7555
				7556
				7557	<DL COMPACT>
				7558	<DT><B>kill-line (C-k)</B>
				7559
				7560	<DD>
				7561	Kill the text from point to the end of the line.
				7562	<DT><B>backward-kill-line (C-x Rubout)</B>
				7563
				7564	<DD>
				7565	Kill backward to the beginning of the line.
				7566	<DT><B>unix-line-discard (C-u)</B>
				7567
				7568	<DD>
				7569	Kill backward from point to the beginning of the line.
				7570	The killed text is saved on the kill-ring.
				7571
				7572	<DT><B>kill-whole-line</B>
				7573
				7574	<DD>
				7575	Kill all characters on the current line, no matter where point is.
				7576	<DT><B>kill-word (M-d)</B>
				7577
				7578	<DD>
				7579	Kill from point to the end of the current word, or if between
				7580	words, to the end of the next word.
				7581	Word boundaries are the same as those used by <B>forward-word</B>.
				7582	<DT><B>backward-kill-word (M-Rubout)</B>
				7583
				7584	<DD>
				7585	Kill the word behind point.
				7586	Word boundaries are the same as those used by <B>backward-word</B>.
				7587	<DT><B>shell-kill-word (M-d)</B>
				7588
				7589	<DD>
				7590	Kill from point to the end of the current word, or if between
				7591	words, to the end of the next word.
				7592	Word boundaries are the same as those used by <B>shell-forward-word</B>.
				7593	<DT><B>shell-backward-kill-word (M-Rubout)</B>
				7594
				7595	<DD>
				7596	Kill the word behind point.
				7597	Word boundaries are the same as those used by <B>shell-backward-word</B>.
				7598	<DT><B>unix-word-rubout (C-w)</B>
				7599
				7600	<DD>
				7601	Kill the word behind point, using white space as a word boundary.
				7602	The killed text is saved on the kill-ring.
				7603	<DT><B>unix-filename-rubout</B>
				7604
				7605	<DD>
				7606	Kill the word behind point, using white space and the slash character
				7607	as the word boundaries.
				7608	The killed text is saved on the kill-ring.
				7609	<DT><B>delete-horizontal-space (M-\)</B>
				7610
				7611	<DD>
				7612	Delete all spaces and tabs around point.
				7613	<DT><B>kill-region</B>
				7614
				7615	<DD>
				7616	Kill the text in the current region.
				7617	<DT><B>copy-region-as-kill</B>
				7618
				7619	<DD>
				7620	Copy the text in the region to the kill buffer.
				7621	<DT><B>copy-backward-word</B>
				7622
				7623	<DD>
				7624	Copy the word before point to the kill buffer.
				7625	The word boundaries are the same as <B>backward-word</B>.
				7626	<DT><B>copy-forward-word</B>
				7627
				7628	<DD>
				7629	Copy the word following point to the kill buffer.
				7630	The word boundaries are the same as <B>forward-word</B>.
				7631	<DT><B>yank (C-y)</B>
				7632
				7633	<DD>
				7634	Yank the top of the kill ring into the buffer at point.
				7635	<DT><B>yank-pop (M-y)</B>
				7636
				7637	<DD>
				7638	Rotate the kill ring, and yank the new top. Only works following
				7639	<B>yank</B>
				7640
				7641	or
				7642	<B>yank-pop</B>.
				7643
				7644
				7645	</DL>
				7646	<A NAME="lbCR"> </A>
				7647	<H4>Numeric Arguments</H4>
				7648
				7649	<P>
				7650
				7651
				7652	<DL COMPACT>
				7653	<DT><B>digit-argument (M-0, M-1, ..., M--)</B>
				7654
				7655	<DD>
				7656	Add this digit to the argument already accumulating, or start a new
				7657	argument. M-- starts a negative argument.
				7658	<DT><B>universal-argument</B>
				7659
				7660	<DD>
				7661	This is another way to specify an argument.
				7662	If this command is followed by one or more digits, optionally with a
				7663	leading minus sign, those digits define the argument.
				7664	If the command is followed by digits, executing
				7665	<B>universal-argument</B>
				7666
				7667	again ends the numeric argument, but is otherwise ignored.
				7668	As a special case, if this command is immediately followed by a
				7669	character that is neither a digit or minus sign, the argument count
				7670	for the next command is multiplied by four.
				7671	The argument count is initially one, so executing this function the
				7672	first time makes the argument count four, a second time makes the
				7673	argument count sixteen, and so on.
				7674
				7675	</DL>
				7676	<A NAME="lbCS"> </A>
				7677	<H4>Completing</H4>
				7678
				7679	<P>
				7680
				7681
				7682	<DL COMPACT>
				7683	<DT><B>complete (TAB)</B>
				7684
				7685	<DD>
				7686	Attempt to perform completion on the text before point.
				7687	<B>Bash</B>
				7688
				7689	attempts completion treating the text as a variable (if the
				7690	text begins with <B>$</B>), username (if the text begins with
				7691	<B>~</B>), hostname (if the text begins with <B>@</B>), or
				7692	command (including aliases and functions) in turn. If none
				7693	of these produces a match, filename completion is attempted.
				7694	<DT><B>possible-completions (M-?)</B>
				7695
				7696	<DD>
				7697	List the possible completions of the text before point.
				7698	<DT><B>insert-completions (M-*)</B>
				7699
				7700	<DD>
				7701	Insert all completions of the text before point
				7702	that would have been generated by
				7703	<B>possible-completions</B>.
				7704	<DT><B>menu-complete</B>
				7705
				7706	<DD>
				7707	Similar to <B>complete</B>, but replaces the word to be completed
				7708	with a single match from the list of possible completions.
				7709	Repeated execution of <B>menu-complete</B> steps through the list
				7710	of possible completions, inserting each match in turn.
				7711	At the end of the list of completions, the bell is rung
				7712	(subject to the setting of <B>bell-style</B>)
				7713	and the original text is restored.
				7714	An argument of <I>n</I> moves <I>n</I> positions forward in the list
				7715	of matches; a negative argument may be used to move backward
				7716	through the list.
				7717	This command is intended to be bound to <B>TAB</B>, but is unbound
				7718	by default.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7719	<DT><B>menu-complete-backward</B>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	7720
				7721	<DD>
				7722	Identical to <B>menu-complete</B>, but moves backward through the list
				7723	of possible completions, as if <B>menu-complete</B> had been given a
				7724	negative argument. This command is unbound by default.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7725	<DT><B>delete-char-or-list</B>
				7726
				7727	<DD>
				7728	Deletes the character under the cursor if not at the beginning or
				7729	end of the line (like <B>delete-char</B>).
				7730	If at the end of the line, behaves identically to
				7731	<B>possible-completions</B>.
				7732	This command is unbound by default.
				7733	<DT><B>complete-filename (M-/)</B>
				7734
				7735	<DD>
				7736	Attempt filename completion on the text before point.
				7737	<DT><B>possible-filename-completions (C-x /)</B>
				7738
				7739	<DD>
				7740	List the possible completions of the text before point,
				7741	treating it as a filename.
				7742	<DT><B>complete-username (M-~)</B>
				7743
				7744	<DD>
				7745	Attempt completion on the text before point, treating
				7746	it as a username.
				7747	<DT><B>possible-username-completions (C-x ~)</B>
				7748
				7749	<DD>
				7750	List the possible completions of the text before point,
				7751	treating it as a username.
				7752	<DT><B>complete-variable (M-$)</B>
				7753
				7754	<DD>
				7755	Attempt completion on the text before point, treating
				7756	it as a shell variable.
				7757	<DT><B>possible-variable-completions (C-x $)</B>
				7758
				7759	<DD>
				7760	List the possible completions of the text before point,
				7761	treating it as a shell variable.
				7762	<DT><B>complete-hostname (M-@)</B>
				7763
				7764	<DD>
				7765	Attempt completion on the text before point, treating
				7766	it as a hostname.
				7767	<DT><B>possible-hostname-completions (C-x @)</B>
				7768
				7769	<DD>
				7770	List the possible completions of the text before point,
				7771	treating it as a hostname.
				7772	<DT><B>complete-command (M-!)</B>
				7773
				7774	<DD>
				7775	Attempt completion on the text before point, treating
				7776	it as a command name. Command completion attempts to
				7777	match the text against aliases, reserved words, shell
				7778	functions, shell builtins, and finally executable filenames,
				7779	in that order.
				7780	<DT><B>possible-command-completions (C-x !)</B>
				7781
				7782	<DD>
				7783	List the possible completions of the text before point,
				7784	treating it as a command name.
				7785	<DT><B>dynamic-complete-history (M-TAB)</B>
				7786
				7787	<DD>
				7788	Attempt completion on the text before point, comparing
				7789	the text against lines from the history list for possible
				7790	completion matches.
				7791	<DT><B>dabbrev-expand</B>
				7792
				7793	<DD>
				7794	Attempt menu completion on the text before point, comparing
				7795	the text against lines from the history list for possible
				7796	completion matches.
				7797	<DT><B>complete-into-braces (M-{)</B>
				7798
				7799	<DD>
				7800	Perform filename completion and insert the list of possible completions
				7801	enclosed within braces so the list is available to the shell (see
				7802	<B>Brace Expansion</B>
				7803
				7804	above).
				7805
				7806	</DL>
				7807	<A NAME="lbCT"> </A>
				7808	<H4>Keyboard Macros</H4>
				7809
				7810	<P>
				7811
				7812
				7813	<DL COMPACT>
				7814	<DT><B>start-kbd-macro (C-x ()</B>
				7815
				7816	<DD>
				7817	Begin saving the characters typed into the current keyboard macro.
				7818	<DT><B>end-kbd-macro (C-x ))</B>
				7819
				7820	<DD>
				7821	Stop saving the characters typed into the current keyboard macro
				7822	and store the definition.
				7823	<DT><B>call-last-kbd-macro (C-x e)</B>
				7824
				7825	<DD>
				7826	Re-execute the last keyboard macro defined, by making the characters
				7827	in the macro appear as if typed at the keyboard.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7828	<DT><B>print-last-kbd-macro ()</B>
				7829
				7830	<DD>
				7831	Print the last keyboard macro defined in a format suitable for the
				7832	<I>inputrc</I> file.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7833
				7834	</DL>
				7835	<A NAME="lbCU"> </A>
				7836	<H4>Miscellaneous</H4>
				7837
				7838	<P>
				7839
				7840
				7841	<DL COMPACT>
				7842	<DT><B>re-read-init-file (C-x C-r)</B>
				7843
				7844	<DD>
				7845	Read in the contents of the <I>inputrc</I> file, and incorporate
				7846	any bindings or variable assignments found there.
				7847	<DT><B>abort (C-g)</B>
				7848
				7849	<DD>
				7850	Abort the current editing command and
				7851	ring the terminal's bell (subject to the setting of
				7852	<B>bell-style</B>).
				7853
				7854	<DT><B>do-uppercase-version (M-a, M-b, M-</B><I>x</I>, ...)
				7855
				7856	<DD>
				7857	If the metafied character <I>x</I> is lowercase, run the command
				7858	that is bound to the corresponding uppercase character.
				7859	<DT><B>prefix-meta (ESC)</B>
				7860
				7861	<DD>
				7862	Metafy the next character typed.
				7863	<FONT SIZE=-1><B>ESC</B>
				7864
				7865	</FONT>
				7866	<B>f</B>
				7867
				7868	is equivalent to
				7869	<B>Meta-f</B>.
				7870
				7871	<DT><B>undo (C-_, C-x C-u)</B>
				7872
				7873	<DD>
				7874	Incremental undo, separately remembered for each line.
				7875	<DT><B>revert-line (M-r)</B>
				7876
				7877	<DD>
				7878	Undo all changes made to this line. This is like executing the
				7879	<B>undo</B>
				7880
				7881	command enough times to return the line to its initial state.
				7882	<DT><B>tilde-expand (M-&)</B>
				7883
				7884	<DD>
				7885	Perform tilde expansion on the current word.
				7886	<DT><B>set-mark (C-@, M-<space>)</B>
				7887
				7888	<DD>
				7889	Set the mark to the point. If a
				7890	numeric argument is supplied, the mark is set to that position.
				7891	<DT><B>exchange-point-and-mark (C-x C-x)</B>
				7892
				7893	<DD>
				7894	Swap the point with the mark. The current cursor position is set to
				7895	the saved position, and the old cursor position is saved as the mark.
				7896	<DT><B>character-search (C-])</B>
				7897
				7898	<DD>
				7899	A character is read and point is moved to the next occurrence of that
				7900	character. A negative count searches for previous occurrences.
				7901	<DT><B>character-search-backward (M-C-])</B>
				7902
				7903	<DD>
				7904	A character is read and point is moved to the previous occurrence of that
				7905	character. A negative count searches for subsequent occurrences.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	7906	<DT><B>skip-csi-sequence</B>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	7907
				7908	<DD>
				7909	Read enough characters to consume a multi-key sequence such as those
				7910	defined for keys like Home and End. Such sequences begin with a
				7911	Control Sequence Indicator (CSI), usually ESC-[. If this sequence is
				7912	bound to "\[", keys producing such sequences will have no effect
				7913	unless explicitly bound to a readline command, instead of inserting
				7914	stray characters into the editing buffer. This is unbound by default,
				7915	but usually bound to ESC-[.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7916	<DT><B>insert-comment (M-#)</B>
				7917
				7918	<DD>
				7919	Without a numeric argument, the value of the readline
				7920	<B>comment-begin</B>
				7921
				7922	variable is inserted at the beginning of the current line.
				7923	If a numeric argument is supplied, this command acts as a toggle: if
				7924	the characters at the beginning of the line do not match the value
				7925	of <B>comment-begin</B>, the value is inserted, otherwise
				7926	the characters in <B>comment-begin</B> are deleted from the beginning of
				7927	the line.
				7928	In either case, the line is accepted as if a newline had been typed.
				7929	The default value of
				7930	<B>comment-begin</B> causes this command to make the current line
				7931	a shell comment.
				7932	If a numeric argument causes the comment character to be removed, the line
				7933	will be executed by the shell.
				7934	<DT><B>glob-complete-word (M-g)</B>
				7935
				7936	<DD>
				7937	The word before point is treated as a pattern for pathname expansion,
				7938	with an asterisk implicitly appended. This pattern is used to
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7939	generate a list of matching filenames for possible completions.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7940	<DT><B>glob-expand-word (C-x *)</B>
				7941
				7942	<DD>
				7943	The word before point is treated as a pattern for pathname expansion,
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	7944	and the list of matching filenames is inserted, replacing the word.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	7945	If a numeric argument is supplied, an asterisk is appended before
				7946	pathname expansion.
				7947	<DT><B>glob-list-expansions (C-x g)</B>
				7948
				7949	<DD>
				7950	The list of expansions that would have been generated by
				7951	<B>glob-expand-word</B>
				7952
				7953	is displayed, and the line is redrawn.
				7954	If a numeric argument is supplied, an asterisk is appended before
				7955	pathname expansion.
				7956	<DT><B>dump-functions</B>
				7957
				7958	<DD>
				7959	Print all of the functions and their key bindings to the
				7960	readline output stream. If a numeric argument is supplied,
				7961	the output is formatted in such a way that it can be made part
				7962	of an <I>inputrc</I> file.
				7963	<DT><B>dump-variables</B>
				7964
				7965	<DD>
				7966	Print all of the settable readline variables and their values to the
				7967	readline output stream. If a numeric argument is supplied,
				7968	the output is formatted in such a way that it can be made part
				7969	of an <I>inputrc</I> file.
				7970	<DT><B>dump-macros</B>
				7971
				7972	<DD>
				7973	Print all of the readline key sequences bound to macros and the
				7974	strings they output. If a numeric argument is supplied,
				7975	the output is formatted in such a way that it can be made part
				7976	of an <I>inputrc</I> file.
				7977	<DT><B>display-shell-version (C-x C-v)</B>
				7978
				7979	<DD>
				7980	Display version information about the current instance of
				7981	<B>bash</B>.
				7982
				7983
				7984	</DL>
				7985	<A NAME="lbCV"> </A>
				7986	<H4>Programmable Completion</H4>
				7987
				7988	<P>
				7989
				7990	When word completion is attempted for an argument to a command for
				7991	which a completion specification (a <I>compspec</I>) has been defined
				7992	using the <B>complete</B> builtin (see
				7993	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				7994
				7995	</FONT>
				7996	below), the programmable completion facilities are invoked.
				7997	<P>
				7998
				7999	First, the command name is identified.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8000	If the command word is the empty string (completion attempted at the
				8001	beginning of an empty line), any compspec defined with
				8002	the <B>-E</B> option to <B>complete</B> is used.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8003	If a compspec has been defined for that command, the
				8004	compspec is used to generate the list of possible completions for the word.
				8005	If the command word is a full pathname, a compspec for the full
				8006	pathname is searched for first.
				8007	If no compspec is found for the full pathname, an attempt is made to
				8008	find a compspec for the portion following the final slash.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	8009	If those searches do not result in a compspec, any compspec defined with
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8010	the <B>-D</B> option to <B>complete</B> is used as the default.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8011	<P>
				8012
				8013	Once a compspec has been found, it is used to generate the list of
				8014	matching words.
				8015	If a compspec is not found, the default <B>bash</B> completion as
				8016	described above under <B>Completing</B> is performed.
				8017	<P>
				8018
				8019	First, the actions specified by the compspec are used.
				8020	Only matches which are prefixed by the word being completed are
				8021	returned.
				8022	When the
				8023	<B>-f</B>
				8024
				8025	or
				8026	<B>-d</B>
				8027
				8028	option is used for filename or directory name completion, the shell
				8029	variable
				8030	<FONT SIZE=-1><B>FIGNORE</B>
				8031
				8032	</FONT>
				8033	is used to filter the matches.
				8034	<P>
				8035
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8036	Any completions specified by a pathname expansion pattern to the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8037	<B>-G</B> option are generated next.
				8038	The words generated by the pattern need not match the word
				8039	being completed.
				8040	The
				8041	<FONT SIZE=-1><B>GLOBIGNORE</B>
				8042
				8043	</FONT>
				8044	shell variable is not used to filter the matches, but the
				8045	<FONT SIZE=-1><B>FIGNORE</B>
				8046
				8047	</FONT>
				8048	variable is used.
				8049	<P>
				8050
				8051	Next, the string specified as the argument to the <B>-W</B> option
				8052	is considered.
				8053	The string is first split using the characters in the
				8054	<FONT SIZE=-1><B>IFS</B>
				8055
				8056	</FONT>
				8057	special variable as delimiters.
				8058	Shell quoting is honored.
				8059	Each word is then expanded using
				8060	brace expansion, tilde expansion, parameter and variable expansion,
				8061	command substitution, and arithmetic expansion,
				8062	as described above under
				8063	<FONT SIZE=-1><B>EXPANSION</B>.
				8064
				8065	</FONT>
				8066	The results are split using the rules described above under
				8067	<B>Word Splitting</B>.
				8068	The results of the expansion are prefix-matched against the word being
				8069	completed, and the matching words become the possible completions.
				8070	<P>
				8071
				8072	After these matches have been generated, any shell function or command
				8073	specified with the <B>-F</B> and <B>-C</B> options is invoked.
				8074	When the command or function is invoked, the
				8075	<FONT SIZE=-1><B>COMP_LINE</B>,
				8076
				8077	</FONT>
				8078	<FONT SIZE=-1><B>COMP_POINT</B>,
				8079
				8080	</FONT>
				8081	<FONT SIZE=-1><B>COMP_KEY</B>,
				8082
				8083	</FONT>
				8084	and
				8085	<FONT SIZE=-1><B>COMP_TYPE</B>
				8086
				8087	</FONT>
				8088	variables are assigned values as described above under
				8089	<B>Shell Variables</B>.
				8090	If a shell function is being invoked, the
				8091	<FONT SIZE=-1><B>COMP_WORDS</B>
				8092
				8093	</FONT>
				8094	and
				8095	<FONT SIZE=-1><B>COMP_CWORD</B>
				8096
				8097	</FONT>
				8098	variables are also set.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8099	When the function or command is invoked,
				8100	the first argument (<B>$1</B>) is the name of the command whose arguments are
				8101	being completed,
				8102	the second argument (<B>$2</B>) is the word being completed,
				8103	and the third argument (<B>$3</B>) is the word preceding the word being
				8104	completed on the current command line.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8105	No filtering of the generated completions against the word being completed
				8106	is performed; the function or command has complete freedom in generating
				8107	the matches.
				8108	<P>
				8109
				8110	Any function specified with <B>-F</B> is invoked first.
				8111	The function may use any of the shell facilities, including the
				8112	<B>compgen</B> builtin described below, to generate the matches.
				8113	It must put the possible completions in the
				8114	<FONT SIZE=-1><B>COMPREPLY</B>
				8115
				8116	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8117	array variable, one per array element.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8118	<P>
				8119
				8120	Next, any command specified with the <B>-C</B> option is invoked
				8121	in an environment equivalent to command substitution.
				8122	It should print a list of completions, one per line, to the
				8123	standard output.
				8124	Backslash may be used to escape a newline, if necessary.
				8125	<P>
				8126
				8127	After all of the possible completions are generated, any filter
				8128	specified with the <B>-X</B> option is applied to the list.
				8129	The filter is a pattern as used for pathname expansion; a <B>&</B>
				8130	in the pattern is replaced with the text of the word being completed.
				8131	A literal <B>&</B> may be escaped with a backslash; the backslash
				8132	is removed before attempting a match.
				8133	Any completion that matches the pattern will be removed from the list.
				8134	A leading <B>!</B> negates the pattern; in this case any completion
				8135	not matching the pattern will be removed.
				8136	<P>
				8137
				8138	Finally, any prefix and suffix specified with the <B>-P</B> and <B>-S</B>
				8139	options are added to each member of the completion list, and the result is
				8140	returned to the readline completion code as the list of possible
				8141	completions.
				8142	<P>
				8143
				8144	If the previously-applied actions do not generate any matches, and the
				8145	<B>-o dirnames</B> option was supplied to <B>complete</B> when the
				8146	compspec was defined, directory name completion is attempted.
				8147	<P>
				8148
				8149	If the <B>-o plusdirs</B> option was supplied to <B>complete</B> when the
				8150	compspec was defined, directory name completion is attempted and any
				8151	matches are added to the results of the other actions.
				8152	<P>
				8153
				8154	By default, if a compspec is found, whatever it generates is returned
				8155	to the completion code as the full set of possible completions.
				8156	The default <B>bash</B> completions are not attempted, and the readline
				8157	default of filename completion is disabled.
				8158	If the <B>-o bashdefault</B> option was supplied to <B>complete</B> when
				8159	the compspec was defined, the <B>bash</B> default completions are attempted
				8160	if the compspec generates no matches.
				8161	If the <B>-o default</B> option was supplied to <B>complete</B> when the
				8162	compspec was defined, readline's default completion will be performed
				8163	if the compspec (and, if attempted, the default <B>bash</B> completions)
				8164	generate no matches.
				8165	<P>
				8166
				8167	When a compspec indicates that directory name completion is desired,
				8168	the programmable completion functions force readline to append a slash
				8169	to completed names which are symbolic links to directories, subject to
				8170	the value of the <B>mark-directories</B> readline variable, regardless
				8171	of the setting of the <B>mark-symlinked-directories</B> readline variable.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8172	<P>
				8173
				8174	There is some support for dynamically modifying completions. This is
				8175	most useful when used in combination with a default completion specified
				8176	with <B>complete -D</B>.
				8177	It's possible for shell functions executed as completion
				8178	handlers to indicate that completion should be retried by returning an
				8179	exit status of 124. If a shell function returns 124, and changes
				8180	the compspec associated with the command on which completion is being
				8181	attempted (supplied as the first argument when the function is executed),
				8182	programmable completion restarts from the beginning, with an
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	8183	attempt to find a new compspec for that command. This allows a set of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8184	completions to be built dynamically as completion is attempted, rather than
				8185	being loaded all at once.
				8186	<P>
				8187
				8188	For instance, assuming that there is a library of compspecs, each kept in a
				8189	file corresponding to the name of the command, the following default
				8190	completion function would load completions dynamically:
				8191	<P>
				8192
				8193	<TT>_completion_loader()
				8194	<BR>
				8195
				8196	{
				8197	<BR>
				8198
				8199	<TT>       </TT>. "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return 124<BR>
				8200	<BR>
				8201
				8202	}
				8203	<BR>
				8204
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8205	complete -D -F _completion_loader -o bashdefault -o default
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8206	<BR>
				8207
				8208	</TT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8209	<A NAME="lbCW"> </A>
				8210	<H3>HISTORY</H3>
				8211
				8212	When the
				8213	<B>-o history</B>
				8214
				8215	option to the
				8216	<B>set</B>
				8217
				8218	builtin is enabled, the shell provides access to the
				8219	<I>command history</I>,
				8220	the list of commands previously typed.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8221	The value of the
				8222	<FONT SIZE=-1><B>HISTSIZE</B>
				8223
				8224	</FONT>
				8225	variable is used as the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8226	number of commands to save in a history list.
				8227	The text of the last
				8228	<FONT SIZE=-1><B>HISTSIZE</B>
				8229
				8230	</FONT>
				8231	commands (default 500) is saved. The shell
				8232	stores each command in the history list prior to parameter and
				8233	variable expansion (see
				8234	<FONT SIZE=-1><B>EXPANSION</B>
				8235
				8236	</FONT>
				8237	above) but after history expansion is performed, subject to the
				8238	values of the shell variables
				8239	<FONT SIZE=-1><B>HISTIGNORE</B>
				8240
				8241	</FONT>
				8242	and
				8243	<FONT SIZE=-1><B>HISTCONTROL</B>.
				8244
				8245	</FONT>
				8246	<P>
				8247
				8248	On startup, the history is initialized from the file named by
				8249	the variable
				8250	<FONT SIZE=-1><B>HISTFILE</B>
				8251
				8252	</FONT>
				8253	(default <A HREF="file:~/.bash_history"><I>~/.bash_history</I></A>).
				8254	The file named by the value of
				8255	<FONT SIZE=-1><B>HISTFILE</B>
				8256
				8257	</FONT>
				8258	is truncated, if necessary, to contain no more than
				8259	the number of lines specified by the value of
				8260	<FONT SIZE=-1><B>HISTFILESIZE</B>.
				8261
				8262	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8263	If <B>HISTFILESIZE</B> is unset, or set to null, a non-numeric value,
				8264	or a numeric value less than zero, the history file is not truncated.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8265	When the history file is read,
				8266	lines beginning with the history comment character followed immediately
				8267	by a digit are interpreted as timestamps for the preceding history line.
				8268	These timestamps are optionally displayed depending on the value of the
				8269	<FONT SIZE=-1><B>HISTTIMEFORMAT</B>
				8270
				8271	</FONT>
				8272	variable.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8273	When a shell with history enabled exits, the last
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8274	<FONT SIZE=-1><B>$HISTSIZE</B>
				8275
				8276	</FONT>
				8277	lines are copied from the history list to
				8278	<FONT SIZE=-1><B>$HISTFILE</B>.
				8279
				8280	</FONT>
				8281	If the
				8282	<B>histappend</B>
				8283
				8284	shell option is enabled
				8285	(see the description of
				8286	<B>shopt</B>
				8287
				8288	under
				8289	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				8290
				8291	</FONT>
				8292	below), the lines are appended to the history file,
				8293	otherwise the history file is overwritten.
				8294	If
				8295	<FONT SIZE=-1><B>HISTFILE</B>
				8296
				8297	</FONT>
				8298	is unset, or if the history file is unwritable, the history is
				8299	not saved.
				8300	If the
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8301	<FONT SIZE=-1><B>HISTTIMEFORMAT</B>
				8302
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8303	</FONT>
				8304	variable is set, time stamps are written to the history file, marked
				8305	with the history comment character, so
				8306	they may be preserved across shell sessions.
				8307	This uses the history comment character to distinguish timestamps from
				8308	other history lines.
				8309	After saving the history, the history file is truncated
				8310	to contain no more than
				8311	<FONT SIZE=-1><B>HISTFILESIZE</B>
				8312
				8313	</FONT>
				8314	lines. If
				8315	<FONT SIZE=-1><B>HISTFILESIZE</B>
				8316
				8317	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8318	is unset, or set to null, a non-numeric value,
				8319	or a numeric value less than zero, the history file is not truncated.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8320	<P>
				8321
				8322	The builtin command
				8323	<B>fc</B>
				8324
				8325	(see
				8326	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				8327
				8328	</FONT>
				8329	below) may be used to list or edit and re-execute a portion of
				8330	the history list.
				8331	The
				8332	<B>history</B>
				8333
				8334	builtin may be used to display or modify the history list and
				8335	manipulate the history file.
				8336	When using command-line editing, search commands
				8337	are available in each editing mode that provide access to the
				8338	history list.
				8339	<P>
				8340
				8341	The shell allows control over which commands are saved on the history
				8342	list. The
				8343	<FONT SIZE=-1><B>HISTCONTROL</B>
				8344
				8345	</FONT>
				8346	and
				8347	<FONT SIZE=-1><B>HISTIGNORE</B>
				8348
				8349	</FONT>
				8350	variables may be set to cause the shell to save only a subset of the
				8351	commands entered.
				8352	The
				8353	<B>cmdhist</B>
				8354
				8355	shell option, if enabled, causes the shell to attempt to save each
				8356	line of a multi-line command in the same history entry, adding
				8357	semicolons where necessary to preserve syntactic correctness.
				8358	The
				8359	<B>lithist</B>
				8360
				8361	shell option causes the shell to save the command with embedded newlines
				8362	instead of semicolons. See the description of the
				8363	<B>shopt</B>
				8364
				8365	builtin below under
				8366	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				8367
				8368	</FONT>
				8369	for information on setting and unsetting shell options.
				8370	<A NAME="lbCX"> </A>
				8371	<H3>HISTORY EXPANSION</H3>
				8372
				8373	<P>
				8374
				8375	The shell supports a history expansion feature that
				8376	is similar to the history expansion in
				8377	<B>csh.</B>
				8378
				8379	This section describes what syntax features are available. This
				8380	feature is enabled by default for interactive shells, and can be
				8381	disabled using the
				8382	<B>+H</B>
				8383
				8384	option to the
				8385	<B>set</B>
				8386
				8387	builtin command (see
				8388	<FONT SIZE=-1><B>SHELL BUILTIN COMMANDS</B>
				8389
				8390	</FONT>
				8391	below). Non-interactive shells do not perform history expansion
				8392	by default.
				8393	<P>
				8394
				8395	History expansions introduce words from the history list into
				8396	the input stream, making it easy to repeat commands, insert the
				8397	arguments to a previous command into the current input line, or
				8398	fix errors in previous commands quickly.
				8399	<P>
				8400
				8401	History expansion is performed immediately after a complete line
				8402	is read, before the shell breaks it into words.
				8403	It takes place in two parts.
				8404	The first is to determine which line from the history list
				8405	to use during substitution.
				8406	The second is to select portions of that line for inclusion into
				8407	the current one.
				8408	The line selected from the history is the <I>event</I>,
				8409	and the portions of that line that are acted upon are <I>words</I>.
				8410	Various <I>modifiers</I> are available to manipulate the selected words.
				8411	The line is broken into words in the same fashion as when reading input,
				8412	so that several <I>metacharacter</I>-separated words surrounded by
				8413	quotes are considered one word.
				8414	History expansions are introduced by the appearance of the
				8415	history expansion character, which is <B>!</B> by default.
				8416	Only backslash (<B>\</B>) and single quotes can quote
				8417	the history expansion character.
				8418	<P>
				8419
				8420	Several characters inhibit history expansion if found immediately
				8421	following the history expansion character, even if it is unquoted:
				8422	space, tab, newline, carriage return, and <B>=</B>.
				8423	If the <B>extglob</B> shell option is enabled, <B>(</B> will also
				8424	inhibit expansion.
				8425	<P>
				8426
				8427	Several shell options settable with the
				8428	<B>shopt</B>
				8429
				8430	builtin may be used to tailor the behavior of history expansion.
				8431	If the
				8432	<B>histverify</B>
				8433
				8434	shell option is enabled (see the description of the
				8435	<B>shopt</B>
				8436
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8437	builtin below), and
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8438	<B>readline</B>
				8439
				8440	is being used, history substitutions are not immediately passed to
				8441	the shell parser.
				8442	Instead, the expanded line is reloaded into the
				8443	<B>readline</B>
				8444
				8445	editing buffer for further modification.
				8446	If
				8447	<B>readline</B>
				8448
				8449	is being used, and the
				8450	<B>histreedit</B>
				8451
				8452	shell option is enabled, a failed history substitution will be reloaded
				8453	into the
				8454	<B>readline</B>
				8455
				8456	editing buffer for correction.
				8457	The
				8458	<B>-p</B>
				8459
				8460	option to the
				8461	<B>history</B>
				8462
				8463	builtin command may be used to see what a history expansion will
				8464	do before using it.
				8465	The
				8466	<B>-s</B>
				8467
				8468	option to the
				8469	<B>history</B>
				8470
				8471	builtin may be used to add commands to the end of the history list
				8472	without actually executing them, so that they are available for
				8473	subsequent recall.
				8474	<P>
				8475
				8476	The shell allows control of the various characters used by the
				8477	history expansion mechanism (see the description of
				8478	<B>histchars</B>
				8479
				8480	above under
				8481	<B>Shell Variables</B>).
				8482
				8483	The shell uses
				8484	the history comment character to mark history timestamps when
				8485	writing the history file.
				8486	<A NAME="lbCY"> </A>
				8487	<H4>Event Designators</H4>
				8488
				8489	<P>
				8490
				8491	An event designator is a reference to a command line entry in the
				8492	history list.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	8493	Unless the reference is absolute, events are relative to the current
				8494	position in the history list.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8495	<P>
				8496
				8497
				8498	<DL COMPACT>
				8499	<DT><B>!</B>
				8500
				8501	<DD>
				8502	Start a history substitution, except when followed by a
				8503	<B>blank</B>,
				8504
				8505	newline, carriage return, =
				8506	or ( (when the <B>extglob</B> shell option is enabled using
				8507	the <B>shopt</B> builtin).
				8508	<DT><B>!</B><I>n</I>
				8509
				8510	<DD>
				8511	Refer to command line
				8512	<I>n</I>.
				8513
				8514	<DT><B>!-</B><I>n</I>
				8515
				8516	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	8517	Refer to the current command minus
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8518	<I>n</I>.
				8519
				8520	<DT><B>!!</B>
				8521
				8522	<DD>
				8523	Refer to the previous command. This is a synonym for `!-1'.
				8524	<DT><B>!</B><I>string</I>
				8525
				8526	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	8527	Refer to the most recent command preceding the current position in the
				8528	history list starting with
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8529	<I>string</I>.
				8530
				8531	<DT><B>!?</B><I>string</I><B>[?]</B>
				8532
				8533	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8534	Refer to the most recent command preceding the current position in the
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	8535	history list containing
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8536	<I>string</I>.
				8537
				8538	The trailing <B>?</B> may be omitted if
				8539	<I>string</I>
				8540
				8541	is followed immediately by a newline.
				8542	<DT><B></B><FONT SIZE=+2><B>^</B></FONT><B></B><I>string1</I><FONT SIZE=+2>^</FONT><I>string2</I><FONT SIZE=+2>^</FONT>
				8543
				8544	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	8545	Quick substitution. Repeat the previous command, replacing
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8546	<I>string1</I>
				8547
				8548	with
				8549	<I>string2</I>.
				8550
				8551	Equivalent to
				8552	``!!:s/<I>string1</I>/<I>string2</I>/''
				8553	(see <B>Modifiers</B> below).
				8554	<DT><B>!#</B>
				8555
				8556	<DD>
				8557	The entire command line typed so far.
				8558
				8559	</DL>
				8560	<A NAME="lbCZ"> </A>
				8561	<H4>Word Designators</H4>
				8562
				8563	<P>
				8564
				8565	Word designators are used to select desired words from the event.
				8566	A
				8567	<B>:</B>
				8568
				8569	separates the event specification from the word designator.
				8570	It may be omitted if the word designator begins with a
				8571	<B>^</B>,
				8572
				8573	<B>$</B>,
				8574
				8575	<B>*</B>,
				8576
				8577	<B>-</B>,
				8578
				8579	or
				8580	<B>%</B>.
				8581
				8582	Words are numbered from the beginning of the line,
				8583	with the first word being denoted by 0 (zero).
				8584	Words are inserted into the current line separated by single spaces.
				8585	<P>
				8586
				8587
				8588	<DL COMPACT>
				8589	<DT><B>0 (zero)</B>
				8590
				8591	<DD>
				8592	The zeroth word. For the shell, this is the command
				8593	word.
				8594	<DT><I>n</I>
				8595
				8596	<DD>
				8597	The <I>n</I>th word.
				8598	<DT><B>^</B>
				8599
				8600	<DD>
				8601	The first argument. That is, word 1.
				8602	<DT><B>$</B>
				8603
				8604	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8605	The last word. This is usually the last argument, but will expand to the
				8606	zeroth word if there is only one word in the line.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8607	<DT><B>%</B>
				8608
				8609	<DD>
				8610	The word matched by the most recent `?<I>string</I>?' search.
				8611	<DT><I>x</I><B>-</B>y
				8612
				8613	<DD>
				8614	A range of words; `-<I>y</I>' abbreviates `0-<I>y</I>'.
				8615	<DT><B>*</B>
				8616
				8617	<DD>
				8618	All of the words but the zeroth. This is a synonym
				8619	for `<I>1-$</I>'. It is not an error to use
				8620	<B>*</B>
				8621
				8622	if there is just one
				8623	word in the event; the empty string is returned in that case.
				8624	<DT><B>x*</B>
				8625
				8626	<DD>
				8627	Abbreviates <I>x-$</I>.
				8628	<DT><B>x-</B>
				8629
				8630	<DD>
				8631	Abbreviates <I>x-$</I> like <B>x*</B>, but omits the last word.
				8632
				8633	</DL>
				8634	<P>
				8635
				8636	If a word designator is supplied without an event specification, the
				8637	previous command is used as the event.
				8638	<A NAME="lbDA"> </A>
				8639	<H4>Modifiers</H4>
				8640
				8641	<P>
				8642
				8643	After the optional word designator, there may appear a sequence of
				8644	one or more of the following modifiers, each preceded by a `:'.
				8645	<P>
				8646
				8647
				8648	<P>
				8649
				8650	<DL COMPACT>
				8651	<DT><B>h</B>
				8652
				8653	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8654	Remove a trailing filename component, leaving only the head.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8655	<DT><B>t</B>
				8656
				8657	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8658	Remove all leading filename components, leaving the tail.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8659	<DT><B>r</B>
				8660
				8661	<DD>
				8662	Remove a trailing suffix of the form <I>.xxx</I>, leaving the
				8663	basename.
				8664	<DT><B>e</B>
				8665
				8666	<DD>
				8667	Remove all but the trailing suffix.
				8668	<DT><B>p</B>
				8669
				8670	<DD>
				8671	Print the new command but do not execute it.
				8672	<DT><B>q</B>
				8673
				8674	<DD>
				8675	Quote the substituted words, escaping further substitutions.
				8676	<DT><B>x</B>
				8677
				8678	<DD>
				8679	Quote the substituted words as with
				8680	<B>q</B>,
				8681
				8682	but break into words at
				8683	<B>blanks</B>
				8684
				8685	and newlines.
				8686	<DT><B>s/</B><I>old</I>/<I>new</I>/
				8687
				8688	<DD>
				8689	Substitute
				8690	<I>new</I>
				8691
				8692	for the first occurrence of
				8693	<I>old</I>
				8694
				8695	in the event line. Any delimiter can be used in place of /. The
				8696	final delimiter is optional if it is the last character of the
				8697	event line. The delimiter may be quoted in
				8698	<I>old</I>
				8699
				8700	and
				8701	<I>new</I>
				8702
				8703	with a single backslash. If & appears in
				8704	<I>new</I>,
				8705
				8706	it is replaced by
				8707	<I>old</I>.
				8708
				8709	A single backslash will quote the &. If
				8710	<I>old</I>
				8711
				8712	is null, it is set to the last
				8713	<I>old</I>
				8714
				8715	substituted, or, if no previous history substitutions took place,
				8716	the last
				8717	<I>string</I>
				8718
				8719	in a
				8720	<B>!?</B><I>string</I><B>[?]</B>
				8721
				8722	search.
				8723	<DT><B>&</B>
				8724
				8725	<DD>
				8726	Repeat the previous substitution.
				8727	<DT><B>g</B>
				8728
				8729	<DD>
				8730	Cause changes to be applied over the entire event line. This is
				8731	used in conjunction with `<B>:s</B>' (e.g., `<B>:gs/</B><I>old</I>/<I>new</I>/')
				8732	or `<B>:&</B>'. If used with
				8733	`<B>:s</B>', any delimiter can be used
				8734	in place of /, and the final delimiter is optional
				8735	if it is the last character of the event line.
				8736	An <B>a</B> may be used as a synonym for <B>g</B>.
				8737	<DT><B>G</B>
				8738
				8739	<DD>
				8740	Apply the following `<B>s</B>' modifier once to each word in the event line.
				8741
				8742	</DL>
				8743	<A NAME="lbDB"> </A>
				8744	<H3>SHELL BUILTIN COMMANDS</H3>
				8745
				8746
				8747
				8748	<P>
				8749
				8750	Unless otherwise noted, each builtin command documented in this
				8751	section as accepting options preceded by
				8752	<B>-</B>
				8753
				8754	accepts
				8755	<B>--</B>
				8756
				8757	to signify the end of the options.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8758	The <B>:</B>, <B>true</B>, <B>false</B>, and <B>test</B> builtins
				8759	do not accept options and do not treat <B>--</B> specially.
				8760	The <B>exit</B>, <B>logout</B>, <B>break</B>, <B>continue</B>, <B>let</B>,
				8761	and <B>shift</B> builtins accept and process arguments beginning with
				8762	<B>-</B> without requiring <B>--</B>.
				8763	Other builtins that accept arguments but are not specified as accepting
				8764	options interpret arguments beginning with <B>-</B> as invalid options and
				8765	require <B>--</B> to prevent this interpretation.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8766	<P>
				8767
				8768	<DL COMPACT>
				8769	<DT><B>:</B> [<I>arguments</I>]<DD>
				8770
				8771	No effect; the command does nothing beyond expanding
				8772	<I>arguments</I>
				8773
				8774	and performing any specified
				8775	redirections. A zero exit code is returned.
				8776	<DT><B> . </B> <I>filename</I> [<I>arguments</I>]<DD>
				8777
				8778	<DT><B>source</B> <I>filename</I> [<I>arguments</I>]<DD>
				8779
				8780	Read and execute commands from
				8781	<I>filename</I>
				8782
				8783	in the current
				8784	shell environment and return the exit status of the last command
				8785	executed from
				8786	<I>filename</I>.
				8787
				8788	If
				8789	<I>filename</I>
				8790
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8791	does not contain a slash, filenames in
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8792	<FONT SIZE=-1><B>PATH</B>
				8793
				8794	</FONT>
				8795	are used to find the directory containing
				8796	<I>filename</I>.
				8797
				8798	The file searched for in
				8799	<FONT SIZE=-1><B>PATH</B>
				8800
				8801	</FONT>
				8802	need not be executable.
				8803	When <B>bash</B> is not in <I>posix mode</I>, the current directory is
				8804	searched if no file is found in
				8805	<FONT SIZE=-1><B>PATH</B>.
				8806
				8807	</FONT>
				8808	If the
				8809	<B>sourcepath</B>
				8810
				8811	option to the
				8812	<B>shopt</B>
				8813
				8814	builtin command is turned off, the
				8815	<FONT SIZE=-1><B>PATH</B>
				8816
				8817	</FONT>
				8818	is not searched.
				8819	If any <I>arguments</I> are supplied, they become the positional
				8820	parameters when <I>filename</I> is executed. Otherwise the positional
				8821	parameters are unchanged.
				8822	The return status is the status of the last command exited within
				8823	the script (0 if no commands are executed), and false if
				8824	<I>filename</I>
				8825
				8826	is not found or cannot be read.
				8827	<DT><B>alias</B> [<B>-p</B>] [<I>name</I>[=<I>value</I>] ...]<DD>
				8828	<B>Alias</B> with no arguments or with the
				8829	<B>-p</B>
				8830
				8831	option prints the list of aliases in the form
				8832	<B>alias</B> <I>name</I>=<I>value</I> on standard output.
				8833	When arguments are supplied, an alias is defined for
				8834	each <I>name</I> whose <I>value</I> is given.
				8835	A trailing space in <I>value</I> causes the next word to be
				8836	checked for alias substitution when the alias is expanded.
				8837	For each <I>name</I> in the argument list for which no <I>value</I>
				8838	is supplied, the name and value of the alias is printed.
				8839	<B>Alias</B> returns true unless a <I>name</I> is given for which
				8840	no alias has been defined.
				8841	<DT><B>bg</B> [<I>jobspec</I> ...]<DD>
				8842	Resume each suspended job <I>jobspec</I> in the background, as if it
				8843	had been started with
				8844	<B>&</B>.
				8845
				8846	If
				8847	<I>jobspec</I>
				8848
				8849	is not present, the shell's notion of the <I>current job</I> is used.
				8850	<B>bg</B>
				8851
				8852	<I>jobspec</I>
				8853
				8854	returns 0 unless run when job control is disabled or, when run with
				8855	job control enabled, any specified <I>jobspec</I> was not found
				8856	or was started without job control.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8857	<DT><B>bind</B> [<B>-m</B> <I>keymap</I>] [<B>-lpsvPSVX</B>]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8858
				8859	<DT><B>bind</B> [<B>-m</B> <I>keymap</I>] [<B>-q</B> <I>function</I>] [<B>-u</B> <I>function</I>] [<B>-r</B> <I>keyseq</I>]<DD>
				8860	<DT><B>bind</B> [<B>-m</B> <I>keymap</I>] <B>-f</B> <I>filename</I><DD>
				8861	<DT><B>bind</B> [<B>-m</B> <I>keymap</I>] <B>-x</B> <I>keyseq</I>:<I>shell-command</I><DD>
				8862	<DT><B>bind</B> [<B>-m</B> <I>keymap</I>] <I>keyseq</I>:<I>function-name</I><DD>
				8863	<DT><B>bind</B> <I>readline-command</I><DD>
				8864
				8865	Display current
				8866	<B>readline</B>
				8867
				8868	key and function bindings, bind a key sequence to a
				8869	<B>readline</B>
				8870
				8871	function or macro, or set a
				8872	<B>readline</B>
				8873
				8874	variable.
				8875	Each non-option argument is a command as it would appear in
				8876	<I>.inputrc</I>,
				8877
				8878	but each binding or command must be passed as a separate argument;
				8879	e.g., '"\C-x\C-r": re-read-init-file'.
				8880	Options, if supplied, have the following meanings:
				8881	<DL COMPACT><DT><DD>
				8882
				8883	<DL COMPACT>
				8884	<DT><B>-m </B><I>keymap</I>
				8885
				8886	<DD>
				8887	Use
				8888	<I>keymap</I>
				8889
				8890	as the keymap to be affected by the subsequent bindings.
				8891	Acceptable
				8892	<I>keymap</I>
				8893
				8894	names are
				8895	<I>emacs, emacs-standard, emacs-meta, emacs-ctlx, vi,
				8896	vi-move, vi-command</I>, and
				8897	<I>vi-insert</I>.
				8898
				8899	<I>vi</I> is equivalent to <I>vi-command</I>; <I>emacs</I> is
				8900	equivalent to <I>emacs-standard</I>.
				8901	<DT><B>-l</B>
				8902
				8903	<DD>
				8904	List the names of all <B>readline</B> functions.
				8905	<DT><B>-p</B>
				8906
				8907	<DD>
				8908	Display <B>readline</B> function names and bindings in such a way
				8909	that they can be re-read.
				8910	<DT><B>-P</B>
				8911
				8912	<DD>
				8913	List current <B>readline</B> function names and bindings.
				8914	<DT><B>-s</B>
				8915
				8916	<DD>
				8917	Display <B>readline</B> key sequences bound to macros and the strings
				8918	they output in such a way that they can be re-read.
				8919	<DT><B>-S</B>
				8920
				8921	<DD>
				8922	Display <B>readline</B> key sequences bound to macros and the strings
				8923	they output.
				8924	<DT><B>-v</B>
				8925
				8926	<DD>
				8927	Display <B>readline</B> variable names and values in such a way that they
				8928	can be re-read.
				8929	<DT><B>-V</B>
				8930
				8931	<DD>
				8932	List current <B>readline</B> variable names and values.
				8933	<DT><B>-f </B><I>filename</I>
				8934
				8935	<DD>
				8936	Read key bindings from <I>filename</I>.
				8937	<DT><B>-q </B><I>function</I>
				8938
				8939	<DD>
				8940	Query about which keys invoke the named <I>function</I>.
				8941	<DT><B>-u </B><I>function</I>
				8942
				8943	<DD>
				8944	Unbind all keys bound to the named <I>function</I>.
				8945	<DT><B>-r </B><I>keyseq</I>
				8946
				8947	<DD>
				8948	Remove any current binding for <I>keyseq</I>.
				8949	<DT><B>-x </B><I>keyseq</I>:<I>shell-command</I>
				8950
				8951	<DD>
				8952	Cause <I>shell-command</I> to be executed whenever <I>keyseq</I> is
				8953	entered.
				8954	When <I>shell-command</I> is executed, the shell sets the
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8955	<FONT SIZE=-1><B>READLINE_LINE</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8956
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8957	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8958	variable to the contents of the <B>readline</B> line buffer and the
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8959	<FONT SIZE=-1><B>READLINE_POINT</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8960
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8961	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8962	variable to the current location of the insertion point.
				8963	If the executed command changes the value of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8964	<FONT SIZE=-1><B>READLINE_LINE</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8965
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8966	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8967	or
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8968	<FONT SIZE=-1><B>READLINE_POINT</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8969
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	8970	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8971	those new values will be reflected in the editing state.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	8972	<DT><B>-X</B>
				8973
				8974	<DD>
				8975	List all key sequences bound to shell commands and the associated commands
				8976	in a format that can be reused as input.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	8977
				8978	</DL>
				8979	<P>
				8980
				8981	The return value is 0 unless an unrecognized option is given or an
				8982	error occurred.
				8983	</DL>
				8984
				8985	<DT><B>break</B> [<I>n</I>]<DD>
				8986	Exit from within a
				8987	<B>for</B>,
				8988
				8989	<B>while</B>,
				8990
				8991	<B>until</B>,
				8992
				8993	or
				8994	<B>select</B>
				8995
				8996	loop. If <I>n</I> is specified, break <I>n</I> levels.
				8997	<I>n</I>
				8998
				8999	must be >= 1. If
				9000	<I>n</I>
				9001
				9002	is greater than the number of enclosing loops, all enclosing loops
				9003	are exited.
				9004	The return value is 0 unless <I>n</I> is not greater than or equal to 1.
				9005	<DT><B>builtin</B> <I>shell-builtin</I> [<I>arguments</I>]<DD>
				9006	Execute the specified shell builtin, passing it
				9007	<I>arguments</I>,
				9008
				9009	and return its exit status.
				9010	This is useful when defining a
				9011	function whose name is the same as a shell builtin,
				9012	retaining the functionality of the builtin within the function.
				9013	The <B>cd</B> builtin is commonly redefined this way.
				9014	The return status is false if
				9015	<I>shell-builtin</I>
				9016
				9017	is not a shell builtin command.
				9018	<DT><B>caller</B> [<I>expr</I>]<DD>
				9019	Returns the context of any active subroutine call (a shell function or
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9020	a script executed with the <B>.</B> or <B>source</B> builtins).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9021	Without <I>expr</I>, <B>caller</B> displays the line number and source
				9022	filename of the current subroutine call.
				9023	If a non-negative integer is supplied as <I>expr</I>, <B>caller</B>
				9024	displays the line number, subroutine name, and source file corresponding
				9025	to that position in the current execution call stack. This extra
				9026	information may be used, for example, to print a stack trace. The
				9027	current frame is frame 0.
				9028	The return value is 0 unless the shell is not executing a subroutine
				9029	call or <I>expr</I> does not correspond to a valid position in the
				9030	call stack.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9031	<DT><B>cd</B> [<B>-L</B>\|[<B>-P</B> [<B>-e</B>]] [-@]] [<I>dir</I>]<DD>
				9032	Change the current directory to <I>dir</I>.
				9033	if <I>dir</I> is not supplied, the value of the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9034	<FONT SIZE=-1><B>HOME</B>
				9035
				9036	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9037	shell variable is the default.
				9038	Any additional arguments following <I>dir</I> are ignored.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9039	The variable
				9040	<FONT SIZE=-1><B>CDPATH</B>
				9041
				9042	</FONT>
				9043	defines the search path for the directory containing
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9044	<I>dir</I>:
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9045
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9046	each directory name in
				9047	<FONT SIZE=-1><B>CDPATH</B>
				9048
				9049	</FONT>
				9050	is searched for <I>dir</I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9051	Alternative directory names in
				9052	<FONT SIZE=-1><B>CDPATH</B>
				9053
				9054	</FONT>
				9055	are separated by a colon (:). A null directory name in
				9056	<FONT SIZE=-1><B>CDPATH</B>
				9057
				9058	</FONT>
				9059	is the same as the current directory, i.e., ``<B>.</B>''. If
				9060	<I>dir</I>
				9061
				9062	begins with a slash (/),
				9063	then
				9064	<FONT SIZE=-1><B>CDPATH</B>
				9065
				9066	</FONT>
				9067	is not used. The
				9068	<B>-P</B>
				9069
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9070	option causes <B>cd</B> to use the physical directory structure
				9071	by resolving symbolic links while traversing <I>dir</I> and
				9072	before processing instances of <I>..</I> in <I>dir</I> (see also the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9073	<B>-P</B>
				9074
				9075	option to the
				9076	<B>set</B>
				9077
				9078	builtin command); the
				9079	<B>-L</B>
				9080
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9081	option forces symbolic links to be followed by resolving the link
				9082	after processing instances of <I>..</I> in <I>dir</I>.
				9083	If <I>..</I> appears in <I>dir</I>, it is processed by removing the
				9084	immediately previous pathname component from <I>dir</I>, back to a slash
				9085	or the beginning of <I>dir</I>.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9086	If the
				9087	<B>-e</B>
				9088
				9089	option is supplied with
				9090	<B>-P</B>,
				9091
				9092	and the current working directory cannot be successfully determined
				9093	after a successful directory change, <B>cd</B> will return an unsuccessful
				9094	status.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9095	On systems that support it, the <B>-@</B> option presents the extended
				9096	attributes associated with a file as a directory.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9097	An argument of
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9098	<B>-</B>
				9099
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9100	is converted to
				9101	<FONT SIZE=-1><B>$OLDPWD</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9102
				9103	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9104	before the directory change is attempted.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9105	If a non-empty directory name from
				9106	<FONT SIZE=-1><B>CDPATH</B>
				9107
				9108	</FONT>
				9109	is used, or if
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9110	<B>-</B> is the first argument, and the directory change is
				9111	successful, the absolute pathname of the new working directory is
				9112	written to the standard output.
				9113	The return value is true if the directory was successfully changed;
				9114	false otherwise.
				9115	<DT><B>command</B> [<B>-pVv</B>] <I>command</I> [<I>arg</I> ...]<DD>
				9116	Run
				9117	<I>command</I>
				9118
				9119	with
				9120	<I>args</I>
				9121
				9122	suppressing the normal shell function lookup. Only builtin
				9123	commands or commands found in the
				9124	<FONT SIZE=-1><B>PATH</B>
				9125
				9126	</FONT>
				9127	are executed. If the
				9128	<B>-p</B>
				9129
				9130	option is given, the search for
				9131	<I>command</I>
				9132
				9133	is performed using a default value for
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9134	<FONT SIZE=-1><B>PATH</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9135
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9136	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9137	that is guaranteed to find all of the standard utilities.
				9138	If either the
				9139	<B>-V</B>
				9140
				9141	or
				9142	<B>-v</B>
				9143
				9144	option is supplied, a description of
				9145	<I>command</I>
				9146
				9147	is printed. The
				9148	<B>-v</B>
				9149
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9150	option causes a single word indicating the command or filename
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9151	used to invoke
				9152	<I>command</I>
				9153
				9154	to be displayed; the
				9155	<B>-V</B>
				9156
				9157	option produces a more verbose description.
				9158	If the
				9159	<B>-V</B>
				9160
				9161	or
				9162	<B>-v</B>
				9163
				9164	option is supplied, the exit status is 0 if
				9165	<I>command</I>
				9166
				9167	was found, and 1 if not. If neither option is supplied and
				9168	an error occurred or
				9169	<I>command</I>
				9170
				9171	cannot be found, the exit status is 127. Otherwise, the exit status of the
				9172	<B>command</B>
				9173
				9174	builtin is the exit status of
				9175	<I>command</I>.
				9176
				9177	<DT><B>compgen</B> [<I>option</I>] [<I>word</I>]<DD>
				9178	Generate possible completion matches for <I>word</I> according to
				9179	the <I>option</I>s, which may be any option accepted by the
				9180	<B>complete</B>
				9181
				9182	builtin with the exception of <B>-p</B> and <B>-r</B>, and write
				9183	the matches to the standard output.
				9184	When using the <B>-F</B> or <B>-C</B> options, the various shell variables
				9185	set by the programmable completion facilities, while available, will not
				9186	have useful values.
				9187	<P>
				9188	The matches will be generated in the same way as if the programmable
				9189	completion code had generated them directly from a completion specification
				9190	with the same flags.
				9191	If <I>word</I> is specified, only those completions matching <I>word</I>
				9192	will be displayed.
				9193	<P>
				9194	The return value is true unless an invalid option is supplied, or no
				9195	matches were generated.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9196	<DT><B>complete</B> [<B>-abcdefgjksuv</B>] [<B>-o</B> <I>comp-option</I>] [<B>-DE</B>] [<B>-A</B> <I>action</I>] [<B>-G</B> <I>globpat</I>] [<B>-W</B> <I>wordlist</I>] [<B>-F</B> <I>function</I>] [<B>-C</B> <I>command</I>]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9197	<BR>
				9198
				9199	[<B>-X</B> <I>filterpat</I>] [<B>-P</B> <I>prefix</I>] [<B>-S</B> <I>suffix</I>] <I>name</I> [<I>name ...</I>]
				9200
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9201	<DT><B>complete</B> <B>-pr</B> [<B>-DE</B>] [<I>name</I> ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9202
				9203	Specify how arguments to each <I>name</I> should be completed.
				9204	If the <B>-p</B> option is supplied, or if no options are supplied,
				9205	existing completion specifications are printed in a way that allows
				9206	them to be reused as input.
				9207	The <B>-r</B> option removes a completion specification for
				9208	each <I>name</I>, or, if no <I>name</I>s are supplied, all
				9209	completion specifications.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9210	The <B>-D</B> option indicates that the remaining options and actions should
				9211	apply to the ``default'' command completion; that is, completion attempted
				9212	on a command for which no completion has previously been defined.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9213	The <B>-E</B> option indicates that the remaining options and actions should
				9214	apply to ``empty'' command completion; that is, completion attempted on a
				9215	blank line.
				9216	<P>
				9217	The process of applying these completion specifications when word completion
				9218	is attempted is described above under <B>Programmable Completion</B>.
				9219	<P>
				9220	Other options, if specified, have the following meanings.
				9221	The arguments to the <B>-G</B>, <B>-W</B>, and <B>-X</B> options
				9222	(and, if necessary, the <B>-P</B> and <B>-S</B> options)
				9223	should be quoted to protect them from expansion before the
				9224	<B>complete</B>
				9225
				9226	builtin is invoked.
				9227	<DL COMPACT><DT><DD>
				9228
				9229	<DL COMPACT>
				9230	<DT><B>-o</B> <I>comp-option</I><DD>
				9231	The <I>comp-option</I> controls several aspects of the compspec's behavior
				9232	beyond the simple generation of completions.
				9233	<I>comp-option</I> may be one of:
				9234	<DL COMPACT><DT><DD>
				9235	<DL COMPACT>
				9236	<DT><B>bashdefault</B>
				9237
				9238	<DD>
				9239	Perform the rest of the default <B>bash</B> completions if the compspec
				9240	generates no matches.
				9241	<DT><B>default</B>
				9242
				9243	<DD>
				9244	Use readline's default filename completion if the compspec generates
				9245	no matches.
				9246	<DT><B>dirnames</B>
				9247
				9248	<DD>
				9249	Perform directory name completion if the compspec generates no matches.
				9250	<DT><B>filenames</B>
				9251
				9252	<DD>
				9253	Tell readline that the compspec generates filenames, so it can perform any
				9254	filename-specific processing (like adding a slash to directory names,
				9255	quoting special characters, or suppressing trailing spaces).
				9256	Intended to be used with shell functions.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9257	<DT><B>noquote</B>
				9258
				9259	<DD>
				9260	Tell readline not to quote the completed words if they are filenames
				9261	(quoting filenames is the default).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9262	<DT><B>nospace</B>
				9263
				9264	<DD>
				9265	Tell readline not to append a space (the default) to words completed at
				9266	the end of the line.
				9267	<DT><B>plusdirs</B>
				9268
				9269	<DD>
				9270	After any matches defined by the compspec are generated,
				9271	directory name completion is attempted and any
				9272	matches are added to the results of the other actions.
				9273	</DL></DL>
				9274
				9275	<DT><B>-A</B> <I>action</I><DD>
				9276	The <I>action</I> may be one of the following to generate a list of possible
				9277	completions:
				9278	<DL COMPACT><DT><DD>
				9279	<DL COMPACT>
				9280	<DT><B>alias</B>
				9281
				9282	<DD>
				9283	Alias names. May also be specified as <B>-a</B>.
				9284	<DT><B>arrayvar</B>
				9285
				9286	<DD>
				9287	Array variable names.
				9288	<DT><B>binding</B>
				9289
				9290	<DD>
				9291	<B>Readline</B> key binding names.
				9292	<DT><B>builtin</B>
				9293
				9294	<DD>
				9295	Names of shell builtin commands. May also be specified as <B>-b</B>.
				9296	<DT><B>command</B>
				9297
				9298	<DD>
				9299	Command names. May also be specified as <B>-c</B>.
				9300	<DT><B>directory</B>
				9301
				9302	<DD>
				9303	Directory names. May also be specified as <B>-d</B>.
				9304	<DT><B>disabled</B>
				9305
				9306	<DD>
				9307	Names of disabled shell builtins.
				9308	<DT><B>enabled</B>
				9309
				9310	<DD>
				9311	Names of enabled shell builtins.
				9312	<DT><B>export</B>
				9313
				9314	<DD>
				9315	Names of exported shell variables. May also be specified as <B>-e</B>.
				9316	<DT><B>file</B>
				9317
				9318	<DD>
				9319	File names. May also be specified as <B>-f</B>.
				9320	<DT><B>function</B>
				9321
				9322	<DD>
				9323	Names of shell functions.
				9324	<DT><B>group</B>
				9325
				9326	<DD>
				9327	Group names. May also be specified as <B>-g</B>.
				9328	<DT><B>helptopic</B>
				9329
				9330	<DD>
				9331	Help topics as accepted by the <B>help</B> builtin.
				9332	<DT><B>hostname</B>
				9333
				9334	<DD>
				9335	Hostnames, as taken from the file specified by the
				9336	<FONT SIZE=-1><B>HOSTFILE</B>
				9337
				9338	</FONT>
				9339	shell variable.
				9340	<DT><B>job</B>
				9341
				9342	<DD>
				9343	Job names, if job control is active. May also be specified as <B>-j</B>.
				9344	<DT><B>keyword</B>
				9345
				9346	<DD>
				9347	Shell reserved words. May also be specified as <B>-k</B>.
				9348	<DT><B>running</B>
				9349
				9350	<DD>
				9351	Names of running jobs, if job control is active.
				9352	<DT><B>service</B>
				9353
				9354	<DD>
				9355	Service names. May also be specified as <B>-s</B>.
				9356	<DT><B>setopt</B>
				9357
				9358	<DD>
				9359	Valid arguments for the <B>-o</B> option to the <B>set</B> builtin.
				9360	<DT><B>shopt</B>
				9361
				9362	<DD>
				9363	Shell option names as accepted by the <B>shopt</B> builtin.
				9364	<DT><B>signal</B>
				9365
				9366	<DD>
				9367	Signal names.
				9368	<DT><B>stopped</B>
				9369
				9370	<DD>
				9371	Names of stopped jobs, if job control is active.
				9372	<DT><B>user</B>
				9373
				9374	<DD>
				9375	User names. May also be specified as <B>-u</B>.
				9376	<DT><B>variable</B>
				9377
				9378	<DD>
				9379	Names of all shell variables. May also be specified as <B>-v</B>.
				9380	</DL></DL>
				9381
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9382	<DT><B>-C</B> <I>command</I><DD>
				9383	<I>command</I> is executed in a subshell environment, and its output is
				9384	used as the possible completions.
				9385	<DT><B>-F</B> <I>function</I><DD>
				9386	The shell function <I>function</I> is executed in the current shell
				9387	environment.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9388	When the function is executed,
				9389	the first argument (<B>$1</B>) is the name of the command whose arguments are
				9390	being completed,
				9391	the second argument (<B>$2</B>) is the word being completed,
				9392	and the third argument (<B>$3</B>) is the word preceding the word being
				9393	completed on the current command line.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9394	When it finishes, the possible completions are retrieved from the value
				9395	of the
				9396	<FONT SIZE=-1><B>COMPREPLY</B>
				9397
				9398	</FONT>
				9399	array variable.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9400	<DT><B>-G</B> <I>globpat</I><DD>
				9401	The pathname expansion pattern <I>globpat</I> is expanded to generate
				9402	the possible completions.
				9403	<DT><B>-P</B> <I>prefix</I><DD>
				9404	<I>prefix</I> is added at the beginning of each possible completion
				9405	after all other options have been applied.
				9406	<DT><B>-S</B> <I>suffix</I><DD>
				9407	<I>suffix</I> is appended to each possible completion
				9408	after all other options have been applied.
				9409	<DT><B>-W</B> <I>wordlist</I><DD>
				9410	The <I>wordlist</I> is split using the characters in the
				9411	<FONT SIZE=-1><B>IFS</B>
				9412
				9413	</FONT>
				9414	special variable as delimiters, and each resultant word is expanded.
				9415	The possible completions are the members of the resultant list which
				9416	match the word being completed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9417	<DT><B>-X</B> <I>filterpat</I><DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9418	<I>filterpat</I> is a pattern as used for pathname expansion.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9419	It is applied to the list of possible completions generated by the
				9420	preceding options and arguments, and each completion matching
				9421	<I>filterpat</I> is removed from the list.
				9422	A leading <B>!</B> in <I>filterpat</I> negates the pattern; in this
				9423	case, any completion not matching <I>filterpat</I> is removed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9424
				9425	</DL>
				9426	<P>
				9427
				9428	The return value is true unless an invalid option is supplied, an option
				9429	other than <B>-p</B> or <B>-r</B> is supplied without a <I>name</I>
				9430	argument, an attempt is made to remove a completion specification for
				9431	a <I>name</I> for which no specification exists, or
				9432	an error occurs adding a completion specification.
				9433	</DL>
				9434
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9435	<DT><B>compopt</B> [<B>-o</B> <I>option</I>] [<B>-DE</B>] [<B>+o</B> <I>option</I>] [<I>name</I>]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9436	Modify completion options for each <I>name</I> according to the
				9437	<I>option</I>s, or for the
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9438	currently-executing completion if no <I>name</I>s are supplied.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9439	If no <I>option</I>s are given, display the completion options for each
				9440	<I>name</I> or the current completion.
				9441	The possible values of <I>option</I> are those valid for the <B>complete</B>
				9442	builtin described above.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9443	The <B>-D</B> option indicates that the remaining options should
				9444	apply to the ``default'' command completion; that is, completion attempted
				9445	on a command for which no completion has previously been defined.
				9446	The <B>-E</B> option indicates that the remaining options should
				9447	apply to ``empty'' command completion; that is, completion attempted on a
				9448	blank line.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9449	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9450	The return value is true unless an invalid option is supplied, an attempt
				9451	is made to modify the options for a <I>name</I> for which no completion
				9452	specification exists, or an output error occurs.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9453	<DT><B>continue</B> [<I>n</I>]<DD>
				9454	Resume the next iteration of the enclosing
				9455	<B>for</B>,
				9456
				9457	<B>while</B>,
				9458
				9459	<B>until</B>,
				9460
				9461	or
				9462	<B>select</B>
				9463
				9464	loop.
				9465	If
				9466	<I>n</I>
				9467
				9468	is specified, resume at the <I>n</I>th enclosing loop.
				9469	<I>n</I>
				9470
				9471	must be >= 1. If
				9472	<I>n</I>
				9473
				9474	is greater than the number of enclosing loops, the last enclosing loop
				9475	(the ``top-level'' loop) is resumed.
				9476	The return value is 0 unless <I>n</I> is not greater than or equal to 1.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9477	<DT><B>declare</B> [<B>-aAfFgilnrtux</B>] [<B>-p</B>] [<I>name</I>[=<I>value</I>] ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9478
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9479	<DT><B>typeset</B> [<B>-aAfFgilnrtux</B>] [<B>-p</B>] [<I>name</I>[=<I>value</I>] ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9480
				9481	Declare variables and/or give them attributes.
				9482	If no <I>name</I>s are given then display the values of variables.
				9483	The
				9484	<B>-p</B>
				9485
				9486	option will display the attributes and values of each
				9487	<I>name</I>.
				9488
				9489	When
				9490	<B>-p</B>
				9491
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9492	is used with <I>name</I> arguments, additional options,
				9493	other than <B>-f</B> and <B>-F</B>, are ignored.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9494	When
				9495	<B>-p</B>
				9496
				9497	is supplied without <I>name</I> arguments, it will display the attributes
				9498	and values of all variables having the attributes specified by the
				9499	additional options.
				9500	If no other options are supplied with <B>-p</B>, <B>declare</B> will display
				9501	the attributes and values of all shell variables. The <B>-f</B> option
				9502	will restrict the display to shell functions.
				9503	The
				9504	<B>-F</B>
				9505
				9506	option inhibits the display of function definitions; only the
				9507	function name and attributes are printed.
				9508	If the <B>extdebug</B> shell option is enabled using <B>shopt</B>,
				9509	the source file name and line number where the function is defined
				9510	are displayed as well. The
				9511	<B>-F</B>
				9512
				9513	option implies
				9514	<B>-f</B>.
				9515
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9516	The
				9517	<B>-g</B>
				9518
				9519	option forces variables to be created or modified at the global scope,
				9520	even when <B>declare</B> is executed in a shell function.
				9521	It is ignored in all other cases.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9522	The following options can
				9523	be used to restrict output to variables with the specified attribute or
				9524	to give variables attributes:
				9525	<DL COMPACT><DT><DD>
				9526
				9527	<DL COMPACT>
				9528	<DT><B>-a</B>
				9529
				9530	<DD>
				9531	Each <I>name</I> is an indexed array variable (see
				9532	<B>Arrays</B>
				9533
				9534	above).
				9535	<DT><B>-A</B>
				9536
				9537	<DD>
				9538	Each <I>name</I> is an associative array variable (see
				9539	<B>Arrays</B>
				9540
				9541	above).
				9542	<DT><B>-f</B>
				9543
				9544	<DD>
				9545	Use function names only.
				9546	<DT><B>-i</B>
				9547
				9548	<DD>
				9549	The variable is treated as an integer; arithmetic evaluation (see
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9550	<FONT SIZE=-1><B>ARITHMETIC EVALUATION</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9551
				9552	</FONT>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9553	above) is performed when the variable is assigned a value.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9554	<DT><B>-l</B>
				9555
				9556	<DD>
				9557	When the variable is assigned a value, all upper-case characters are
				9558	converted to lower-case.
				9559	The upper-case attribute is disabled.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9560	<DT><B>-n</B>
				9561
				9562	<DD>
				9563	Give each <I>name</I> the <I>nameref</I> attribute, making
				9564	it a name reference to another variable.
				9565	That other variable is defined by the value of <I>name</I>.
				9566	All references and assignments to <I>name</I>, except for changing the
				9567	<B>-n</B> attribute itself, are performed on the variable referenced by
				9568	<I>name</I>'s value.
				9569	The <B>-n</B> attribute cannot be applied to array variables.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9570	<DT><B>-r</B>
				9571
				9572	<DD>
				9573	Make <I>name</I>s readonly. These names cannot then be assigned values
				9574	by subsequent assignment statements or unset.
				9575	<DT><B>-t</B>
				9576
				9577	<DD>
				9578	Give each <I>name</I> the <I>trace</I> attribute.
				9579	Traced functions inherit the <B>DEBUG</B> and <B>RETURN</B> traps from
				9580	the calling shell.
				9581	The trace attribute has no special meaning for variables.
				9582	<DT><B>-u</B>
				9583
				9584	<DD>
				9585	When the variable is assigned a value, all lower-case characters are
				9586	converted to upper-case.
				9587	The lower-case attribute is disabled.
				9588	<DT><B>-x</B>
				9589
				9590	<DD>
				9591	Mark <I>name</I>s for export to subsequent commands via the environment.
				9592
				9593	</DL>
				9594	<P>
				9595
				9596	Using `+' instead of `-'
				9597	turns off the attribute instead,
				9598	with the exceptions that <B>+a</B>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	9599	may not be used to destroy an array variable and <B>+r</B> will not
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9600	remove the readonly attribute.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9601	When used in a function,
				9602	<B>declare</B>
				9603
				9604	and
				9605	<B>typeset</B>
				9606
				9607	make each
				9608	<I>name</I> local, as with the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9609	<B>local</B>
				9610
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9611	command,
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9612	unless the <B>-g</B> option is supplied.
				9613	If a variable name is followed by =<I>value</I>, the value of
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9614	the variable is set to <I>value</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9615	When using <B>-a</B> or <B>-A</B> and the compound assignment syntax to
				9616	create array variables, additional attributes do not take effect until
				9617	subsequent assignments.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9618	The return value is 0 unless an invalid option is encountered,
				9619	an attempt is made to define a function using
				9620
				9621	<TT>-f foo=bar</TT>,
				9622	an attempt is made to assign a value to a readonly variable,
				9623	an attempt is made to assign a value to an array variable without
				9624	using the compound assignment syntax (see
				9625	<B>Arrays</B>
				9626
				9627	above), one of the <I>names</I> is not a valid shell variable name,
				9628	an attempt is made to turn off readonly status for a readonly variable,
				9629	an attempt is made to turn off array status for an array variable,
				9630	or an attempt is made to display a non-existent function with <B>-f</B>.
				9631	</DL>
				9632
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9633	<DT><B>dirs [-clpv</B>] [+<I>n</I>] [-<I>n</I>]
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9634
				9635	<DD>
				9636	Without options, displays the list of currently remembered directories.
				9637	The default display is on a single line with directory names separated
				9638	by spaces.
				9639	Directories are added to the list with the
				9640	<B>pushd</B>
				9641
				9642	command; the
				9643	<B>popd</B>
				9644
				9645	command removes entries from the list.
				9646	<DL COMPACT><DT><DD>
				9647
				9648	<DL COMPACT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9649	<DT><B>-c</B>
				9650
				9651	<DD>
				9652	Clears the directory stack by deleting all of the entries.
				9653	<DT><B>-l</B>
				9654
				9655	<DD>
				9656	Produces a listing using full pathnames;
				9657	the default listing format uses a tilde to denote the home directory.
				9658	<DT><B>-p</B>
				9659
				9660	<DD>
				9661	Print the directory stack with one entry per line.
				9662	<DT><B>-v</B>
				9663
				9664	<DD>
				9665	Print the directory stack with one entry per line,
				9666	prefixing each entry with its index in the stack.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9667	<DT><B>+</B><I>n</I><DD>
				9668	Displays the <I>n</I>th entry counting from the left of the list
				9669	shown by
				9670	<B>dirs</B>
				9671
				9672	when invoked without options, starting with zero.
				9673	<DT><B>-</B><I>n</I><DD>
				9674	Displays the <I>n</I>th entry counting from the right of the list
				9675	shown by
				9676	<B>dirs</B>
				9677
				9678	when invoked without options, starting with zero.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9679
				9680	</DL>
				9681	<P>
				9682
				9683	The return value is 0 unless an
				9684	invalid option is supplied or <I>n</I> indexes beyond the end
				9685	of the directory stack.
				9686	</DL>
				9687
				9688	<DT><B>disown</B> [<B>-ar</B>] [<B>-h</B>] [<I>jobspec</I> ...]<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9689	Without options, remove each
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9690	<I>jobspec</I>
				9691
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9692	from the table of active jobs.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9693	If
				9694	<I>jobspec</I>
				9695
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9696	is not present, and neither the <B>-a</B> nor the <B>-r</B> option
				9697	is supplied, the <I>current job</I> is used.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9698	If the <B>-h</B> option is given, each
				9699	<I>jobspec</I>
				9700
				9701	is not removed from the table, but is marked so that
				9702	<FONT SIZE=-1><B>SIGHUP</B>
				9703
				9704	</FONT>
				9705	is not sent to the job if the shell receives a
				9706	<FONT SIZE=-1><B>SIGHUP</B>.
				9707
				9708	</FONT>
				9709	If no
				9710	<I>jobspec</I>
				9711
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9712	is supplied, the
				9713	<B>-a</B>
				9714
				9715	option means to remove or mark all jobs; the
				9716	<B>-r</B>
				9717
				9718	option without a
				9719	<I>jobspec</I>
				9720
				9721	argument restricts operation to running jobs.
				9722	The return value is 0 unless a
				9723	<I>jobspec</I>
				9724
				9725	does not specify a valid job.
				9726	<DT><B>echo</B> [<B>-neE</B>] [<I>arg</I> ...]<DD>
				9727	Output the <I>arg</I>s, separated by spaces, followed by a newline.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9728	The return status is 0 unless a write error occurs.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9729	If <B>-n</B> is specified, the trailing newline is
				9730	suppressed. If the <B>-e</B> option is given, interpretation of
				9731	the following backslash-escaped characters is enabled. The
				9732	<B>-E</B>
				9733
				9734	option disables the interpretation of these escape characters,
				9735	even on systems where they are interpreted by default.
				9736	The <B>xpg_echo</B> shell option may be used to
				9737	dynamically determine whether or not <B>echo</B> expands these
				9738	escape characters by default.
				9739	<B>echo</B>
				9740
				9741	does not interpret <B>--</B> to mean the end of options.
				9742	<B>echo</B>
				9743
				9744	interprets the following escape sequences:
				9745	<DL COMPACT><DT><DD>
				9746
				9747	<DL COMPACT>
				9748	<DT><B>\a</B>
				9749
				9750	<DD>
				9751	alert (bell)
				9752	<DT><B>\b</B>
				9753
				9754	<DD>
				9755	backspace
				9756	<DT><B>\c</B>
				9757
				9758	<DD>
				9759	suppress further output
				9760	<DT><B>\e</B>
				9761
				9762	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9763	<DT><B>\E</B>
				9764
				9765	<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9766	an escape character
				9767	<DT><B>\f</B>
				9768
				9769	<DD>
				9770	form feed
				9771	<DT><B>\n</B>
				9772
				9773	<DD>
				9774	new line
				9775	<DT><B>\r</B>
				9776
				9777	<DD>
				9778	carriage return
				9779	<DT><B>\t</B>
				9780
				9781	<DD>
				9782	horizontal tab
				9783	<DT><B>\v</B>
				9784
				9785	<DD>
				9786	vertical tab
				9787	<DT><B>\\</B>
				9788
				9789	<DD>
				9790	backslash
				9791	<DT><B>\0</B><I>nnn</I>
				9792
				9793	<DD>
				9794	the eight-bit character whose value is the octal value <I>nnn</I>
				9795	(zero to three octal digits)
				9796	<DT><B>\x</B><I>HH</I>
				9797
				9798	<DD>
				9799	the eight-bit character whose value is the hexadecimal value <I>HH</I>
				9800	(one or two hex digits)
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	9801	<DT><B>\u</B><I>HHHH</I>
				9802
				9803	<DD>
				9804	the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
				9805	<I>HHHH</I> (one to four hex digits)
				9806	<DT><B>\U</B><I>HHHHHHHH</I>
				9807
				9808	<DD>
				9809	the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value
				9810	<I>HHHHHHHH</I> (one to eight hex digits)
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9811
				9812	</DL></DL>
				9813
				9814	<DT><B>enable</B> [<B>-a</B>] [<B>-dnps</B>] [<B>-f</B> <I>filename</I>] [<I>name</I> ...]<DD>
				9815	Enable and disable builtin shell commands.
				9816	Disabling a builtin allows a disk command which has the same name
				9817	as a shell builtin to be executed without specifying a full pathname,
				9818	even though the shell normally searches for builtins before disk commands.
				9819	If <B>-n</B> is used, each <I>name</I>
				9820	is disabled; otherwise,
				9821	<I>names</I> are enabled. For example, to use the
				9822	<B>test</B>
				9823
				9824	binary found via the
				9825	<FONT SIZE=-1><B>PATH</B>
				9826
				9827	</FONT>
				9828	instead of the shell builtin version, run
				9829	<TT>enable -n test</TT>.
				9830
				9831	The
				9832	<B>-f</B>
				9833
				9834	option means to load the new builtin command
				9835	<I>name</I>
				9836
				9837	from shared object
				9838	<I>filename</I>,
				9839
				9840	on systems that support dynamic loading. The
				9841	<B>-d</B>
				9842
				9843	option will delete a builtin previously loaded with
				9844	<B>-f</B>.
				9845
				9846	If no <I>name</I> arguments are given, or if the
				9847	<B>-p</B>
				9848
				9849	option is supplied, a list of shell builtins is printed.
				9850	With no other option arguments, the list consists of all enabled
				9851	shell builtins.
				9852	If <B>-n</B> is supplied, only disabled builtins are printed.
				9853	If <B>-a</B> is supplied, the list printed includes all builtins, with an
				9854	indication of whether or not each is enabled.
				9855	If <B>-s</B> is supplied, the output is restricted to the POSIX
				9856	<I>special</I> builtins.
				9857	The return value is 0 unless a
				9858	<I>name</I>
				9859
				9860	is not a shell builtin or there is an error loading a new builtin
				9861	from a shared object.
				9862	<DT><B>eval</B> [<I>arg</I> ...]<DD>
				9863	The <I>arg</I>s are read and concatenated together into a single
				9864	command. This command is then read and executed by the shell, and
				9865	its exit status is returned as the value of
				9866	<B>eval</B>.
				9867
				9868	If there are no
				9869	<I>args</I>,
				9870
				9871	or only null arguments,
				9872	<B>eval</B>
				9873
				9874	returns 0.
				9875	<DT><B>exec</B> [<B>-cl</B>] [<B>-a</B> <I>name</I>] [<I>command</I> [<I>arguments</I>]]<DD>
				9876	If
				9877	<I>command</I>
				9878
				9879	is specified, it replaces the shell.
				9880	No new process is created. The
				9881	<I>arguments</I>
				9882
				9883	become the arguments to <I>command</I>.
				9884	If the
				9885	<B>-l</B>
				9886
				9887	option is supplied,
				9888	the shell places a dash at the beginning of the zeroth argument passed to
				9889	<I>command</I>.
				9890
				9891	This is what
				9892	<I>login</I>(1)
				9893
				9894	does. The
				9895	<B>-c</B>
				9896
				9897	option causes
				9898	<I>command</I>
				9899
				9900	to be executed with an empty environment. If
				9901	<B>-a</B>
				9902
				9903	is supplied, the shell passes
				9904	<I>name</I>
				9905
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9906	as the zeroth argument to the executed command.
				9907	If
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9908	<I>command</I>
				9909
				9910	cannot be executed for some reason, a non-interactive shell exits,
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9911	unless the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9912	<B>execfail</B>
				9913
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9914	shell option
				9915	is enabled. In that case, it returns failure.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9916	An interactive shell returns failure if the file cannot be executed.
				9917	If
				9918	<I>command</I>
				9919
				9920	is not specified, any redirections take effect in the current shell,
				9921	and the return status is 0. If there is a redirection error, the
				9922	return status is 1.
				9923	<DT><B>exit</B> [<I>n</I>]<DD>
				9924	Cause the shell to exit
				9925	with a status of <I>n</I>. If
				9926	<I>n</I>
				9927
				9928	is omitted, the exit status
				9929	is that of the last command executed.
				9930	A trap on
				9931	<FONT SIZE=-1><B>EXIT</B>
				9932
				9933	</FONT>
				9934	is executed before the shell terminates.
				9935	<DT><B>export</B> [<B>-fn</B>] [<I>name</I>[=<I>word</I>]] ...<DD>
				9936
				9937	<DT><B>export -p</B>
				9938
				9939	<DD>
				9940
				9941	The supplied
				9942	<I>names</I>
				9943
				9944	are marked for automatic export to the environment of
				9945	subsequently executed commands. If the
				9946	<B>-f</B>
				9947
				9948	option is given,
				9949	the
				9950	<I>names</I>
				9951
				9952	refer to functions.
				9953	If no
				9954	<I>names</I>
				9955
				9956	are given, or if the
				9957	<B>-p</B>
				9958
				9959	option is supplied, a list
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9960	of names of all exported variables is printed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9961	The
				9962	<B>-n</B>
				9963
				9964	option causes the export property to be removed from each
				9965	<I>name</I>.
				9966	If a variable name is followed by =<I>word</I>, the value of
				9967	the variable is set to <I>word</I>.
				9968	<B>export</B>
				9969
				9970	returns an exit status of 0 unless an invalid option is
				9971	encountered,
				9972	one of the <I>names</I> is not a valid shell variable name, or
				9973	<B>-f</B>
				9974
				9975	is supplied with a
				9976	<I>name</I>
				9977
				9978	that is not a function.
				9979	<DT><B>fc</B> [<B>-e</B> <I>ename</I>] [<B>-lnr</B>] [<I>first</I>] [<I>last</I>]<DD>
				9980
				9981	<DT><B>fc</B> <B>-s</B> [<I>pat</I>=<I>rep</I>] [<I>cmd</I>]<DD>
				9982
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9983	The first form selects a range of commands from
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9984	<I>first</I>
				9985
				9986	to
				9987	<I>last</I>
				9988
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	9989	from the history list and displays or edits and re-executes them.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	9990	<I>First</I>
				9991
				9992	and
				9993	<I>last</I>
				9994
				9995	may be specified as a string (to locate the last command beginning
				9996	with that string) or as a number (an index into the history list,
				9997	where a negative number is used as an offset from the current
				9998	command number). If
				9999	<I>last</I>
				10000
				10001	is not specified it is set to
				10002	the current command for listing (so that
				10003
				10004	<TT>fc -l -10</TT>
				10005	prints the last 10 commands) and to
				10006	<I>first</I>
				10007
				10008	otherwise.
				10009	If
				10010	<I>first</I>
				10011
				10012	is not specified it is set to the previous
				10013	command for editing and -16 for listing.
				10014	<P>
				10015	The
				10016	<B>-n</B>
				10017
				10018	option suppresses
				10019	the command numbers when listing. The
				10020	<B>-r</B>
				10021
				10022	option reverses the order of
				10023	the commands. If the
				10024	<B>-l</B>
				10025
				10026	option is given,
				10027	the commands are listed on
				10028	standard output. Otherwise, the editor given by
				10029	<I>ename</I>
				10030
				10031	is invoked
				10032	on a file containing those commands. If
				10033	<I>ename</I>
				10034
				10035	is not given, the
				10036	value of the
				10037	<FONT SIZE=-1><B>FCEDIT</B>
				10038
				10039	</FONT>
				10040	variable is used, and
				10041	the value of
				10042	<FONT SIZE=-1><B>EDITOR</B>
				10043
				10044	</FONT>
				10045	if
				10046	<FONT SIZE=-1><B>FCEDIT</B>
				10047
				10048	</FONT>
				10049	is not set. If neither variable is set,
				10050
				10051	<I>vi</I>
				10052
				10053	is used. When editing is complete, the edited commands are
				10054	echoed and executed.
				10055	<P>
				10056	In the second form, <I>command</I> is re-executed after each instance
				10057	of <I>pat</I> is replaced by <I>rep</I>.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10058	<I>Command</I> is intepreted the same as <I>first</I> above.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10059	A useful alias to use with this is
				10060
				10061	<TT>r='fc -s'</TT>,
				10062	so that typing
				10063
				10064	<TT>r cc</TT>
				10065	runs the last command beginning with
				10066
				10067	<TT>cc</TT>
				10068	and typing
				10069
				10070	<TT>r</TT>
				10071	re-executes the last command.
				10072	<P>
				10073	If the first form is used, the return value is 0 unless an invalid
				10074	option is encountered or
				10075	<I>first</I>
				10076
				10077	or
				10078	<I>last</I>
				10079
				10080	specify history lines out of range.
				10081	If the
				10082	<B>-e</B>
				10083
				10084	option is supplied, the return value is the value of the last
				10085	command executed or failure if an error occurs with the temporary
				10086	file of commands. If the second form is used, the return status
				10087	is that of the command re-executed, unless
				10088	<I>cmd</I>
				10089
				10090	does not specify a valid history line, in which case
				10091	<B>fc</B>
				10092
				10093	returns failure.
				10094	<DT><B>fg</B> [<I>jobspec</I>]<DD>
				10095	Resume
				10096	<I>jobspec</I>
				10097
				10098	in the foreground, and make it the current job.
				10099	If
				10100	<I>jobspec</I>
				10101
				10102	is not present, the shell's notion of the <I>current job</I> is used.
				10103	The return value is that of the command placed into the foreground,
				10104	or failure if run when job control is disabled or, when run with
				10105	job control enabled, if
				10106	<I>jobspec</I>
				10107
				10108	does not specify a valid job or
				10109	<I>jobspec</I>
				10110
				10111	specifies a job that was started without job control.
				10112	<DT><B>getopts</B> <I>optstring</I> <I>name</I> [<I>args</I>]<DD>
				10113	<B>getopts</B>
				10114
				10115	is used by shell procedures to parse positional parameters.
				10116	<I>optstring</I>
				10117
				10118	contains the option characters to be recognized; if a character
				10119	is followed by a colon, the option is expected to have an
				10120	argument, which should be separated from it by white space.
				10121	The colon and question mark characters may not be used as
				10122	option characters.
				10123	Each time it is invoked,
				10124	<B>getopts</B>
				10125
				10126	places the next option in the shell variable
				10127	<I>name</I>,
				10128
				10129	initializing
				10130	<I>name</I>
				10131
				10132	if it does not exist,
				10133	and the index of the next argument to be processed into the
				10134	variable
				10135	<FONT SIZE=-1><B>OPTIND</B>.
				10136
				10137	</FONT>
				10138	<FONT SIZE=-1><B>OPTIND</B>
				10139
				10140	</FONT>
				10141	is initialized to 1 each time the shell or a shell script
				10142	is invoked. When an option requires an argument,
				10143	<B>getopts</B>
				10144
				10145	places that argument into the variable
				10146	<FONT SIZE=-1><B>OPTARG</B>.
				10147
				10148	</FONT>
				10149	The shell does not reset
				10150	<FONT SIZE=-1><B>OPTIND</B>
				10151
				10152	</FONT>
				10153	automatically; it must be manually reset between multiple
				10154	calls to
				10155	<B>getopts</B>
				10156
				10157	within the same shell invocation if a new set of parameters
				10158	is to be used.
				10159	<P>
				10160	When the end of options is encountered, <B>getopts</B> exits with a
				10161	return value greater than zero.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10162	<FONT SIZE=-1><B>OPTIND</B>
				10163
				10164	</FONT>
				10165	is set to the index of the first non-option argument,
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10166	and <I>name</I> is set to ?.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10167	<P>
				10168	<B>getopts</B>
				10169
				10170	normally parses the positional parameters, but if more arguments are
				10171	given in
				10172	<I>args</I>,
				10173
				10174	<B>getopts</B>
				10175
				10176	parses those instead.
				10177	<P>
				10178	<B>getopts</B>
				10179
				10180	can report errors in two ways. If the first character of
				10181	<I>optstring</I>
				10182
				10183	is a colon,
				10184	<I>silent</I>
				10185
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10186	error reporting is used. In normal operation, diagnostic messages
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10187	are printed when invalid options or missing option arguments are
				10188	encountered.
				10189	If the variable
				10190	<FONT SIZE=-1><B>OPTERR</B>
				10191
				10192	</FONT>
				10193	is set to 0, no error messages will be displayed, even if the first
				10194	character of
				10195	<I>optstring</I>
				10196
				10197	is not a colon.
				10198	<P>
				10199	If an invalid option is seen,
				10200	<B>getopts</B>
				10201
				10202	places ? into
				10203	<I>name</I>
				10204
				10205	and, if not silent,
				10206	prints an error message and unsets
				10207	<FONT SIZE=-1><B>OPTARG</B>.
				10208
				10209	</FONT>
				10210	If
				10211	<B>getopts</B>
				10212
				10213	is silent,
				10214	the option character found is placed in
				10215	<FONT SIZE=-1><B>OPTARG</B>
				10216
				10217	</FONT>
				10218	and no diagnostic message is printed.
				10219	<P>
				10220	If a required argument is not found, and
				10221	<B>getopts</B>
				10222
				10223	is not silent,
				10224	a question mark (<B>?</B>) is placed in
				10225	<I>name</I>,
				10226
				10227	<FONT SIZE=-1><B>OPTARG</B>
				10228
				10229	</FONT>
				10230	is unset, and a diagnostic message is printed.
				10231	If
				10232	<B>getopts</B>
				10233
				10234	is silent, then a colon (<B>:</B>) is placed in
				10235	<I>name</I>
				10236
				10237	and
				10238	<FONT SIZE=-1><B>OPTARG</B>
				10239
				10240	</FONT>
				10241	is set to the option character found.
				10242	<P>
				10243	<B>getopts</B>
				10244
				10245	returns true if an option, specified or unspecified, is found.
				10246	It returns false if the end of options is encountered or an
				10247	error occurs.
				10248	<DT><B>hash</B> [<B>-lr</B>] [<B>-p</B> <I>filename</I>] [<B>-dt</B>] [<I>name</I>]<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10249	Each time <B>hash</B> is invoked,
				10250	the full pathname of the command
				10251	<I>name</I>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10252
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10253	is determined by searching
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10254	the directories in
				10255	<B>$PATH</B>
				10256
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10257	and remembered. Any previously-remembered pathname is discarded.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10258	If the
				10259	<B>-p</B>
				10260
				10261	option is supplied, no path search is performed, and
				10262	<I>filename</I>
				10263
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10264	is used as the full filename of the command.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10265	The
				10266	<B>-r</B>
				10267
				10268	option causes the shell to forget all
				10269	remembered locations.
				10270	The
				10271	<B>-d</B>
				10272
				10273	option causes the shell to forget the remembered location of each <I>name</I>.
				10274	If the
				10275	<B>-t</B>
				10276
				10277	option is supplied, the full pathname to which each <I>name</I> corresponds
				10278	is printed. If multiple <I>name</I> arguments are supplied with <B>-t</B>,
				10279	the <I>name</I> is printed before the hashed full pathname.
				10280	The
				10281	<B>-l</B>
				10282
				10283	option causes output to be displayed in a format that may be reused as input.
				10284	If no arguments are given, or if only <B>-l</B> is supplied,
				10285	information about remembered commands is printed.
				10286	The return status is true unless a
				10287	<I>name</I>
				10288
				10289	is not found or an invalid option is supplied.
				10290	<DT><B>help</B> [<B>-dms</B>] [<I>pattern</I>]<DD>
				10291	Display helpful information about builtin commands. If
				10292	<I>pattern</I>
				10293
				10294	is specified,
				10295	<B>help</B>
				10296
				10297	gives detailed help on all commands matching
				10298	<I>pattern</I>;
				10299
				10300	otherwise help for all the builtins and shell control structures
				10301	is printed.
				10302	<DL COMPACT><DT><DD>
				10303
				10304	<DL COMPACT>
				10305	<DT><B>-d</B>
				10306
				10307	<DD>
				10308	Display a short description of each <I>pattern</I>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10309	<DT><B>-m</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10310
				10311	<DD>
				10312	Display the description of each <I>pattern</I> in a manpage-like format
				10313	<DT><B>-s</B>
				10314
				10315	<DD>
				10316	Display only a short usage synopsis for each <I>pattern</I>
				10317
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10318	</DL>
				10319	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10320
				10321	The return status is 0 unless no command matches
				10322	<I>pattern</I>.
				10323
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10324	</DL>
				10325
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10326	<DT><B>history [</B><I>n</I>]<DD>
				10327
				10328	<DT><B>history</B> <B>-c</B><DD>
				10329	<DT><B>history -d</B> <I>offset</I><DD>
				10330	<DT><B>history</B> <B>-anrw</B> [<I>filename</I>]<DD>
				10331	<DT><B>history</B> <B>-p</B> <I>arg</I> [<I>arg ...</I>]<DD>
				10332	<DT><B>history</B> <B>-s</B> <I>arg</I> [<I>arg ...</I>]<DD>
				10333
				10334	With no options, display the command
				10335	history list with line numbers. Lines listed
				10336	with a
				10337	<B>*</B>
				10338
				10339	have been modified. An argument of
				10340	<I>n</I>
				10341
				10342	lists only the last
				10343	<I>n</I>
				10344
				10345	lines.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10346	If the shell variable
				10347	<FONT SIZE=-1><B>HISTTIMEFORMAT</B>
				10348
				10349	</FONT>
				10350	is set and not null,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10351	it is used as a format string for <I>strftime</I>(3) to display
				10352	the time stamp associated with each displayed history entry.
				10353	No intervening blank is printed between the formatted time stamp
				10354	and the history line.
				10355	If <I>filename</I> is supplied, it is used as the
				10356	name of the history file; if not, the value of
				10357	<FONT SIZE=-1><B>HISTFILE</B>
				10358
				10359	</FONT>
				10360	is used. Options, if supplied, have the following meanings:
				10361	<DL COMPACT><DT><DD>
				10362
				10363	<DL COMPACT>
				10364	<DT><B>-c</B>
				10365
				10366	<DD>
				10367	Clear the history list by deleting all the entries.
				10368	<DT><B>-d</B> <I>offset</I><DD>
				10369	Delete the history entry at position <I>offset</I>.
				10370	<DT><B>-a</B>
				10371
				10372	<DD>
				10373	Append the ``new'' history lines (history lines entered since the
				10374	beginning of the current <B>bash</B> session) to the history file.
				10375	<DT><B>-n</B>
				10376
				10377	<DD>
				10378	Read the history lines not already read from the history
				10379	file into the current history list. These are lines
				10380	appended to the history file since the beginning of the
				10381	current <B>bash</B> session.
				10382	<DT><B>-r</B>
				10383
				10384	<DD>
				10385	Read the contents of the history file
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10386	and append them to the current history list.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10387	<DT><B>-w</B>
				10388
				10389	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10390	Write the current history list to the history file, overwriting the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10391	history file's contents.
				10392	<DT><B>-p</B>
				10393
				10394	<DD>
				10395	Perform history substitution on the following <I>args</I> and display
				10396	the result on the standard output.
				10397	Does not store the results in the history list.
				10398	Each <I>arg</I> must be quoted to disable normal history expansion.
				10399	<DT><B>-s</B>
				10400
				10401	<DD>
				10402	Store the
				10403	<I>args</I>
				10404
				10405	in the history list as a single entry. The last command in the
				10406	history list is removed before the
				10407	<I>args</I>
				10408
				10409	are added.
				10410
				10411	</DL>
				10412	<P>
				10413
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10414	If the
				10415	<FONT SIZE=-1><B>HISTTIMEFORMAT</B>
				10416
				10417	</FONT>
				10418	variable is set, the time stamp information
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10419	associated with each history entry is written to the history file,
				10420	marked with the history comment character.
				10421	When the history file is read, lines beginning with the history
				10422	comment character followed immediately by a digit are interpreted
				10423	as timestamps for the previous history line.
				10424	The return value is 0 unless an invalid option is encountered, an
				10425	error occurs while reading or writing the history file, an invalid
				10426	<I>offset</I> is supplied as an argument to <B>-d</B>, or the
				10427	history expansion supplied as an argument to <B>-p</B> fails.
				10428	</DL>
				10429
				10430	<DT><B>jobs</B> [<B>-lnprs</B>] [ <I>jobspec</I> ... ]<DD>
				10431
				10432	<DT><B>jobs</B> <B>-x</B> <I>command</I> [ <I>args</I> ... ]<DD>
				10433
				10434	The first form lists the active jobs. The options have the following
				10435	meanings:
				10436	<DL COMPACT><DT><DD>
				10437
				10438	<DL COMPACT>
				10439	<DT><B>-l</B>
				10440
				10441	<DD>
				10442	List process IDs
				10443	in addition to the normal information.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10444	<DT><B>-n</B>
				10445
				10446	<DD>
				10447	Display information only about jobs that have changed status since
				10448	the user was last notified of their status.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10449	<DT><B>-p</B>
				10450
				10451	<DD>
				10452	List only the process ID of the job's process group
				10453	leader.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10454	<DT><B>-r</B>
				10455
				10456	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10457	Display only running jobs.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10458	<DT><B>-s</B>
				10459
				10460	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10461	Display only stopped jobs.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10462
				10463	</DL>
				10464	<P>
				10465
				10466	If
				10467	<I>jobspec</I>
				10468
				10469	is given, output is restricted to information about that job.
				10470	The return status is 0 unless an invalid option is encountered
				10471	or an invalid
				10472	<I>jobspec</I>
				10473
				10474	is supplied.
				10475	<P>
				10476
				10477	If the
				10478	<B>-x</B>
				10479
				10480	option is supplied,
				10481	<B>jobs</B>
				10482
				10483	replaces any
				10484	<I>jobspec</I>
				10485
				10486	found in
				10487	<I>command</I>
				10488
				10489	or
				10490	<I>args</I>
				10491
				10492	with the corresponding process group ID, and executes
				10493	<I>command</I>
				10494
				10495	passing it
				10496	<I>args</I>,
				10497
				10498	returning its exit status.
				10499	</DL>
				10500
				10501	<DT><B>kill</B> [<B>-s</B> <I>sigspec</I> \| <B>-n</B> <I>signum</I> \| <B>-</B><I>sigspec</I>] [<I>pid</I> \| <I>jobspec</I>] ...<DD>
				10502
				10503	<DT><B>kill</B> <B>-l</B> [<I>sigspec</I> \| <I>exit_status</I>]<DD>
				10504
				10505	Send the signal named by
				10506	<I>sigspec</I>
				10507
				10508	or
				10509	<I>signum</I>
				10510
				10511	to the processes named by
				10512	<I>pid</I>
				10513
				10514	or
				10515	<I>jobspec</I>.
				10516
				10517	<I>sigspec</I>
				10518
				10519	is either a case-insensitive signal name such as
				10520	<FONT SIZE=-1><B>SIGKILL</B>
				10521
				10522	</FONT>
				10523	(with or without the
				10524	<FONT SIZE=-1><B>SIG</B>
				10525
				10526	</FONT>
				10527	prefix) or a signal number;
				10528	<I>signum</I>
				10529
				10530	is a signal number.
				10531	If
				10532	<I>sigspec</I>
				10533
				10534	is not present, then
				10535	<FONT SIZE=-1><B>SIGTERM</B>
				10536
				10537	</FONT>
				10538	is assumed.
				10539	An argument of
				10540	<B>-l</B>
				10541
				10542	lists the signal names.
				10543	If any arguments are supplied when
				10544	<B>-l</B>
				10545
				10546	is given, the names of the signals corresponding to the arguments are
				10547	listed, and the return status is 0.
				10548	The <I>exit_status</I> argument to
				10549	<B>-l</B>
				10550
				10551	is a number specifying either a signal number or the exit status of
				10552	a process terminated by a signal.
				10553	<B>kill</B>
				10554
				10555	returns true if at least one signal was successfully sent, or false
				10556	if an error occurs or an invalid option is encountered.
				10557	<DT><B>let</B> <I>arg</I> [<I>arg</I> ...]<DD>
				10558	Each
				10559	<I>arg</I>
				10560
				10561	is an arithmetic expression to be evaluated (see
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10562	<FONT SIZE=-1><B>ARITHMETIC EVALUATION</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10563
				10564	</FONT>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10565	above).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10566	If the last
				10567	<I>arg</I>
				10568
				10569	evaluates to 0,
				10570	<B>let</B>
				10571
				10572	returns 1; 0 is returned otherwise.
				10573	<DT><B>local</B> [<I>option</I>] [<I>name</I>[=<I>value</I>] ...]<DD>
				10574	For each argument, a local variable named
				10575	<I>name </I>
				10576
				10577	is created, and assigned
				10578	<I>value</I>.
				10579
				10580	The <I>option</I> can be any of the options accepted by <B>declare</B>.
				10581	When
				10582	<B>local</B>
				10583
				10584	is used within a function, it causes the variable
				10585	<I>name</I>
				10586
				10587	to have a visible scope restricted to that function and its children.
				10588	With no operands,
				10589	<B>local</B>
				10590
				10591	writes a list of local variables to the standard output. It is
				10592	an error to use
				10593	<B>local</B>
				10594
				10595	when not within a function. The return status is 0 unless
				10596	<B>local</B>
				10597
				10598	is used outside a function, an invalid
				10599	<I>name</I>
				10600
				10601	is supplied, or
				10602	<I>name</I> is a readonly variable.
				10603	<DT><B>logout</B>
				10604
				10605	<DD>
				10606	Exit a login shell.
				10607	<DT><B>mapfile</B> [<B>-n</B> <I>count</I>] [<B>-O</B> <I>origin</I>] [<B>-s</B> <I>count</I>] [<B>-t</B>] [<B>-u</B> <I>fd</I>] [<B>-C</B> <I>callback</I>] [<B>-c</B> <I>quantum</I>] [<I>array</I>]<DD>
				10608
				10609	<DT><B>readarray</B> [<B>-n</B> <I>count</I>] [<B>-O</B> <I>origin</I>] [<B>-s</B> <I>count</I>] [<B>-t</B>] [<B>-u</B> <I>fd</I>] [<B>-C</B> <I>callback</I>] [<B>-c</B> <I>quantum</I>] [<I>array</I>]<DD>
				10610
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10611	Read lines from the standard input into the indexed array variable
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10612	<I>array</I>,
				10613
				10614	or from file descriptor
				10615	<I>fd</I>
				10616
				10617	if the
				10618	<B>-u</B>
				10619
				10620	option is supplied.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10621	The variable
				10622	<FONT SIZE=-1><B>MAPFILE</B>
				10623
				10624	</FONT>
				10625	is the default <I>array</I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10626	Options, if supplied, have the following meanings:
				10627	<DL COMPACT><DT><DD>
				10628
				10629	<DL COMPACT>
				10630	<DT><B>-n</B>
				10631
				10632	<DD>
				10633	Copy at most
				10634	<I>count</I>
				10635
				10636	lines. If <I>count</I> is 0, all lines are copied.
				10637	<DT><B>-O</B>
				10638
				10639	<DD>
				10640	Begin assigning to
				10641	<I>array</I>
				10642
				10643	at index
				10644	<I>origin</I>.
				10645
				10646	The default index is 0.
				10647	<DT><B>-s</B>
				10648
				10649	<DD>
				10650	Discard the first <I>count</I> lines read.
				10651	<DT><B>-t</B>
				10652
				10653	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10654	Remove a trailing newline from each line read.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10655	<DT><B>-u</B>
				10656
				10657	<DD>
				10658	Read lines from file descriptor <I>fd</I> instead of the standard input.
				10659	<DT><B>-C</B>
				10660
				10661	<DD>
				10662	Evaluate
				10663	<I>callback</I>
				10664
				10665	each time <I>quantum</I> lines are read. The <B>-c</B> option specifies
				10666	<I>quantum</I>.
				10667
				10668	<DT><B>-c</B>
				10669
				10670	<DD>
				10671	Specify the number of lines read between each call to
				10672	<I>callback</I>.
				10673
				10674
				10675	</DL>
				10676	<P>
				10677
				10678	If
				10679	<B>-C</B>
				10680
				10681	is specified without
				10682	<B>-c</B>,
				10683
				10684	the default quantum is 5000.
				10685	When <I>callback</I> is evaluated, it is supplied the index of the next
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10686	array element to be assigned and the line to be assigned to that element
				10687	as additional arguments.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10688	<I>callback</I> is evaluated after the line is read but before the
				10689	array element is assigned.
				10690	<P>
				10691
				10692	If not supplied with an explicit origin, <B>mapfile</B> will clear <I>array</I>
				10693	before assigning to it.
				10694	<P>
				10695
				10696	<B>mapfile</B> returns successfully unless an invalid option or option
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10697	argument is supplied, <I>array</I> is invalid or unassignable, or if
				10698	<I>array</I> is not an indexed array.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10699	</DL>
				10700
				10701	<DT><B>popd</B> [-<B>n</B>] [+<I>n</I>] [-<I>n</I>]<DD>
				10702	Removes entries from the directory stack. With no arguments,
				10703	removes the top directory from the stack, and performs a
				10704	<B>cd</B>
				10705
				10706	to the new top directory.
				10707	Arguments, if supplied, have the following meanings:
				10708	<DL COMPACT><DT><DD>
				10709
				10710	<DL COMPACT>
				10711	<DT><B>-n</B>
				10712
				10713	<DD>
				10714	Suppresses the normal change of directory when removing directories
				10715	from the stack, so that only the stack is manipulated.
				10716	<DT><B>+</B><I>n</I><DD>
				10717	Removes the <I>n</I>th entry counting from the left of the list
				10718	shown by
				10719	<B>dirs</B>,
				10720
				10721	starting with zero. For example:
				10722
				10723	<TT>popd +0</TT>
				10724	removes the first directory,
				10725
				10726	<TT>popd +1</TT>
				10727	the second.
				10728	<DT><B>-</B><I>n</I><DD>
				10729	Removes the <I>n</I>th entry counting from the right of the list
				10730	shown by
				10731	<B>dirs</B>,
				10732
				10733	starting with zero. For example:
				10734
				10735	<TT>popd -0</TT>
				10736	removes the last directory,
				10737
				10738	<TT>popd -1</TT>
				10739	the next to last.
				10740
				10741	</DL>
				10742	<P>
				10743
				10744	If the
				10745	<B>popd</B>
				10746
				10747	command is successful, a
				10748	<B>dirs</B>
				10749
				10750	is performed as well, and the return status is 0.
				10751	<B>popd</B>
				10752
				10753	returns false if an invalid option is encountered, the directory stack
				10754	is empty, a non-existent directory stack entry is specified, or the
				10755	directory change fails.
				10756	</DL>
				10757
				10758	<DT><B>printf</B> [<B>-v</B> <I>var</I>] <I>format</I> [<I>arguments</I>]<DD>
				10759	Write the formatted <I>arguments</I> to the standard output under the
				10760	control of the <I>format</I>.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10761	The <B>-v</B> option causes the output to be assigned to the variable
				10762	<I>var</I> rather than being printed to the standard output.
				10763	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10764	The <I>format</I> is a character string which contains three types of objects:
				10765	plain characters, which are simply copied to standard output, character
				10766	escape sequences, which are converted and copied to the standard output, and
				10767	format specifications, each of which causes printing of the next successive
				10768	<I>argument</I>.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10769	In addition to the standard <I>printf</I>(1) format specifications,
				10770	<B>printf</B> interprets the following extensions:
				10771	<DL COMPACT><DT><DD>
				10772
				10773	<DL COMPACT>
				10774	<DT><B>%b</B>
				10775
				10776	<DD>
				10777	causes
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10778	<B>printf</B> to expand backslash escape sequences in the corresponding
				10779	<I>argument</I> (except that <B>\c</B> terminates output, backslashes in
				10780	<B>\aq</B>, <B>\"</B>, and <B>\?</B> are not removed, and octal escapes
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10781	beginning with <B>\0</B> may contain up to four digits).
				10782	<DT><B>%q</B>
				10783
				10784	<DD>
				10785	causes <B>printf</B> to output the corresponding
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10786	<I>argument</I> in a format that can be reused as shell input.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10787	<DT><B>%(</B><I>datefmt</I>)T
				10788
				10789	<DD>
				10790	causes <B>printf</B> to output the date-time string resulting from using
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10791	<I>datefmt</I> as a format string for <I>strftime</I>(3).
				10792	The corresponding <I>argument</I> is an integer representing the number of
				10793	seconds since the epoch.
				10794	Two special argument values may be used: -1 represents the current
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10795	time, and -2 represents the time the shell was invoked.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10796	If no argument is specified, conversion behaves as if -1 had been given.
				10797	This is an exception to the usual <B>printf</B> behavior.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10798
				10799	</DL>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10800	<P>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10801
				10802	Arguments to non-string format specifiers are treated as C constants,
				10803	except that a leading plus or minus sign is allowed, and if the leading
				10804	character is a single or double quote, the value is the ASCII value of
				10805	the following character.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10806	<P>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10807
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10808	The <I>format</I> is reused as necessary to consume all of the <I>arguments</I>.
				10809	If the <I>format</I> requires more <I>arguments</I> than are supplied, the
				10810	extra format specifications behave as if a zero value or null string, as
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	10811	appropriate, had been supplied.
				10812	The return value is zero on success, non-zero on failure.
				10813	</DL>
				10814
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10815	<DT><B>pushd</B> [<B>-n</B>] [+<I>n</I>] [-<I>n</I>]<DD>
				10816
				10817	<DT><B>pushd</B> [<B>-n</B>] [<I>dir</I>]<DD>
				10818
				10819	Adds a directory to the top of the directory stack, or rotates
				10820	the stack, making the new top of the stack the current working
				10821	directory. With no arguments, exchanges the top two directories
				10822	and returns 0, unless the directory stack is empty.
				10823	Arguments, if supplied, have the following meanings:
				10824	<DL COMPACT><DT><DD>
				10825
				10826	<DL COMPACT>
				10827	<DT><B>-n</B>
				10828
				10829	<DD>
				10830	Suppresses the normal change of directory when adding directories
				10831	to the stack, so that only the stack is manipulated.
				10832	<DT><B>+</B><I>n</I><DD>
				10833	Rotates the stack so that the <I>n</I>th directory
				10834	(counting from the left of the list shown by
				10835	<B>dirs</B>,
				10836
				10837	starting with zero)
				10838	is at the top.
				10839	<DT><B>-</B><I>n</I><DD>
				10840	Rotates the stack so that the <I>n</I>th directory
				10841	(counting from the right of the list shown by
				10842	<B>dirs</B>,
				10843
				10844	starting with zero) is at the top.
				10845	<DT><I>dir</I>
				10846
				10847	<DD>
				10848	Adds
				10849	<I>dir</I>
				10850
				10851	to the directory stack at the top, making it the
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10852	new current working directory as if it had been supplied as the argument
				10853	to the <B>cd</B> builtin.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10854
				10855	</DL>
				10856	<P>
				10857
				10858	If the
				10859	<B>pushd</B>
				10860
				10861	command is successful, a
				10862	<B>dirs</B>
				10863
				10864	is performed as well.
				10865	If the first form is used,
				10866	<B>pushd</B>
				10867
				10868	returns 0 unless the cd to
				10869	<I>dir</I>
				10870
				10871	fails. With the second form,
				10872	<B>pushd</B>
				10873
				10874	returns 0 unless the directory stack is empty,
				10875	a non-existent directory stack element is specified,
				10876	or the directory change to the specified new current directory
				10877	fails.
				10878	</DL>
				10879
				10880	<DT><B>pwd</B> [<B>-LP</B>]<DD>
				10881	Print the absolute pathname of the current working directory.
				10882	The pathname printed contains no symbolic links if the
				10883	<B>-P</B>
				10884
				10885	option is supplied or the
				10886	<B>-o physical</B>
				10887
				10888	option to the
				10889	<B>set</B>
				10890
				10891	builtin command is enabled.
				10892	If the
				10893	<B>-L</B>
				10894
				10895	option is used, the pathname printed may contain symbolic links.
				10896	The return status is 0 unless an error occurs while
				10897	reading the name of the current directory or an
				10898	invalid option is supplied.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10899	<DT><B>read</B> [<B>-ers</B>] [<B>-a</B> <I>aname</I>] [<B>-d</B> <I>delim</I>] [<B>-i</B> <I>text</I>] [<B>-n</B> <I>nchars</I>] [<B>-N</B> <I>nchars</I>] [<B>-p</B> <I>prompt</I>] [<B>-t</B> <I>timeout</I>] [<B>-u</B> <I>fd</I>] [<I>name</I> ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10900	One line is read from the standard input, or from the file descriptor
				10901	<I>fd</I> supplied as an argument to the <B>-u</B> option, and the first word
				10902	is assigned to the first
				10903	<I>name</I>,
				10904
				10905	the second word to the second
				10906	<I>name</I>,
				10907
				10908	and so on, with leftover words and their intervening separators assigned
				10909	to the last
				10910	<I>name</I>.
				10911
				10912	If there are fewer words read from the input stream than names,
				10913	the remaining names are assigned empty values.
				10914	The characters in
				10915	<FONT SIZE=-1><B>IFS</B>
				10916
				10917	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	10918	are used to split the line into words using the same rules the shell
				10919	uses for expansion (described above under <B>Word Splitting</B>).
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10920	The backslash character (<B>\</B>) may be used to remove any special
				10921	meaning for the next character read and for line continuation.
				10922	Options, if supplied, have the following meanings:
				10923	<DL COMPACT><DT><DD>
				10924
				10925	<DL COMPACT>
				10926	<DT><B>-a </B><I>aname</I>
				10927
				10928	<DD>
				10929	The words are assigned to sequential indices
				10930	of the array variable
				10931	<I>aname</I>,
				10932
				10933	starting at 0.
				10934	<I>aname</I>
				10935
				10936	is unset before any new values are assigned.
				10937	Other <I>name</I> arguments are ignored.
				10938	<DT><B>-d </B><I>delim</I>
				10939
				10940	<DD>
				10941	The first character of <I>delim</I> is used to terminate the input line,
				10942	rather than newline.
				10943	<DT><B>-e</B>
				10944
				10945	<DD>
				10946	If the standard input
				10947	is coming from a terminal,
				10948	<B>readline</B>
				10949
				10950	(see
				10951	<FONT SIZE=-1><B>READLINE</B>
				10952
				10953	</FONT>
				10954	above) is used to obtain the line.
				10955	Readline uses the current (or default, if line editing was not previously
				10956	active) editing settings.
				10957	<DT><B>-i </B><I>text</I>
				10958
				10959	<DD>
				10960	If
				10961	<B>readline</B>
				10962
				10963	is being used to read the line, <I>text</I> is placed into the editing
				10964	buffer before editing begins.
				10965	<DT><B>-n </B><I>nchars</I>
				10966
				10967	<DD>
				10968	<B>read</B> returns after reading <I>nchars</I> characters rather than
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	10969	waiting for a complete line of input, but honor a delimiter if fewer
				10970	than <I>nchars</I> characters are read before the delimiter.
				10971	<DT><B>-N </B><I>nchars</I>
				10972
				10973	<DD>
				10974	<B>read</B> returns after reading exactly <I>nchars</I> characters rather
				10975	than waiting for a complete line of input, unless EOF is encountered or
				10976	<B>read</B> times out.
				10977	Delimiter characters encountered in the input are
				10978	not treated specially and do not cause <B>read</B> to return until
				10979	<I>nchars</I> characters are read.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	10980	<DT><B>-p </B><I>prompt</I>
				10981
				10982	<DD>
				10983	Display <I>prompt</I> on standard error, without a
				10984	trailing newline, before attempting to read any input. The prompt
				10985	is displayed only if input is coming from a terminal.
				10986	<DT><B>-r</B>
				10987
				10988	<DD>
				10989	Backslash does not act as an escape character.
				10990	The backslash is considered to be part of the line.
				10991	In particular, a backslash-newline pair may not be used as a line
				10992	continuation.
				10993	<DT><B>-s</B>
				10994
				10995	<DD>
				10996	Silent mode. If input is coming from a terminal, characters are
				10997	not echoed.
				10998	<DT><B>-t </B><I>timeout</I>
				10999
				11000	<DD>
				11001	Cause <B>read</B> to time out and return failure if a complete line of
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11002	input (or a specified number of characters)
				11003	is not read within <I>timeout</I> seconds.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11004	<I>timeout</I> may be a decimal number with a fractional portion following
				11005	the decimal point.
				11006	This option is only effective if <B>read</B> is reading input from a
				11007	terminal, pipe, or other special file; it has no effect when reading
				11008	from regular files.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11009	If <B>read</B> times out, <B>read</B> saves any partial input read into
				11010	the specified variable <I>name</I>.
				11011	If <I>timeout</I> is 0, <B>read</B> returns immediately, without trying to
				11012	read any data. The exit status is 0 if input is available on
				11013	the specified file descriptor, non-zero otherwise.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11014	The exit status is greater than 128 if the timeout is exceeded.
				11015	<DT><B>-u </B><I>fd</I>
				11016
				11017	<DD>
				11018	Read input from file descriptor <I>fd</I>.
				11019
				11020	</DL>
				11021	<P>
				11022
				11023	If no
				11024	<I>names</I>
				11025
				11026	are supplied, the line read is assigned to the variable
				11027	<FONT SIZE=-1><B>REPLY</B>.
				11028
				11029	</FONT>
				11030	The return code is zero, unless end-of-file is encountered, <B>read</B>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11031	times out (in which case the return code is greater than 128),
				11032	a variable assignment error (such as assigning to a readonly variable) occurs,
				11033	or an invalid file descriptor is supplied as the argument to <B>-u</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11034	</DL>
				11035
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11036	<DT><B>readonly</B> [<B>-aAf</B>] [<B>-p</B>] [<I>name</I>[=<I>word</I>] ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11037
				11038	The given
				11039	<I>names</I> are marked readonly; the values of these
				11040	<I>names</I>
				11041
				11042	may not be changed by subsequent assignment.
				11043	If the
				11044	<B>-f</B>
				11045
				11046	option is supplied, the functions corresponding to the
				11047	<I>names</I> are so
				11048	marked.
				11049	The
				11050	<B>-a</B>
				11051
				11052	option restricts the variables to indexed arrays; the
				11053	<B>-A</B>
				11054
				11055	option restricts the variables to associative arrays.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11056	If both options are supplied,
				11057	<B>-A</B>
				11058
				11059	takes precedence.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11060	If no
				11061	<I>name</I>
				11062
				11063	arguments are given, or if the
				11064	<B>-p</B>
				11065
				11066	option is supplied, a list of all readonly names is printed.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11067	The other options may be used to restrict the output to a subset of
				11068	the set of readonly names.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11069	The
				11070	<B>-p</B>
				11071
				11072	option causes output to be displayed in a format that
				11073	may be reused as input.
				11074	If a variable name is followed by =<I>word</I>, the value of
				11075	the variable is set to <I>word</I>.
				11076	The return status is 0 unless an invalid option is encountered,
				11077	one of the
				11078	<I>names</I>
				11079
				11080	is not a valid shell variable name, or
				11081	<B>-f</B>
				11082
				11083	is supplied with a
				11084	<I>name</I>
				11085
				11086	that is not a function.
				11087	<DT><B>return</B> [<I>n</I>]<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11088	Causes a function to stop executing and return the value specified by
				11089	<I>n</I>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11090
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11091	to its caller.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11092	If
				11093	<I>n</I>
				11094
				11095	is omitted, the return status is that of the last command
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11096	executed in the function body. If
				11097	<B>return</B>
				11098
				11099	is used outside a function,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11100	but during execution of a script by the
				11101	<B>.</B>
				11102
				11103	(<B>source</B>) command, it causes the shell to stop executing
				11104	that script and return either
				11105	<I>n</I>
				11106
				11107	or the exit status of the last command executed within the
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11108	script as the exit status of the script.
				11109	If <I>n</I> is supplied, the return value is its least significant
				11110	8 bits.
				11111	The return status is non-zero if
				11112	<B>return</B>
				11113
				11114	is supplied a non-numeric argument, or
				11115	is used outside a
				11116	function and not during execution of a script by <B>.</B> or <B>source</B>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11117	Any command associated with the <B>RETURN</B> trap is executed
				11118	before execution resumes after the function or script.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	11119	<DT><B>set</B> [<B>--abefhkmnptuvxBCEHPT</B>] [<B>-o</B> <I>option-name</I>] [<I>arg</I> ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11120
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	11121	<DT><B>set</B> [<B>+abefhkmnptuvxBCEHPT</B>] [<B>+o</B> <I>option-name</I>] [<I>arg</I> ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11122
				11123	Without options, the name and value of each shell variable are displayed
				11124	in a format that can be reused as input
				11125	for setting or resetting the currently-set variables.
				11126	Read-only variables cannot be reset.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11127	In <I>posix</I> mode, only shell variables are listed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11128	The output is sorted according to the current locale.
				11129	When options are specified, they set or unset shell attributes.
				11130	Any arguments remaining after option processing are treated
				11131	as values for the positional parameters and are assigned, in order, to
				11132	<B>$1</B>,
				11133
				11134	<B>$2</B>,
				11135
				11136	<B>...</B>
				11137
				11138	<B>$</B><I>n</I>.
				11139
				11140	Options, if specified, have the following meanings:
				11141	<DL COMPACT><DT><DD>
				11142
				11143	<DL COMPACT>
				11144	<DT><B>-a</B>
				11145
				11146	<DD>
				11147	Automatically mark variables and functions which are modified or
				11148	created for export to the environment of subsequent commands.
				11149	<DT><B>-b</B>
				11150
				11151	<DD>
				11152	Report the status of terminated background jobs
				11153	immediately, rather than before the next primary prompt. This is
				11154	effective only when job control is enabled.
				11155	<DT><B>-e</B>
				11156
				11157	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11158	Exit immediately if a
				11159	<I>pipeline</I> (which may consist of a single <I>simple command</I>),
				11160	a <I>list</I>,
				11161	or a <I>compound command</I>
				11162	(see
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11163	<FONT SIZE=-1><B>SHELL GRAMMAR</B>
				11164
				11165	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11166	above), exits with a non-zero status.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11167	The shell does not exit if the
				11168	command that fails is part of the command list immediately following a
				11169	<B>while</B>
				11170
				11171	or
				11172	<B>until</B>
				11173
				11174	keyword,
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11175	part of the test following the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11176	<B>if</B>
				11177
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11178	or
				11179	<B>elif</B>
				11180
				11181	reserved words, part of any command executed in a
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11182	<B>&&</B>
				11183
				11184	or
				11185	<B>\|\|</B>
				11186
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11187	list except the command following the final <B>&&</B> or <B>\|\|</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11188	any command in a pipeline but the last,
				11189	or if the command's return value is
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11190	being inverted with
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11191	<B>!</B>.
				11192
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11193	If a compound command other than a subshell
				11194	returns a non-zero status because a command failed
				11195	while <B>-e</B> was being ignored, the shell does not exit.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11196	A trap on <B>ERR</B>, if set, is executed before the shell exits.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11197	This option applies to the shell environment and each subshell environment
				11198	separately (see
				11199	<FONT SIZE=-1><B>COMMAND EXECUTION ENVIRONMENT</B>
				11200
				11201	</FONT>
				11202	above), and may cause
				11203	subshells to exit before executing all the commands in the subshell.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11204	<P>
				11205
				11206
				11207	If a compound command or shell function executes in a context
				11208	where <B>-e</B> is being ignored,
				11209	none of the commands executed within the compound command or function body
				11210	will be affected by the <B>-e</B> setting, even if <B>-e</B> is set
				11211	and a command returns a failure status.
				11212	If a compound command or shell function sets <B>-e</B> while executing in
				11213	a context where <B>-e</B> is ignored, that setting will not have any
				11214	effect until the compound command or the command containing the function
				11215	call completes.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11216	<DT><B>-f</B>
				11217
				11218	<DD>
				11219	Disable pathname expansion.
				11220	<DT><B>-h</B>
				11221
				11222	<DD>
				11223	Remember the location of commands as they are looked up for execution.
				11224	This is enabled by default.
				11225	<DT><B>-k</B>
				11226
				11227	<DD>
				11228	All arguments in the form of assignment statements
				11229	are placed in the environment for a command, not just
				11230	those that precede the command name.
				11231	<DT><B>-m</B>
				11232
				11233	<DD>
				11234	Monitor mode. Job control is enabled. This option is on
				11235	by default for interactive shells on systems that support
				11236	it (see
				11237	<FONT SIZE=-1><B>JOB CONTROL</B>
				11238
				11239	</FONT>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11240	above).
				11241	All processes run in a separate process group.
				11242	When a background job completes, the shell prints a line
				11243	containing its exit status.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11244	<DT><B>-n</B>
				11245
				11246	<DD>
				11247	Read commands but do not execute them. This may be used to
				11248	check a shell script for syntax errors. This is ignored by
				11249	interactive shells.
				11250	<DT><B>-o </B><I>option-name</I>
				11251
				11252	<DD>
				11253	The <I>option-name</I> can be one of the following:
				11254	<DL COMPACT><DT><DD>
				11255	<DL COMPACT>
				11256	<DT><B>allexport</B>
				11257
				11258	<DD>
				11259	Same as
				11260	<B>-a</B>.
				11261
				11262	<DT><B>braceexpand</B>
				11263
				11264	<DD>
				11265	Same as
				11266	<B>-B</B>.
				11267
				11268	<DT><B>emacs</B>
				11269
				11270	<DD>
				11271	Use an emacs-style command line editing interface. This is enabled
				11272	by default when the shell is interactive, unless the shell is started
				11273	with the
				11274	<B>--noediting</B>
				11275
				11276	option.
				11277	This also affects the editing interface used for <B>read -e</B>.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11278	<DT><B>errexit</B>
				11279
				11280	<DD>
				11281	Same as
				11282	<B>-e</B>.
				11283
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11284	<DT><B>errtrace</B>
				11285
				11286	<DD>
				11287	Same as
				11288	<B>-E</B>.
				11289
				11290	<DT><B>functrace</B>
				11291
				11292	<DD>
				11293	Same as
				11294	<B>-T</B>.
				11295
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11296	<DT><B>hashall</B>
				11297
				11298	<DD>
				11299	Same as
				11300	<B>-h</B>.
				11301
				11302	<DT><B>histexpand</B>
				11303
				11304	<DD>
				11305	Same as
				11306	<B>-H</B>.
				11307
				11308	<DT><B>history</B>
				11309
				11310	<DD>
				11311	Enable command history, as described above under
				11312	<FONT SIZE=-1><B>HISTORY</B>.
				11313
				11314	</FONT>
				11315	This option is on by default in interactive shells.
				11316	<DT><B>ignoreeof</B>
				11317
				11318	<DD>
				11319	The effect is as if the shell command
				11320	<TT>IGNOREEOF=10</TT>
				11321
				11322	had been executed
				11323	(see
				11324	<B>Shell Variables</B>
				11325
				11326	above).
				11327	<DT><B>keyword</B>
				11328
				11329	<DD>
				11330	Same as
				11331	<B>-k</B>.
				11332
				11333	<DT><B>monitor</B>
				11334
				11335	<DD>
				11336	Same as
				11337	<B>-m</B>.
				11338
				11339	<DT><B>noclobber</B>
				11340
				11341	<DD>
				11342	Same as
				11343	<B>-C</B>.
				11344
				11345	<DT><B>noexec</B>
				11346
				11347	<DD>
				11348	Same as
				11349	<B>-n</B>.
				11350
				11351	<DT><B>noglob</B>
				11352
				11353	<DD>
				11354	Same as
				11355	<B>-f</B>.
				11356
				11357	<DT><B>nolog</B>
				11358
				11359	<DD>
				11360	Currently ignored.
				11361	<DT><B>notify</B>
				11362
				11363	<DD>
				11364	Same as
				11365	<B>-b</B>.
				11366
				11367	<DT><B>nounset</B>
				11368
				11369	<DD>
				11370	Same as
				11371	<B>-u</B>.
				11372
				11373	<DT><B>onecmd</B>
				11374
				11375	<DD>
				11376	Same as
				11377	<B>-t</B>.
				11378
				11379	<DT><B>physical</B>
				11380
				11381	<DD>
				11382	Same as
				11383	<B>-P</B>.
				11384
				11385	<DT><B>pipefail</B>
				11386
				11387	<DD>
				11388	If set, the return value of a pipeline is the value of the last
				11389	(rightmost) command to exit with a non-zero status, or zero if all
				11390	commands in the pipeline exit successfully.
				11391	This option is disabled by default.
				11392	<DT><B>posix</B>
				11393
				11394	<DD>
				11395	Change the behavior of
				11396	<B>bash</B>
				11397
				11398	where the default operation differs
				11399	from the POSIX standard to match the standard (<I>posix mode</I>).
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11400	See
				11401	<FONT SIZE=-1><B>SEE ALSO</B>
				11402
				11403	</FONT>
				11404	below for a reference to a document that details how posix mode affects
				11405	bash's behavior.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11406	<DT><B>privileged</B>
				11407
				11408	<DD>
				11409	Same as
				11410	<B>-p</B>.
				11411
				11412	<DT><B>verbose</B>
				11413
				11414	<DD>
				11415	Same as
				11416	<B>-v</B>.
				11417
				11418	<DT><B>vi</B>
				11419
				11420	<DD>
				11421	Use a vi-style command line editing interface.
				11422	This also affects the editing interface used for <B>read -e</B>.
				11423	<DT><B>xtrace</B>
				11424
				11425	<DD>
				11426	Same as
				11427	<B>-x</B>.
				11428
				11429	<P>
				11430	</DL>
				11431	<P>
				11432
				11433	If
				11434	<B>-o</B>
				11435
				11436	is supplied with no <I>option-name</I>, the values of the current options are
				11437	printed.
				11438	If
				11439	<B>+o</B>
				11440
				11441	is supplied with no <I>option-name</I>, a series of
				11442	<B>set</B>
				11443
				11444	commands to recreate the current option settings is displayed on
				11445	the standard output.
				11446	</DL>
				11447
				11448	<DT><B>-p</B>
				11449
				11450	<DD>
				11451	Turn on
				11452	<I>privileged</I>
				11453
				11454	mode. In this mode, the
				11455	<FONT SIZE=-1><B>$ENV</B>
				11456
				11457	</FONT>
				11458	and
				11459	<FONT SIZE=-1><B>$BASH_ENV</B>
				11460
				11461	</FONT>
				11462	files are not processed, shell functions are not inherited from the
				11463	environment, and the
				11464	<FONT SIZE=-1><B>SHELLOPTS</B>,
				11465
				11466	</FONT>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11467	<FONT SIZE=-1><B>BASHOPTS</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11468
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11469	</FONT>
				11470	<FONT SIZE=-1><B>CDPATH</B>,
				11471
				11472	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11473	and
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11474	<FONT SIZE=-1><B>GLOBIGNORE</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11475
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11476	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11477	variables, if they appear in the environment, are ignored.
				11478	If the shell is started with the effective user (group) id not equal to the
				11479	real user (group) id, and the <B>-p</B> option is not supplied, these actions
				11480	are taken and the effective user id is set to the real user id.
				11481	If the <B>-p</B> option is supplied at startup, the effective user id is
				11482	not reset.
				11483	Turning this option off causes the effective user
				11484	and group ids to be set to the real user and group ids.
				11485	<DT><B>-t</B>
				11486
				11487	<DD>
				11488	Exit after reading and executing one command.
				11489	<DT><B>-u</B>
				11490
				11491	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11492	Treat unset variables and parameters other than the special
				11493	parameters "@" and "*" as an error when performing
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11494	parameter expansion. If expansion is attempted on an
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11495	unset variable or parameter, the shell prints an error message, and,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11496	if not interactive, exits with a non-zero status.
				11497	<DT><B>-v</B>
				11498
				11499	<DD>
				11500	Print shell input lines as they are read.
				11501	<DT><B>-x</B>
				11502
				11503	<DD>
				11504	After expanding each <I>simple command</I>,
				11505	<B>for</B> command, <B>case</B> command, <B>select</B> command, or
				11506	arithmetic <B>for</B> command, display the expanded value of
				11507	<FONT SIZE=-1><B>PS4</B>,
				11508
				11509	</FONT>
				11510	followed by the command and its expanded arguments
				11511	or associated word list.
				11512	<DT><B>-B</B>
				11513
				11514	<DD>
				11515	The shell performs brace expansion (see
				11516	<B>Brace Expansion</B>
				11517
				11518	above). This is on by default.
				11519	<DT><B>-C</B>
				11520
				11521	<DD>
				11522	If set,
				11523	<B>bash</B>
				11524
				11525	does not overwrite an existing file with the
				11526	<B>></B>,
				11527
				11528	<B>>&</B>,
				11529
				11530	and
				11531	<B><></B>
				11532
				11533	redirection operators. This may be overridden when
				11534	creating output files by using the redirection operator
				11535	<B>>\|</B>
				11536
				11537	instead of
				11538	<B>></B>.
				11539
				11540	<DT><B>-E</B>
				11541
				11542	<DD>
				11543	If set, any trap on <B>ERR</B> is inherited by shell functions, command
				11544	substitutions, and commands executed in a subshell environment.
				11545	The <B>ERR</B> trap is normally not inherited in such cases.
				11546	<DT><B>-H</B>
				11547
				11548	<DD>
				11549	Enable
				11550	<B>!</B>
				11551
				11552	style history substitution. This option is on by
				11553	default when the shell is interactive.
				11554	<DT><B>-P</B>
				11555
				11556	<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11557	If set, the shell does not resolve symbolic links when executing
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11558	commands such as
				11559	<B>cd</B>
				11560
				11561	that change the current working directory. It uses the
				11562	physical directory structure instead. By default,
				11563	<B>bash</B>
				11564
				11565	follows the logical chain of directories when performing commands
				11566	which change the current directory.
				11567	<DT><B>-T</B>
				11568
				11569	<DD>
				11570	If set, any traps on <B>DEBUG</B> and <B>RETURN</B> are inherited by shell
				11571	functions, command substitutions, and commands executed in a
				11572	subshell environment.
				11573	The <B>DEBUG</B> and <B>RETURN</B> traps are normally not inherited
				11574	in such cases.
				11575	<DT><B>--</B>
				11576
				11577	<DD>
				11578	If no arguments follow this option, then the positional parameters are
				11579	unset. Otherwise, the positional parameters are set to the
				11580	<I>arg</I>s, even if some of them begin with a
				11581	<B>-</B>.
				11582
				11583	<DT><B>-</B>
				11584
				11585	<DD>
				11586	Signal the end of options, cause all remaining <I>arg</I>s to be
				11587	assigned to the positional parameters. The
				11588	<B>-x</B>
				11589
				11590	and
				11591	<B>-v</B>
				11592
				11593	options are turned off.
				11594	If there are no <I>arg</I>s,
				11595	the positional parameters remain unchanged.
				11596
				11597	</DL>
				11598	<P>
				11599
				11600	The options are off by default unless otherwise noted.
				11601	Using + rather than - causes these options to be turned off.
				11602	The options can also be specified as arguments to an invocation of
				11603	the shell.
				11604	The current set of options may be found in
				11605	<B>$-</B>.
				11606
				11607	The return status is always true unless an invalid option is encountered.
				11608	</DL>
				11609
				11610	<DT><B>shift</B> [<I>n</I>]<DD>
				11611	The positional parameters from <I>n</I>+1 ... are renamed to
				11612	<B>$1</B>
				11613
				11614	<B>....</B>
				11615
				11616	Parameters represented by the numbers <B>$#</B>
				11617	down to <B>$#</B>-<I>n</I>+1 are unset.
				11618	<I>n</I>
				11619
				11620	must be a non-negative number less than or equal to <B>$#</B>.
				11621	If
				11622	<I>n</I>
				11623
				11624	is 0, no parameters are changed.
				11625	If
				11626	<I>n </I>
				11627
				11628	is not given, it is assumed to be 1.
				11629	If
				11630	<I>n</I>
				11631
				11632	is greater than <B>$#</B>, the positional parameters are not changed.
				11633	The return status is greater than zero if
				11634	<I>n</I>
				11635
				11636	is greater than
				11637	<B>$#</B>
				11638
				11639	or less than zero; otherwise 0.
				11640	<DT><B>shopt</B> [<B>-pqsu</B>] [<B>-o</B>] [<I>optname</I> ...]<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11641	Toggle the values of settings controlling optional shell behavior.
				11642	The settings can be either those listed below, or, if the
				11643	<B>-o</B>
				11644
				11645	option is used, those available with the
				11646	<B>-o</B>
				11647
				11648	option to the <B>set</B> builtin command.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11649	With no options, or with the
				11650	<B>-p</B>
				11651
				11652	option, a list of all settable options is displayed, with
				11653	an indication of whether or not each is set.
				11654	The <B>-p</B> option causes output to be displayed in a form that
				11655	may be reused as input.
				11656	Other options have the following meanings:
				11657	<DL COMPACT><DT><DD>
				11658
				11659	<DL COMPACT>
				11660	<DT><B>-s</B>
				11661
				11662	<DD>
				11663	Enable (set) each <I>optname</I>.
				11664	<DT><B>-u</B>
				11665
				11666	<DD>
				11667	Disable (unset) each <I>optname</I>.
				11668	<DT><B>-q</B>
				11669
				11670	<DD>
				11671	Suppresses normal output (quiet mode); the return status indicates
				11672	whether the <I>optname</I> is set or unset.
				11673	If multiple <I>optname</I> arguments are given with
				11674	<B>-q</B>,
				11675
				11676	the return status is zero if all <I>optnames</I> are enabled; non-zero
				11677	otherwise.
				11678	<DT><B>-o</B>
				11679
				11680	<DD>
				11681	Restricts the values of <I>optname</I> to be those defined for the
				11682	<B>-o</B>
				11683
				11684	option to the
				11685	<B>set</B>
				11686
				11687	builtin.
				11688
				11689	</DL>
				11690	<P>
				11691
				11692	If either
				11693	<B>-s</B>
				11694
				11695	or
				11696	<B>-u</B>
				11697
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11698	is used with no <I>optname</I> arguments,
				11699	<B>shopt</B>
				11700
				11701	shows only those options which are set or unset, respectively.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11702	Unless otherwise noted, the <B>shopt</B> options are disabled (unset)
				11703	by default.
				11704	<P>
				11705
				11706	The return status when listing options is zero if all <I>optnames</I>
				11707	are enabled, non-zero otherwise. When setting or unsetting options,
				11708	the return status is zero unless an <I>optname</I> is not a valid shell
				11709	option.
				11710	<P>
				11711
				11712	The list of <B>shopt</B> options is:
				11713	<P>
				11714
				11715
				11716
				11717	<DL COMPACT>
				11718	<DT><B>autocd</B>
				11719
				11720	<DD>
				11721	If set, a command name that is the name of a directory is executed as if
				11722	it were the argument to the <B>cd</B> command.
				11723	This option is only used by interactive shells.
				11724	<DT><B>cdable_vars</B>
				11725
				11726	<DD>
				11727	If set, an argument to the
				11728	<B>cd</B>
				11729
				11730	builtin command that
				11731	is not a directory is assumed to be the name of a variable whose
				11732	value is the directory to change to.
				11733	<DT><B>cdspell</B>
				11734
				11735	<DD>
				11736	If set, minor errors in the spelling of a directory component in a
				11737	<B>cd</B>
				11738
				11739	command will be corrected.
				11740	The errors checked for are transposed characters,
				11741	a missing character, and one character too many.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11742	If a correction is found, the corrected filename is printed,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11743	and the command proceeds.
				11744	This option is only used by interactive shells.
				11745	<DT><B>checkhash</B>
				11746
				11747	<DD>
				11748	If set, <B>bash</B> checks that a command found in the hash
				11749	table exists before trying to execute it. If a hashed command no
				11750	longer exists, a normal path search is performed.
				11751	<DT><B>checkjobs</B>
				11752
				11753	<DD>
				11754	If set, <B>bash</B> lists the status of any stopped and running jobs before
				11755	exiting an interactive shell. If any jobs are running, this causes
				11756	the exit to be deferred until a second exit is attempted without an
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11757	intervening command (see
				11758	<FONT SIZE=-1><B>JOB CONTROL</B>
				11759
				11760	</FONT>
				11761	above). The shell always
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11762	postpones exiting if any jobs are stopped.
				11763	<DT><B>checkwinsize</B>
				11764
				11765	<DD>
				11766	If set, <B>bash</B> checks the window size after each command
				11767	and, if necessary, updates the values of
				11768	<FONT SIZE=-1><B>LINES</B>
				11769
				11770	</FONT>
				11771	and
				11772	<FONT SIZE=-1><B>COLUMNS</B>.
				11773
				11774	</FONT>
				11775	<DT><B>cmdhist</B>
				11776
				11777	<DD>
				11778	If set,
				11779	<B>bash</B>
				11780
				11781	attempts to save all lines of a multiple-line
				11782	command in the same history entry. This allows
				11783	easy re-editing of multi-line commands.
				11784	<DT><B>compat31</B>
				11785
				11786	<DD>
				11787	If set,
				11788	<B>bash</B>
				11789
				11790	changes its behavior to that of version 3.1 with respect to quoted
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11791	arguments to the <B>[[</B> conditional command's <B>=~</B> operator
				11792	and locale-specific string comparison when using the <B>[[</B>
				11793	conditional command's <B><</B> and <B>></B> operators.
				11794	Bash versions prior to bash-4.1 use ASCII collation and
				11795	<I>strcmp</I>(3);
				11796
				11797	bash-4.1 and later use the current locale's collation sequence and
				11798	<I>strcoll</I>(3).
				11799
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11800	<DT><B>compat32</B>
				11801
				11802	<DD>
				11803	If set,
				11804	<B>bash</B>
				11805
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11806	changes its behavior to that of version 3.2 with respect to
				11807	locale-specific string comparison when using the <B>[[</B>
				11808	conditional command's <B><</B> and <B>></B> operators (see previous item).
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11809	<DT><B>compat40</B>
				11810
				11811	<DD>
				11812	If set,
				11813	<B>bash</B>
				11814
				11815	changes its behavior to that of version 4.0 with respect to locale-specific
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	11816	string comparison when using the <B>[[</B>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11817	conditional command's <B><</B> and <B>></B> operators (see description of
				11818	<B>compat31</B>)
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11819	and the effect of interrupting a command list.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11820	Bash versions 4.0 and later interrupt the list as if the shell received the
				11821	interrupt; previous versions continue with the next command in the list.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	11822	<DT><B>compat41</B>
				11823
				11824	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	11825	If set,
				11826	<B>bash</B>,
				11827
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11828	when in <I>posix</I> mode, treats a single quote in a double-quoted
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	11829	parameter expansion as a special character. The single quotes must match
				11830	(an even number) and the characters between the single quotes are considered
				11831	quoted. This is the behavior of posix mode through version 4.1.
				11832	The default bash behavior remains as in previous versions.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11833	<DT><B>compat42</B>
				11834
				11835	<DD>
				11836	If set,
				11837	<B>bash</B>
				11838
				11839	does not process the replacement string in the pattern substitution word
				11840	expansion using quote removal.
				11841	<DT><B>complete_fullquote</B>
				11842
				11843	<DD>
				11844	If set,
				11845	<B>bash</B>
				11846
				11847	quotes all shell metacharacters in filenames and directory names when
				11848	performing completion.
				11849	If not set,
				11850	<B>bash</B>
				11851
				11852	removes metacharacters such as the dollar sign from the set of
				11853	characters that will be quoted in completed filenames
				11854	when these metacharacters appear in shell variable references in words to be
				11855	completed.
				11856	This means that dollar signs in variable names that expand to directories
				11857	will not be quoted;
				11858	however, any dollar signs appearing in filenames will not be quoted, either.
				11859	This is active only when bash is using backslashes to quote completed
				11860	filenames.
				11861	This variable is set by default, which is the default bash behavior in
				11862	versions through 4.2.
				11863	<DT><B>direxpand</B>
				11864
				11865	<DD>
				11866	If set,
				11867	<B>bash</B>
				11868
				11869	replaces directory names with the results of word expansion when performing
				11870	filename completion. This changes the contents of the readline editing
				11871	buffer.
				11872	If not set,
				11873	<B>bash</B>
				11874
				11875	attempts to preserve what the user typed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11876	<DT><B>dirspell</B>
				11877
				11878	<DD>
				11879	If set,
				11880	<B>bash</B>
				11881
				11882	attempts spelling correction on directory names during word completion
				11883	if the directory name initially supplied does not exist.
				11884	<DT><B>dotglob</B>
				11885
				11886	<DD>
				11887	If set,
				11888	<B>bash</B>
				11889
				11890	includes filenames beginning with a `.' in the results of pathname
				11891	expansion.
				11892	<DT><B>execfail</B>
				11893
				11894	<DD>
				11895	If set, a non-interactive shell will not exit if
				11896	it cannot execute the file specified as an argument to the
				11897	<B>exec</B>
				11898
				11899	builtin command. An interactive shell does not exit if
				11900	<B>exec</B>
				11901
				11902	fails.
				11903	<DT><B>expand_aliases</B>
				11904
				11905	<DD>
				11906	If set, aliases are expanded as described above under
				11907	<FONT SIZE=-1><B>ALIASES</B>.
				11908
				11909	</FONT>
				11910	This option is enabled by default for interactive shells.
				11911	<DT><B>extdebug</B>
				11912
				11913	<DD>
				11914	If set, behavior intended for use by debuggers is enabled:
				11915	<DL COMPACT><DT><DD>
				11916	<DL COMPACT>
				11917	<DT><B>1.</B>
				11918
				11919	<DD>
				11920	The <B>-F</B> option to the <B>declare</B> builtin displays the source
				11921	file name and line number corresponding to each function name supplied
				11922	as an argument.
				11923	<DT><B>2.</B>
				11924
				11925	<DD>
				11926	If the command run by the <B>DEBUG</B> trap returns a non-zero value, the
				11927	next command is skipped and not executed.
				11928	<DT><B>3.</B>
				11929
				11930	<DD>
				11931	If the command run by the <B>DEBUG</B> trap returns a value of 2, and the
				11932	shell is executing in a subroutine (a shell function or a shell script
				11933	executed by the <B>.</B> or <B>source</B> builtins), a call to
				11934	<B>return</B> is simulated.
				11935	<DT><B>4.</B>
				11936
				11937	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11938	<FONT SIZE=-1><B>BASH_ARGC</B>
				11939
				11940	</FONT>
				11941	and
				11942	<FONT SIZE=-1><B>BASH_ARGV</B>
				11943
				11944	</FONT>
				11945	are updated as described in their descriptions above.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11946	<DT><B>5.</B>
				11947
				11948	<DD>
				11949	Function tracing is enabled: command substitution, shell functions, and
				11950	subshells invoked with <B>(</B> <I>command</I> <B>)</B> inherit the
				11951	<B>DEBUG</B> and <B>RETURN</B> traps.
				11952	<DT><B>6.</B>
				11953
				11954	<DD>
				11955	Error tracing is enabled: command substitution, shell functions, and
				11956	subshells invoked with <B>(</B> <I>command</I> <B>)</B> inherit the
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	11957	<B>ERR</B> trap.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11958	</DL></DL>
				11959
				11960	<DT><B>extglob</B>
				11961
				11962	<DD>
				11963	If set, the extended pattern matching features described above under
				11964	<B>Pathname Expansion</B> are enabled.
				11965	<DT><B>extquote</B>
				11966
				11967	<DD>
				11968	If set, <B>$</B>aq<I>string</I>aq and <B>$</B>"<I>string</I>" quoting is
				11969	performed within <B>${</B><I>parameter</I><B>}</B> expansions
				11970	enclosed in double quotes. This option is enabled by default.
				11971	<DT><B>failglob</B>
				11972
				11973	<DD>
				11974	If set, patterns which fail to match filenames during pathname expansion
				11975	result in an expansion error.
				11976	<DT><B>force_fignore</B>
				11977
				11978	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11979	If set, the suffixes specified by the
				11980	<FONT SIZE=-1><B>FIGNORE</B>
				11981
				11982	</FONT>
				11983	shell variable
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11984	cause words to be ignored when performing word completion even if
				11985	the ignored words are the only possible completions.
				11986	See
				11987	<FONT SIZE=-1><B>SHELL VARIABLES</B></FONT>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	11988	above for a description of
				11989	<FONT SIZE=-1><B>FIGNORE</B>.
				11990
				11991	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	11992	This option is enabled by default.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	11993	<DT><B>globasciiranges</B>
				11994
				11995	<DD>
				11996	If set, range expressions used in pattern matching bracket expressions (see
				11997	<FONT SIZE=-1><B>Pattern Matching</B>
				11998
				11999	</FONT>
				12000	above) behave as if in the traditional C locale when performing
				12001	comparisons. That is, the current locale's collating sequence
				12002	is not taken into account, so
				12003	<B>b</B>
				12004
				12005	will not collate between
				12006	<B>A</B>
				12007
				12008	and
				12009	<B>B</B>,
				12010
				12011	and upper-case and lower-case ASCII characters will collate together.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12012	<DT><B>globstar</B>
				12013
				12014	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12015	If set, the pattern <B>**</B> used in a pathname expansion context will
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12016	match all files and zero or more directories and subdirectories.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12017	If the pattern is followed by a <B>/</B>, only directories and
				12018	subdirectories match.
				12019	<DT><B>gnu_errfmt</B>
				12020
				12021	<DD>
				12022	If set, shell error messages are written in the standard GNU error
				12023	message format.
				12024	<DT><B>histappend</B>
				12025
				12026	<DD>
				12027	If set, the history list is appended to the file named by the value
				12028	of the
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12029	<FONT SIZE=-1><B>HISTFILE</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12030
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12031	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12032	variable when the shell exits, rather than overwriting the file.
				12033	<DT><B>histreedit</B>
				12034
				12035	<DD>
				12036	If set, and
				12037	<B>readline</B>
				12038
				12039	is being used, a user is given the opportunity to re-edit a
				12040	failed history substitution.
				12041	<DT><B>histverify</B>
				12042
				12043	<DD>
				12044	If set, and
				12045	<B>readline</B>
				12046
				12047	is being used, the results of history substitution are not immediately
				12048	passed to the shell parser. Instead, the resulting line is loaded into
				12049	the <B>readline</B> editing buffer, allowing further modification.
				12050	<DT><B>hostcomplete</B>
				12051
				12052	<DD>
				12053	If set, and
				12054	<B>readline</B>
				12055
				12056	is being used, <B>bash</B> will attempt to perform hostname completion when a
				12057	word containing a <B>@</B> is being completed (see
				12058	<B>Completing</B>
				12059
				12060	under
				12061	<FONT SIZE=-1><B>READLINE</B>
				12062
				12063	</FONT>
				12064	above).
				12065	This is enabled by default.
				12066	<DT><B>huponexit</B>
				12067
				12068	<DD>
				12069	If set, <B>bash</B> will send
				12070	<FONT SIZE=-1><B>SIGHUP</B>
				12071
				12072	</FONT>
				12073	to all jobs when an interactive login shell exits.
				12074	<DT><B>interactive_comments</B>
				12075
				12076	<DD>
				12077	If set, allow a word beginning with
				12078	<B>#</B>
				12079
				12080	to cause that word and all remaining characters on that
				12081	line to be ignored in an interactive shell (see
				12082	<FONT SIZE=-1><B>COMMENTS</B>
				12083
				12084	</FONT>
				12085	above). This option is enabled by default.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12086	<DT><B>lastpipe</B>
				12087
				12088	<DD>
				12089	If set, and job control is not active, the shell runs the last command of
				12090	a pipeline not executed in the background in the current shell environment.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12091	<DT><B>lithist</B>
				12092
				12093	<DD>
				12094	If set, and the
				12095	<B>cmdhist</B>
				12096
				12097	option is enabled, multi-line commands are saved to the history with
				12098	embedded newlines rather than using semicolon separators where possible.
				12099	<DT><B>login_shell</B>
				12100
				12101	<DD>
				12102	The shell sets this option if it is started as a login shell (see
				12103	<FONT SIZE=-1><B>INVOCATION</B>
				12104
				12105	</FONT>
				12106	above).
				12107	The value may not be changed.
				12108	<DT><B>mailwarn</B>
				12109
				12110	<DD>
				12111	If set, and a file that <B>bash</B> is checking for mail has been
				12112	accessed since the last time it was checked, the message ``The mail in
				12113	<I>mailfile</I> has been read'' is displayed.
				12114	<DT><B>no_empty_cmd_completion</B>
				12115
				12116	<DD>
				12117	If set, and
				12118	<B>readline</B>
				12119
				12120	is being used,
				12121	<B>bash</B>
				12122
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12123	will not attempt to search the
				12124	<FONT SIZE=-1><B>PATH</B>
				12125
				12126	</FONT>
				12127	for possible completions when
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12128	completion is attempted on an empty line.
				12129	<DT><B>nocaseglob</B>
				12130
				12131	<DD>
				12132	If set,
				12133	<B>bash</B>
				12134
				12135	matches filenames in a case-insensitive fashion when performing pathname
				12136	expansion (see
				12137	<B>Pathname Expansion</B>
				12138
				12139	above).
				12140	<DT><B>nocasematch</B>
				12141
				12142	<DD>
				12143	If set,
				12144	<B>bash</B>
				12145
				12146	matches patterns in a case-insensitive fashion when performing matching
				12147	while executing <B>case</B> or <B>[[</B> conditional commands.
				12148	<DT><B>nullglob</B>
				12149
				12150	<DD>
				12151	If set,
				12152	<B>bash</B>
				12153
				12154	allows patterns which match no
				12155	files (see
				12156	<B>Pathname Expansion</B>
				12157
				12158	above)
				12159	to expand to a null string, rather than themselves.
				12160	<DT><B>progcomp</B>
				12161
				12162	<DD>
				12163	If set, the programmable completion facilities (see
				12164	<B>Programmable Completion</B> above) are enabled.
				12165	This option is enabled by default.
				12166	<DT><B>promptvars</B>
				12167
				12168	<DD>
				12169	If set, prompt strings undergo
				12170	parameter expansion, command substitution, arithmetic
				12171	expansion, and quote removal after being expanded as described in
				12172	<FONT SIZE=-1><B>PROMPTING</B>
				12173
				12174	</FONT>
				12175	above. This option is enabled by default.
				12176	<DT><B>restricted_shell</B>
				12177
				12178	<DD>
				12179	The shell sets this option if it is started in restricted mode (see
				12180	<FONT SIZE=-1><B>RESTRICTED SHELL</B>
				12181
				12182	</FONT>
				12183	below).
				12184	The value may not be changed.
				12185	This is not reset when the startup files are executed, allowing
				12186	the startup files to discover whether or not a shell is restricted.
				12187	<DT><B>shift_verbose</B>
				12188
				12189	<DD>
				12190	If set, the
				12191	<B>shift</B>
				12192
				12193	builtin prints an error message when the shift count exceeds the
				12194	number of positional parameters.
				12195	<DT><B>sourcepath</B>
				12196
				12197	<DD>
				12198	If set, the
				12199	<B>source</B> (<B>.</B>) builtin uses the value of
				12200	<FONT SIZE=-1><B>PATH</B>
				12201
				12202	</FONT>
				12203	to find the directory containing the file supplied as an argument.
				12204	This option is enabled by default.
				12205	<DT><B>xpg_echo</B>
				12206
				12207	<DD>
				12208	If set, the <B>echo</B> builtin expands backslash-escape sequences
				12209	by default.
				12210	</DL></DL>
				12211
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12212
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12213	<DT><B>suspend</B> [<B>-f</B>]<DD>
				12214	Suspend the execution of this shell until it receives a
				12215	<FONT SIZE=-1><B>SIGCONT</B>
				12216
				12217	</FONT>
				12218	signal. A login shell cannot be suspended; the
				12219	<B>-f</B>
				12220
				12221	option can be used to override this and force the suspension.
				12222	The return status is 0 unless the shell is a login shell and
				12223	<B>-f</B>
				12224
				12225	is not supplied, or if job control is not enabled.
				12226	<DT><B>test</B> <I>expr</I><DD>
				12227
				12228	<DT><B>[</B> <I>expr</I> <B>]</B><DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12229	Return a status of 0 (true) or 1 (false) depending on
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12230	the evaluation of the conditional expression
				12231	<I>expr</I>.
				12232
				12233	Each operator and operand must be a separate argument.
				12234	Expressions are composed of the primaries described above under
				12235	<FONT SIZE=-1><B>CONDITIONAL EXPRESSIONS</B>.
				12236
				12237	</FONT>
				12238	<B>test</B> does not accept any options, nor does it accept and ignore
				12239	an argument of <B>--</B> as signifying the end of options.
				12240	<P>
				12241
				12242
				12243	Expressions may be combined using the following operators, listed
				12244	in decreasing order of precedence.
				12245	The evaluation depends on the number of arguments; see below.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12246	Operator precedence is used when there are five or more arguments.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12247	<DL COMPACT><DT><DD>
				12248
				12249	<DL COMPACT>
				12250	<DT><B>! </B><I>expr</I>
				12251
				12252	<DD>
				12253	True if
				12254	<I>expr</I>
				12255
				12256	is false.
				12257	<DT><B>( </B><I>expr</I> )
				12258
				12259	<DD>
				12260	Returns the value of <I>expr</I>.
				12261	This may be used to override the normal precedence of operators.
				12262	<DT><I>expr1</I> -<B>a</B> <I>expr2</I><DD>
				12263	True if both
				12264	<I>expr1</I>
				12265
				12266	and
				12267	<I>expr2</I>
				12268
				12269	are true.
				12270	<DT><I>expr1</I> -<B>o</B> <I>expr2</I><DD>
				12271	True if either
				12272	<I>expr1</I>
				12273
				12274	or
				12275	<I>expr2</I>
				12276
				12277	is true.
				12278
				12279	</DL>
				12280	<P>
				12281
				12282	<B>test</B> and <B>[</B> evaluate conditional
				12283	expressions using a set of rules based on the number of arguments.
				12284	<P>
				12285
				12286
				12287
				12288	<DL COMPACT>
				12289	<DT>0 arguments<DD>
				12290	The expression is false.
				12291	<DT>1 argument<DD>
				12292	The expression is true if and only if the argument is not null.
				12293	<DT>2 arguments<DD>
				12294	If the first argument is <B>!</B>, the expression is true if and
				12295	only if the second argument is null.
				12296	If the first argument is one of the unary conditional operators listed above
				12297	under
				12298	<FONT SIZE=-1><B>CONDITIONAL EXPRESSIONS</B>,
				12299
				12300	</FONT>
				12301	the expression is true if the unary test is true.
				12302	If the first argument is not a valid unary conditional operator, the expression
				12303	is false.
				12304	<DT>3 arguments<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12305	The following conditions are applied in the order listed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12306	If the second argument is one of the binary conditional operators listed above
				12307	under
				12308	<FONT SIZE=-1><B>CONDITIONAL EXPRESSIONS</B>,
				12309
				12310	</FONT>
				12311	the result of the expression is the result of the binary test using
				12312	the first and third arguments as operands.
				12313	The <B>-a</B> and <B>-o</B> operators are considered binary operators
				12314	when there are three arguments.
				12315	If the first argument is <B>!</B>, the value is the negation of
				12316	the two-argument test using the second and third arguments.
				12317	If the first argument is exactly <B>(</B> and the third argument is
				12318	exactly <B>)</B>, the result is the one-argument test of the second
				12319	argument.
				12320	Otherwise, the expression is false.
				12321	<DT>4 arguments<DD>
				12322	If the first argument is <B>!</B>, the result is the negation of
				12323	the three-argument expression composed of the remaining arguments.
				12324	Otherwise, the expression is parsed and evaluated according to
				12325	precedence using the rules listed above.
				12326	<DT>5 or more arguments<DD>
				12327	The expression is parsed and evaluated according to precedence
				12328	using the rules listed above.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12329	<P>
				12330
				12331
				12332	</DL>
				12333	<P>
				12334
				12335	When used with <B>test</B> or <B>[</B>, the <B><</B> and <B>></B> operators
				12336	sort lexicographically using ASCII ordering.
				12337	</DL>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12338
				12339
				12340	<DT><B>times</B>
				12341
				12342	<DD>
				12343	Print the accumulated user and system times for the shell and
				12344	for processes run from the shell. The return status is 0.
				12345	<DT><B>trap</B> [<B>-lp</B>] [[<I>arg</I>] <I>sigspec</I> ...]<DD>
				12346	The command
				12347	<I>arg</I>
				12348
				12349	is to be read and executed when the shell receives
				12350	signal(s)
				12351	<I>sigspec</I>.
				12352
				12353	If
				12354	<I>arg</I>
				12355
				12356	is absent (and there is a single <I>sigspec</I>) or
				12357	<B>-</B>,
				12358
				12359	each specified signal is
				12360	reset to its original disposition (the value it had
				12361	upon entrance to the shell).
				12362	If
				12363	<I>arg</I>
				12364
				12365	is the null string the signal specified by each
				12366	<I>sigspec</I>
				12367
				12368	is ignored by the shell and by the commands it invokes.
				12369	If
				12370	<I>arg</I>
				12371
				12372	is not present and
				12373	<B>-p</B>
				12374
				12375	has been supplied, then the trap commands associated with each
				12376	<I>sigspec</I>
				12377
				12378	are displayed.
				12379	If no arguments are supplied or if only
				12380	<B>-p</B>
				12381
				12382	is given,
				12383	<B>trap</B>
				12384
				12385	prints the list of commands associated with each signal.
				12386	The
				12387	<B>-l</B>
				12388
				12389	option causes the shell to print a list of signal names and
				12390	their corresponding numbers.
				12391	Each
				12392	<I>sigspec</I>
				12393
				12394	is either
				12395	a signal name defined in <<I>signal.h</I>>, or a signal number.
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12396	Signal names are case insensitive and the
				12397	<FONT SIZE=-1><B>SIG</B>
				12398
				12399	</FONT>
				12400	prefix is optional.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12401	<P>
				12402
				12403
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12404	If a
				12405	<I>sigspec</I>
				12406
				12407	is
				12408	<FONT SIZE=-1><B>EXIT</B>
				12409
				12410	</FONT>
				12411	(0) the command
				12412	<I>arg</I>
				12413
				12414	is executed on exit from the shell.
				12415	If a
				12416	<I>sigspec</I>
				12417
				12418	is
				12419	<FONT SIZE=-1><B>DEBUG</B>,
				12420
				12421	</FONT>
				12422	the command
				12423	<I>arg</I>
				12424
				12425	is executed before every <I>simple command</I>, <I>for</I> command,
				12426	<I>case</I> command, <I>select</I> command, every arithmetic <I>for</I>
				12427	command, and before the first command executes in a shell function (see
				12428	<FONT SIZE=-1><B>SHELL GRAMMAR</B>
				12429
				12430	</FONT>
				12431	above).
				12432	Refer to the description of the <B>extdebug</B> option to the
				12433	<B>shopt</B> builtin for details of its effect on the <B>DEBUG</B> trap.
				12434	If a
				12435	<I>sigspec</I>
				12436
				12437	is
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12438	<FONT SIZE=-1><B>RETURN</B>,
				12439
				12440	</FONT>
				12441	the command
				12442	<I>arg</I>
				12443
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12444	is executed each time a shell function or a script executed with
				12445	the <B>.</B> or <B>source</B> builtins finishes executing.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12446	<P>
				12447
				12448
				12449	If a
				12450	<I>sigspec</I>
				12451
				12452	is
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12453	<FONT SIZE=-1><B>ERR</B>,
				12454
				12455	</FONT>
				12456	the command
				12457	<I>arg</I>
				12458
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12459	is executed whenever a
				12460	a pipeline (which may consist of a single simple
				12461	command), a list, or a compound command returns a
				12462	non-zero exit status,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12463	subject to the following conditions.
				12464	The
				12465	<FONT SIZE=-1><B>ERR</B>
				12466
				12467	</FONT>
				12468	trap is not executed if the failed
				12469	command is part of the command list immediately following a
				12470	<B>while</B>
				12471
				12472	or
				12473	<B>until</B>
				12474
				12475	keyword,
				12476	part of the test in an
				12477	<I>if</I>
				12478
				12479	statement, part of a command executed in a
				12480	<B>&&</B>
				12481
				12482	or
				12483	<B>\|\|</B>
				12484
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12485	list except the command following the final <B>&&</B> or <B>\|\|</B>,
				12486	any command in a pipeline but the last,
				12487	or if the command's return value is
				12488	being inverted using
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12489	<B>!</B>.
				12490
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12491	These are the same conditions obeyed by the <B>errexit</B> (<B>-e</B>) option.
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12492	<P>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12493
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12494
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12495	Signals ignored upon entry to the shell cannot be trapped or reset.
				12496	Trapped signals that are not being ignored are reset to their original
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12497	values in a subshell or subshell environment when one is created.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12498	The return status is false if any
				12499	<I>sigspec</I>
				12500
				12501	is invalid; otherwise
				12502	<B>trap</B>
				12503
				12504	returns true.
				12505	<DT><B>type</B> [<B>-aftpP</B>] <I>name</I> [<I>name</I> ...]<DD>
				12506	With no options,
				12507	indicate how each
				12508	<I>name</I>
				12509
				12510	would be interpreted if used as a command name.
				12511	If the
				12512	<B>-t</B>
				12513
				12514	option is used,
				12515	<B>type</B>
				12516
				12517	prints a string which is one of
				12518	<I>alias</I>,
				12519
				12520	<I>keyword</I>,
				12521
				12522	<I>function</I>,
				12523
				12524	<I>builtin</I>,
				12525
				12526	or
				12527	<I>file </I>
				12528
				12529	if
				12530	<I>name</I>
				12531
				12532	is an alias, shell reserved word, function, builtin, or disk file,
				12533	respectively.
				12534	If the
				12535	<I>name</I>
				12536
				12537	is not found, then nothing is printed, and an exit status of false
				12538	is returned.
				12539	If the
				12540	<B>-p</B>
				12541
				12542	option is used,
				12543	<B>type</B>
				12544
				12545	either returns the name of the disk file
				12546	that would be executed if
				12547	<I>name</I>
				12548
				12549	were specified as a command name,
				12550	or nothing if
				12551	<TT>type -t name</TT>
				12552
				12553	would not return
				12554	<I>file</I>.
				12555
				12556	The
				12557	<B>-P</B>
				12558
				12559	option forces a
				12560	<FONT SIZE=-1><B>PATH</B>
				12561
				12562	</FONT>
				12563	search for each <I>name</I>, even if
				12564	<TT>type -t name</TT>
				12565
				12566	would not return
				12567	<I>file</I>.
				12568
				12569	If a command is hashed,
				12570	<B>-p</B>
				12571
				12572	and
				12573	<B>-P</B>
				12574
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12575	print the hashed value, which is not necessarily the file that appears
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12576	first in
				12577	<FONT SIZE=-1><B>PATH</B>.
				12578
				12579	</FONT>
				12580	If the
				12581	<B>-a</B>
				12582
				12583	option is used,
				12584	<B>type</B>
				12585
				12586	prints all of the places that contain
				12587	an executable named
				12588	<I>name</I>.
				12589
				12590	This includes aliases and functions,
				12591	if and only if the
				12592	<B>-p</B>
				12593
				12594	option is not also used.
				12595	The table of hashed commands is not consulted
				12596	when using
				12597	<B>-a</B>.
				12598
				12599	The
				12600	<B>-f</B>
				12601
				12602	option suppresses shell function lookup, as with the <B>command</B> builtin.
				12603	<B>type</B>
				12604
				12605	returns true if all of the arguments are found, false if
				12606	any are not found.
				12607	<DT><B>ulimit</B> [<B>-HSTabcdefilmnpqrstuvx</B> [<I>limit</I>]]<DD>
				12608	Provides control over the resources available to the shell and to
				12609	processes started by it, on systems that allow such control.
				12610	The <B>-H</B> and <B>-S</B> options specify that the hard or soft limit is
				12611	set for the given resource.
				12612	A hard limit cannot be increased by a non-root user once it is set;
				12613	a soft limit may be increased up to the value of the hard limit.
				12614	If neither <B>-H</B> nor <B>-S</B> is specified, both the soft and hard
				12615	limits are set.
				12616	The value of
				12617	<I>limit</I>
				12618
				12619	can be a number in the unit specified for the resource
				12620	or one of the special values
				12621	<B>hard</B>,
				12622
				12623	<B>soft</B>,
				12624
				12625	or
				12626	<B>unlimited</B>,
				12627
				12628	which stand for the current hard limit, the current soft limit, and
				12629	no limit, respectively.
				12630	If
				12631	<I>limit</I>
				12632
				12633	is omitted, the current value of the soft limit of the resource is
				12634	printed, unless the <B>-H</B> option is given. When more than one
				12635	resource is specified, the limit name and unit are printed before the value.
				12636	Other options are interpreted as follows:
				12637	<DL COMPACT><DT><DD>
				12638
				12639	<DL COMPACT>
				12640	<DT><B>-a</B>
				12641
				12642	<DD>
				12643	All current limits are reported
				12644	<DT><B>-b</B>
				12645
				12646	<DD>
				12647	The maximum socket buffer size
				12648	<DT><B>-c</B>
				12649
				12650	<DD>
				12651	The maximum size of core files created
				12652	<DT><B>-d</B>
				12653
				12654	<DD>
				12655	The maximum size of a process's data segment
				12656	<DT><B>-e</B>
				12657
				12658	<DD>
				12659	The maximum scheduling priority ("nice")
				12660	<DT><B>-f</B>
				12661
				12662	<DD>
				12663	The maximum size of files written by the shell and its children
				12664	<DT><B>-i</B>
				12665
				12666	<DD>
				12667	The maximum number of pending signals
				12668	<DT><B>-l</B>
				12669
				12670	<DD>
				12671	The maximum size that may be locked into memory
				12672	<DT><B>-m</B>
				12673
				12674	<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12675	The maximum resident set size (many systems do not honor this limit)
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12676	<DT><B>-n</B>
				12677
				12678	<DD>
				12679	The maximum number of open file descriptors (most systems do not
				12680	allow this value to be set)
				12681	<DT><B>-p</B>
				12682
				12683	<DD>
				12684	The pipe size in 512-byte blocks (this may not be set)
				12685	<DT><B>-q</B>
				12686
				12687	<DD>
				12688	The maximum number of bytes in POSIX message queues
				12689	<DT><B>-r</B>
				12690
				12691	<DD>
				12692	The maximum real-time scheduling priority
				12693	<DT><B>-s</B>
				12694
				12695	<DD>
				12696	The maximum stack size
				12697	<DT><B>-t</B>
				12698
				12699	<DD>
				12700	The maximum amount of cpu time in seconds
				12701	<DT><B>-u</B>
				12702
				12703	<DD>
				12704	The maximum number of processes available to a single user
				12705	<DT><B>-v</B>
				12706
				12707	<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12708	The maximum amount of virtual memory available to the shell and, on
				12709	some systems, to its children
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12710	<DT><B>-x</B>
				12711
				12712	<DD>
				12713	The maximum number of file locks
				12714	<DT><B>-T</B>
				12715
				12716	<DD>
				12717	The maximum number of threads
				12718
				12719	</DL>
				12720	<P>
				12721
				12722	If
				12723	<I>limit</I>
				12724
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12725	is given, and the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12726	<B>-a</B>
				12727
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12728	option is not used,
				12729	<I>limit</I> is the new value of the specified resource.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12730	If no option is given, then
				12731	<B>-f</B>
				12732
				12733	is assumed. Values are in 1024-byte increments, except for
				12734	<B>-t</B>,
				12735
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12736	which is in seconds;
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12737	<B>-p</B>,
				12738
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12739	which is in units of 512-byte blocks;
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12740	and
				12741	<B>-T</B>,
				12742
				12743	<B>-b</B>,
				12744
				12745	<B>-n</B>,
				12746
				12747	and
				12748	<B>-u</B>,
				12749
				12750	which are unscaled values.
				12751	The return status is 0 unless an invalid option or argument is supplied,
				12752	or an error occurs while setting a new limit.
				12753	</DL>
				12754
				12755	<DT><B>umask</B> [<B>-p</B>] [<B>-S</B>] [<I>mode</I>]<DD>
				12756	The user file-creation mask is set to
				12757	<I>mode</I>.
				12758
				12759	If
				12760	<I>mode</I>
				12761
				12762	begins with a digit, it
				12763	is interpreted as an octal number; otherwise
				12764	it is interpreted as a symbolic mode mask similar
				12765	to that accepted by
				12766	<I>chmod</I>(1).
				12767
				12768	If
				12769	<I>mode</I>
				12770
				12771	is omitted, the current value of the mask is printed.
				12772	The
				12773	<B>-S</B>
				12774
				12775	option causes the mask to be printed in symbolic form; the
				12776	default output is an octal number.
				12777	If the
				12778	<B>-p</B>
				12779
				12780	option is supplied, and
				12781	<I>mode</I>
				12782
				12783	is omitted, the output is in a form that may be reused as input.
				12784	The return status is 0 if the mode was successfully changed or if
				12785	no <I>mode</I> argument was supplied, and false otherwise.
				12786	<DT><B>unalias</B> [-<B>a</B>] [<I>name</I> ...]<DD>
				12787	Remove each <I>name</I> from the list of defined aliases. If
				12788	<B>-a</B>
				12789
				12790	is supplied, all alias definitions are removed. The return
				12791	value is true unless a supplied
				12792	<I>name</I>
				12793
				12794	is not a defined alias.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12795	<DT><B>unset</B> [-<B>fv</B>] [-<B>n</B>] [<I>name</I> ...]<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12796	For each
				12797	<I>name</I>,
				12798
				12799	remove the corresponding variable or function.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12800	If the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12801	<B>-v</B>
				12802
				12803	option is given, each
				12804	<I>name</I>
				12805
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12806	refers to a shell variable, and that variable is removed.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12807	Read-only variables may not be unset.
				12808	If
				12809	<B>-f</B>
				12810
				12811	is specified, each
				12812	<I>name</I>
				12813
				12814	refers to a shell function, and the function definition
				12815	is removed.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12816	If the
				12817	<B>-n</B>
				12818
				12819	option is supplied, and <I>name</I> is a variable with the <I>nameref</I>
				12820	attribute, <I>name</I> will be unset rather than the variable it
				12821	references.
				12822	<B>-n</B> has no effect if the <B>-f</B> option is supplied.
				12823	If no options are supplied, each <I>name</I> refers to a variable; if
				12824	there is no variable by that name, any function with that name is
				12825	unset.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12826	Each unset variable or function is removed from the environment
				12827	passed to subsequent commands.
				12828	If any of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12829	<FONT SIZE=-1><B>COMP_WORDBREAKS</B>,
				12830
				12831	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12832	<FONT SIZE=-1><B>RANDOM</B>,
				12833
				12834	</FONT>
				12835	<FONT SIZE=-1><B>SECONDS</B>,
				12836
				12837	</FONT>
				12838	<FONT SIZE=-1><B>LINENO</B>,
				12839
				12840	</FONT>
				12841	<FONT SIZE=-1><B>HISTCMD</B>,
				12842
				12843	</FONT>
				12844	<FONT SIZE=-1><B>FUNCNAME</B>,
				12845
				12846	</FONT>
				12847	<FONT SIZE=-1><B>GROUPS</B>,
				12848
				12849	</FONT>
				12850	or
				12851	<FONT SIZE=-1><B>DIRSTACK</B>
				12852
				12853	</FONT>
				12854	are unset, they lose their special properties, even if they are
				12855	subsequently reset. The exit status is true unless a
				12856	<I>name</I>
				12857
				12858	is readonly.
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12859	<DT><B>wait</B> [<B>-n</B>] [<I>n ...</I>]<DD>
				12860	Wait for each specified child process and return its termination status.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12861	Each
				12862	<I>n</I>
				12863
				12864	may be a process
				12865	ID or a job specification; if a job spec is given, all processes
				12866	in that job's pipeline are waited for. If
				12867	<I>n</I>
				12868
				12869	is not given, all currently active child processes
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12870	are waited for, and the return status is zero.
				12871	If the <B>-n</B> option is supplied, <B>wait</B> waits for any job to
				12872	terminate and returns its exit status.
				12873	If
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12874	<I>n</I>
				12875
				12876	specifies a non-existent process or job, the return status is
				12877	127. Otherwise, the return status is the exit status of the last
				12878	process or job waited for.
				12879
				12880
				12881	</DL>
				12882	<A NAME="lbDC"> </A>
				12883	<H3>RESTRICTED SHELL</H3>
				12884
				12885
				12886
				12887	<P>
				12888
				12889	If
				12890	<B>bash</B>
				12891
				12892	is started with the name
				12893	<B>rbash</B>,
				12894
				12895	or the
				12896	<B>-r</B>
				12897
				12898	option is supplied at invocation,
				12899	the shell becomes restricted.
				12900	A restricted shell is used to
				12901	set up an environment more controlled than the standard shell.
				12902	It behaves identically to
				12903	<B>bash</B>
				12904
				12905	with the exception that the following are disallowed or not performed:
				12906	<DL COMPACT>
				12907	<DT>*<DD>
				12908	changing directories with <B>cd</B>
				12909	<DT>*<DD>
				12910	setting or unsetting the values of
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12911	<FONT SIZE=-1><B>SHELL</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12912
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12913	</FONT>
				12914	<FONT SIZE=-1><B>PATH</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12915
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12916	</FONT>
				12917	<FONT SIZE=-1><B>ENV</B>,
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12918
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12919	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12920	or
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12921	<FONT SIZE=-1><B>BASH_ENV</B>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12922
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12923	</FONT>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12924	<DT>*<DD>
				12925	specifying command names containing
				12926	<B>/</B>
				12927
				12928	<DT>*<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	12929	specifying a filename containing a
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12930	<B>/</B>
				12931
				12932	as an argument to the
				12933	<B>.</B>
				12934
				12935	builtin command
				12936	<DT>*<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12937	specifying a filename containing a slash as an argument to the
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12938	<B>-p</B>
				12939
				12940	option to the
				12941	<B>hash</B>
				12942
				12943	builtin command
				12944	<DT>*<DD>
				12945	importing function definitions from the shell environment at startup
				12946	<DT>*<DD>
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	12947	parsing the value of
				12948	<FONT SIZE=-1><B>SHELLOPTS</B>
				12949
				12950	</FONT>
				12951	from the shell environment at startup
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12952	<DT>*<DD>
				12953	redirecting output using the >, >\|, <>, >&, &>, and >> redirection operators
				12954	<DT>*<DD>
				12955	using the
				12956	<B>exec</B>
				12957
				12958	builtin command to replace the shell with another command
				12959	<DT>*<DD>
				12960	adding or deleting builtin commands with the
				12961	<B>-f</B>
				12962
				12963	and
				12964	<B>-d</B>
				12965
				12966	options to the
				12967	<B>enable</B>
				12968
				12969	builtin command
				12970	<DT>*<DD>
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	12971	using the <B>enable</B> builtin command to enable disabled shell builtins
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	12972	<DT>*<DD>
				12973	specifying the
				12974	<B>-p</B>
				12975
				12976	option to the
				12977	<B>command</B>
				12978
				12979	builtin command
				12980	<DT>*<DD>
				12981	turning off restricted mode with
				12982	<B>set +r</B> or <B>set +o restricted</B>.
				12983	</DL>
				12984	<P>
				12985
				12986	These restrictions are enforced after any startup files are read.
				12987	<P>
				12988
				12989
				12990	When a command that is found to be a shell script is executed
				12991	(see
				12992	<FONT SIZE=-1><B>COMMAND EXECUTION</B>
				12993
				12994	</FONT>
				12995
				12996	above),
				12997
				12998	<B>rbash</B>
				12999
				13000	turns off any restrictions in the shell spawned to execute the
				13001	script.
				13002
				13003
				13004	<A NAME="lbDD"> </A>
				13005	<H3>SEE ALSO</H3>
				13006
				13007
				13008	<DL COMPACT>
				13009	<DT><I>Bash Reference Manual</I>, Brian Fox and Chet Ramey<DD>
				13010	<DT><I>The Gnu Readline Library</I>, Brian Fox and Chet Ramey<DD>
				13011	<DT><I>The Gnu History Library</I>, Brian Fox and Chet Ramey<DD>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	13012	<DT><I>Portable Operating System Interface (POSIX) Part 2: Shell and Utilities</I>, IEEE --<DD>
				13013	<A HREF="http://pubs.opengroup.org/onlinepubs/9699919799/">http://pubs.opengroup.org/onlinepubs/9699919799/</A>
				13014	<DT><A HREF="http://tiswww.case.edu/~chet/bash/POSIX">http://tiswww.case.edu/~chet/bash/POSIX</A> -- a description of posix mode<DD>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	13015	<DT><I>sh</I>(1), <I>ksh</I>(1), <I>csh</I>(1)<DD>
				13016	<DT><I>emacs</I>(1), <I>vi</I>(1)<DD>
				13017	<DT><I>readline</I>(3)<DD>
				13018
				13019	</DL>
				13020	<A NAME="lbDE"> </A>
				13021	<H3>FILES</H3>
				13022
				13023
				13024	<DL COMPACT>
				13025	<DT>
				13026	<A HREF="file:/bin/bash"><I>/bin/bash</I></A>
				13027
				13028	<DD>
				13029	The <B>bash</B> executable
				13030	<DT>
				13031	<A HREF="file:/etc/profile"><I>/etc/profile</I></A>
				13032
				13033	<DD>
				13034	The systemwide initialization file, executed for login shells
				13035	<DT>
				13036	<A HREF="file:~/.bash_profile"><I>~/.bash_profile</I></A>
				13037
				13038	<DD>
				13039	The personal initialization file, executed for login shells
				13040	<DT>
				13041	<A HREF="file:~/.bashrc"><I>~/.bashrc</I></A>
				13042
				13043	<DD>
				13044	The individual per-interactive-shell startup file
				13045	<DT>
				13046	<A HREF="file:~/.bash_logout"><I>~/.bash_logout</I></A>
				13047
				13048	<DD>
				13049	The individual login shell cleanup file, executed when a login shell exits
				13050	<DT>
				13051	<A HREF="file:~/.inputrc"><I>~/.inputrc</I></A>
				13052
				13053	<DD>
				13054	Individual <I>readline</I> initialization file
				13055
				13056	</DL>
				13057	<A NAME="lbDF"> </A>
				13058	<H3>AUTHORS</H3>
				13059
				13060	Brian Fox, Free Software Foundation
				13061	<BR>
				13062
				13063	<A HREF="mailto:bfox@gnu.org">bfox@gnu.org</A>
				13064	<P>
				13065
				13066	Chet Ramey, Case Western Reserve University
				13067	<BR>
				13068
Chet Ramey	0001803	2011-11-21 20:51:19 -0500	[diff] [blame]	13069	<A HREF="mailto:chet.ramey@case.edu">chet.ramey@case.edu</A>
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	13070	<A NAME="lbDG"> </A>
				13071	<H3>BUG REPORTS</H3>
				13072
				13073	If you find a bug in
				13074	<B>bash,</B>
				13075
				13076	you should report it. But first, you should
				13077	make sure that it really is a bug, and that it appears in the latest
				13078	version of
				13079	<B>bash</B>.
				13080
				13081	The latest version is always available from
Chet Ramey	495aee4	2011-11-22 19:11:26 -0500	[diff] [blame]	13082	<I><A HREF="ftp://ftp.gnu.org/pub/gnu/bash/">ftp://ftp.gnu.org/pub/gnu/bash/</A></I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	13083	<P>
				13084
				13085	Once you have determined that a bug actually exists, use the
				13086	<I>bashbug</I>
				13087
				13088	command to submit a bug report.
				13089	If you have a fix, you are encouraged to mail that as well!
				13090	Suggestions and `philosophical' bug reports may be mailed
				13091	to <I><A HREF="mailto:bug-bash@gnu.org">bug-bash@gnu.org</A></I> or posted to the Usenet
				13092	newsgroup
				13093	<A HREF="news:gnu.bash.bug">gnu.bash.bug</A>.
				13094
				13095	<P>
				13096
				13097	ALL bug reports should include:
				13098	<P>
				13099
				13100
				13101	<DL COMPACT>
				13102	<DT>The version number of <B>bash</B><DD>
				13103	<DT>The hardware and operating system<DD>
				13104	<DT>The compiler used to compile<DD>
				13105	<DT>A description of the bug behaviour<DD>
				13106	<DT>A short script or `recipe' which exercises the bug<DD>
				13107
				13108	</DL>
				13109	<P>
				13110
				13111	<I>bashbug</I>
				13112
				13113	inserts the first three items automatically into the template
				13114	it provides for filing a bug report.
				13115	<P>
				13116
				13117	Comments and bug reports concerning
				13118	this manual page should be directed to
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	13119	<I><A HREF="mailto:chet.ramey@case.edu">chet.ramey@case.edu</A></I>.
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	13120
				13121	<A NAME="lbDH"> </A>
				13122	<H3>BUGS</H3>
				13123
				13124	<P>
				13125
				13126	It's too big and too slow.
				13127	<P>
				13128
				13129	There are some subtle differences between
				13130	<B>bash</B>
				13131
				13132	and traditional versions of
				13133	<B>sh</B>,
				13134
				13135	mostly because of the
				13136	<FONT SIZE=-1><B>POSIX</B>
				13137
				13138	</FONT>
				13139	specification.
				13140	<P>
				13141
				13142	Aliases are confusing in some uses.
				13143	<P>
				13144
				13145	Shell builtin commands and functions are not stoppable/restartable.
				13146	<P>
				13147
				13148	Compound commands and command sequences of the form `a ; b ; c'
				13149	are not handled gracefully when process suspension is attempted.
				13150	When a process is stopped, the shell immediately executes the next
				13151	command in the sequence.
				13152	It suffices to place the sequence of commands between
				13153	parentheses to force it into a subshell, which may be stopped as
				13154	a unit.
				13155	<P>
				13156
				13157	Array variables may not (yet) be exported.
				13158	<P>
				13159
				13160	There may be only one active coprocess at a time.
				13161
				13162
				13163
				13164	<HR>
				13165	<TABLE WIDTH=100%>
				13166	<TR>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	13167	<TH ALIGN=LEFT width=33%>GNU Bash 4.3<TH ALIGN=CENTER width=33%>2014 February 2<TH ALIGN=RIGHT width=33%>BASH(1)
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	13168	</TR>
				13169	</TABLE>
				13170	<HR>
				13171	<A NAME="index"> </A><H2>Index</H2>
				13172	<DL>
				13173	<DT><A HREF="#lbAB">NAME</A><DD>
				13174	<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
				13175	<DT><A HREF="#lbAD">COPYRIGHT</A><DD>
				13176	<DT><A HREF="#lbAE">DESCRIPTION</A><DD>
				13177	<DT><A HREF="#lbAF">OPTIONS</A><DD>
				13178	<DT><A HREF="#lbAG">ARGUMENTS</A><DD>
				13179	<DT><A HREF="#lbAH">INVOCATION</A><DD>
				13180	<DT><A HREF="#lbAI">DEFINITIONS</A><DD>
				13181	<DT><A HREF="#lbAJ">RESERVED WORDS</A><DD>
				13182	<DT><A HREF="#lbAK">SHELL GRAMMAR</A><DD>
				13183	<DL>
				13184	<DT><A HREF="#lbAL">Simple Commands</A><DD>
				13185	<DT><A HREF="#lbAM">Pipelines</A><DD>
				13186	<DT><A HREF="#lbAN">Lists</A><DD>
				13187	<DT><A HREF="#lbAO">Compound Commands</A><DD>
				13188	<DT><A HREF="#lbAP">Coprocesses</A><DD>
				13189	<DT><A HREF="#lbAQ">Shell Function Definitions</A><DD>
				13190	</DL>
				13191	<DT><A HREF="#lbAR">COMMENTS</A><DD>
				13192	<DT><A HREF="#lbAS">QUOTING</A><DD>
				13193	<DT><A HREF="#lbAT">PARAMETERS</A><DD>
				13194	<DL>
				13195	<DT><A HREF="#lbAU">Positional Parameters</A><DD>
				13196	<DT><A HREF="#lbAV">Special Parameters</A><DD>
				13197	<DT><A HREF="#lbAW">Shell Variables</A><DD>
				13198	<DT><A HREF="#lbAX">Arrays</A><DD>
				13199	</DL>
				13200	<DT><A HREF="#lbAY">EXPANSION</A><DD>
				13201	<DL>
				13202	<DT><A HREF="#lbAZ">Brace Expansion</A><DD>
				13203	<DT><A HREF="#lbBA">Tilde Expansion</A><DD>
				13204	<DT><A HREF="#lbBB">Parameter Expansion</A><DD>
				13205	<DT><A HREF="#lbBC">Command Substitution</A><DD>
				13206	<DT><A HREF="#lbBD">Arithmetic Expansion</A><DD>
				13207	<DT><A HREF="#lbBE">Process Substitution</A><DD>
				13208	<DT><A HREF="#lbBF">Word Splitting</A><DD>
				13209	<DT><A HREF="#lbBG">Pathname Expansion</A><DD>
				13210	<DT><A HREF="#lbBH">Quote Removal</A><DD>
				13211	</DL>
				13212	<DT><A HREF="#lbBI">REDIRECTION</A><DD>
				13213	<DL>
				13214	<DT><A HREF="#lbBJ">Redirecting Input</A><DD>
				13215	<DT><A HREF="#lbBK">Redirecting Output</A><DD>
				13216	<DT><A HREF="#lbBL">Appending Redirected Output</A><DD>
				13217	<DT><A HREF="#lbBM">Redirecting Standard Output and Standard Error</A><DD>
				13218	<DT><A HREF="#lbBN">Appending Standard Output and Standard Error</A><DD>
				13219	<DT><A HREF="#lbBO">Here Documents</A><DD>
				13220	<DT><A HREF="#lbBP">Here Strings</A><DD>
				13221	<DT><A HREF="#lbBQ">Duplicating File Descriptors</A><DD>
				13222	<DT><A HREF="#lbBR">Moving File Descriptors</A><DD>
				13223	<DT><A HREF="#lbBS">Opening File Descriptors for Reading and Writing</A><DD>
				13224	</DL>
				13225	<DT><A HREF="#lbBT">ALIASES</A><DD>
				13226	<DT><A HREF="#lbBU">FUNCTIONS</A><DD>
				13227	<DT><A HREF="#lbBV">ARITHMETIC EVALUATION</A><DD>
				13228	<DT><A HREF="#lbBW">CONDITIONAL EXPRESSIONS</A><DD>
				13229	<DT><A HREF="#lbBX">SIMPLE COMMAND EXPANSION</A><DD>
				13230	<DT><A HREF="#lbBY">COMMAND EXECUTION</A><DD>
				13231	<DT><A HREF="#lbBZ">COMMAND EXECUTION ENVIRONMENT</A><DD>
				13232	<DT><A HREF="#lbCA">ENVIRONMENT</A><DD>
				13233	<DT><A HREF="#lbCB">EXIT STATUS</A><DD>
				13234	<DT><A HREF="#lbCC">SIGNALS</A><DD>
				13235	<DT><A HREF="#lbCD">JOB CONTROL</A><DD>
				13236	<DT><A HREF="#lbCE">PROMPTING</A><DD>
				13237	<DT><A HREF="#lbCF">READLINE</A><DD>
				13238	<DL>
				13239	<DT><A HREF="#lbCG">Readline Notation</A><DD>
				13240	<DT><A HREF="#lbCH">Readline Initialization</A><DD>
				13241	<DT><A HREF="#lbCI">Readline Key Bindings</A><DD>
				13242	<DT><A HREF="#lbCJ">Readline Variables</A><DD>
				13243	<DT><A HREF="#lbCK">Readline Conditional Constructs</A><DD>
				13244	<DT><A HREF="#lbCL">Searching</A><DD>
				13245	<DT><A HREF="#lbCM">Readline Command Names</A><DD>
				13246	<DT><A HREF="#lbCN">Commands for Moving</A><DD>
				13247	<DT><A HREF="#lbCO">Commands for Manipulating the History</A><DD>
				13248	<DT><A HREF="#lbCP">Commands for Changing Text</A><DD>
				13249	<DT><A HREF="#lbCQ">Killing and Yanking</A><DD>
				13250	<DT><A HREF="#lbCR">Numeric Arguments</A><DD>
				13251	<DT><A HREF="#lbCS">Completing</A><DD>
				13252	<DT><A HREF="#lbCT">Keyboard Macros</A><DD>
				13253	<DT><A HREF="#lbCU">Miscellaneous</A><DD>
				13254	<DT><A HREF="#lbCV">Programmable Completion</A><DD>
				13255	</DL>
				13256	<DT><A HREF="#lbCW">HISTORY</A><DD>
				13257	<DT><A HREF="#lbCX">HISTORY EXPANSION</A><DD>
				13258	<DL>
				13259	<DT><A HREF="#lbCY">Event Designators</A><DD>
				13260	<DT><A HREF="#lbCZ">Word Designators</A><DD>
				13261	<DT><A HREF="#lbDA">Modifiers</A><DD>
				13262	</DL>
				13263	<DT><A HREF="#lbDB">SHELL BUILTIN COMMANDS</A><DD>
				13264	<DT><A HREF="#lbDC">RESTRICTED SHELL</A><DD>
				13265	<DT><A HREF="#lbDD">SEE ALSO</A><DD>
				13266	<DT><A HREF="#lbDE">FILES</A><DD>
				13267	<DT><A HREF="#lbDF">AUTHORS</A><DD>
				13268	<DT><A HREF="#lbDG">BUG REPORTS</A><DD>
				13269	<DT><A HREF="#lbDH">BUGS</A><DD>
				13270	</DL>
				13271	<HR>
				13272	This document was created by man2html from bash.1.<BR>
Chet Ramey	ac50fba	2014-02-26 09:36:43 -0500	[diff] [blame]	13273	Time: 24 February 2014 08:28:34 EST
Jari Aalto	17345e5	2009-02-19 22:21:29 +0000	[diff] [blame]	13274	</BODY>
				13275	</HTML>