mirror of
https://https.git.savannah.gnu.org/git/bash.git
synced 2026-06-29 16:39:53 +02:00
commit bash-20200615 snapshot
This commit is contained in:
Chet Ramey
+370
-134
@@ -1,11 +1,11 @@
|
||||
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html>
|
||||
<!-- This text is a brief description of the features that are present in
|
||||
the Bash shell (version 5.0, 29 January 2020).
|
||||
the Bash shell (version 5.1, 5 June 2020).
|
||||
|
||||
This is Edition 5.0, last updated 29 January 2020,
|
||||
This is Edition 5.1, last updated 5 June 2020,
|
||||
of The GNU Bash Reference Manual,
|
||||
for Bash, Version 5.0.
|
||||
for Bash, Version 5.1.
|
||||
|
||||
Copyright (C) 1988-2018 Free Software Foundation, Inc.
|
||||
|
||||
@@ -92,17 +92,18 @@ ul.no-bullet {list-style: none}
|
||||
</ul></li>
|
||||
<li><a id="toc-Shell-Commands-1" href="#Shell-Commands">3.2 Shell Commands</a>
|
||||
<ul class="no-bullet">
|
||||
<li><a id="toc-Simple-Commands-1" href="#Simple-Commands">3.2.1 Simple Commands</a></li>
|
||||
<li><a id="toc-Pipelines-1" href="#Pipelines">3.2.2 Pipelines</a></li>
|
||||
<li><a id="toc-Lists-of-Commands" href="#Lists">3.2.3 Lists of Commands</a></li>
|
||||
<li><a id="toc-Compound-Commands-1" href="#Compound-Commands">3.2.4 Compound Commands</a>
|
||||
<li><a id="toc-Reserved-Words-1" href="#Reserved-Words">3.2.1 Reserved Words</a></li>
|
||||
<li><a id="toc-Simple-Commands-1" href="#Simple-Commands">3.2.2 Simple Commands</a></li>
|
||||
<li><a id="toc-Pipelines-1" href="#Pipelines">3.2.3 Pipelines</a></li>
|
||||
<li><a id="toc-Lists-of-Commands" href="#Lists">3.2.4 Lists of Commands</a></li>
|
||||
<li><a id="toc-Compound-Commands-1" href="#Compound-Commands">3.2.5 Compound Commands</a>
|
||||
<ul class="no-bullet">
|
||||
<li><a id="toc-Looping-Constructs-1" href="#Looping-Constructs">3.2.4.1 Looping Constructs</a></li>
|
||||
<li><a id="toc-Conditional-Constructs-1" href="#Conditional-Constructs">3.2.4.2 Conditional Constructs</a></li>
|
||||
<li><a id="toc-Grouping-Commands" href="#Command-Grouping">3.2.4.3 Grouping Commands</a></li>
|
||||
<li><a id="toc-Looping-Constructs-1" href="#Looping-Constructs">3.2.5.1 Looping Constructs</a></li>
|
||||
<li><a id="toc-Conditional-Constructs-1" href="#Conditional-Constructs">3.2.5.2 Conditional Constructs</a></li>
|
||||
<li><a id="toc-Grouping-Commands" href="#Command-Grouping">3.2.5.3 Grouping Commands</a></li>
|
||||
</ul></li>
|
||||
<li><a id="toc-Coprocesses-1" href="#Coprocesses">3.2.5 Coprocesses</a></li>
|
||||
<li><a id="toc-GNU-Parallel-1" href="#GNU-Parallel">3.2.6 GNU Parallel</a></li>
|
||||
<li><a id="toc-Coprocesses-1" href="#Coprocesses">3.2.6 Coprocesses</a></li>
|
||||
<li><a id="toc-GNU-Parallel-1" href="#GNU-Parallel">3.2.7 GNU Parallel</a></li>
|
||||
</ul></li>
|
||||
<li><a id="toc-Shell-Functions-1" href="#Shell-Functions">3.3 Shell Functions</a></li>
|
||||
<li><a id="toc-Shell-Parameters-1" href="#Shell-Parameters">3.4 Shell Parameters</a>
|
||||
@@ -186,6 +187,7 @@ ul.no-bullet {list-style: none}
|
||||
<li><a id="toc-Controlling-the-Prompt-1" href="#Controlling-the-Prompt">6.9 Controlling the Prompt</a></li>
|
||||
<li><a id="toc-The-Restricted-Shell-1" href="#The-Restricted-Shell">6.10 The Restricted Shell</a></li>
|
||||
<li><a id="toc-Bash-POSIX-Mode-1" href="#Bash-POSIX-Mode">6.11 Bash POSIX Mode</a></li>
|
||||
<li><a id="toc-Shell-Compatibility-Mode-1" href="#Shell-Compatibility-Mode">6.12 Shell Compatibility Mode</a></li>
|
||||
</ul></li>
|
||||
<li><a id="toc-Job-Control-1" href="#Job-Control">7 Job Control</a>
|
||||
<ul class="no-bullet">
|
||||
@@ -273,12 +275,12 @@ Next: <a href="#Introduction" accesskey="n" rel="next">Introduction</a>, Previou
|
||||
<span id="Bash-Features-1"></span><h1 class="top">Bash Features</h1>
|
||||
|
||||
<p>This text is a brief description of the features that are present in
|
||||
the Bash shell (version 5.0, 29 January 2020).
|
||||
the Bash shell (version 5.1, 5 June 2020).
|
||||
The Bash home page is <a href="http://www.gnu.org/software/bash/">http://www.gnu.org/software/bash/</a>.
|
||||
</p>
|
||||
<p>This is Edition 5.0, last updated 29 January 2020,
|
||||
<p>This is Edition 5.1, last updated 5 June 2020,
|
||||
of <cite>The GNU Bash Reference Manual</cite>,
|
||||
for <code>Bash</code>, Version 5.0.
|
||||
for <code>Bash</code>, Version 5.1.
|
||||
</p>
|
||||
<p>Bash contains features that appear in other popular shells, and some
|
||||
features that only appear in Bash. Some of the shells that Bash has
|
||||
@@ -859,10 +861,15 @@ Previous: <a href="#ANSI_002dC-Quoting" accesskey="p" rel="prev">ANSI-C Quoting<
|
||||
<span id="index-native-languages"></span>
|
||||
<span id="index-translation_002c-native-languages"></span>
|
||||
|
||||
<p>A double-quoted string preceded by a dollar sign (‘<samp>$</samp>’) will cause
|
||||
the string to be translated according to the current locale.
|
||||
If the current locale is <code>C</code> or <code>POSIX</code>, the dollar sign
|
||||
is ignored.
|
||||
<p>A double-quoted string preceded by a dollar sign (‘<samp>$</samp>’)
|
||||
will cause the string to be translated according to the current locale.
|
||||
The <var>gettext</var> infrastructure performs the message catalog lookup and
|
||||
translation, using the <code>LC_MESSAGES</code> and <code>TEXTDOMAIN</code> shell
|
||||
variables, as explained below. See the gettext documentation for additional
|
||||
details.
|
||||
If the current locale is <code>C</code> or <code>POSIX</code>,
|
||||
or if there are no translations available,
|
||||
the dollar sign is ignored.
|
||||
If the string is translated and replaced, the replacement is
|
||||
double-quoted.
|
||||
</p>
|
||||
@@ -914,27 +921,55 @@ becomes the input of a second, in a loop or conditional construct, or in
|
||||
some other grouping.
|
||||
</p>
|
||||
<table class="menu" border="0" cellspacing="0">
|
||||
<tr><td align="left" valign="top">• <a href="#Simple-Commands" accesskey="1">Simple Commands</a></td><td> </td><td align="left" valign="top">The most common type of command.
|
||||
<tr><td align="left" valign="top">• <a href="#Reserved-Words" accesskey="1">Reserved Words</a></td><td> </td><td align="left" valign="top">Words that have special meaning to the shell.
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top">• <a href="#Pipelines" accesskey="2">Pipelines</a></td><td> </td><td align="left" valign="top">Connecting the input and output of several
|
||||
<tr><td align="left" valign="top">• <a href="#Simple-Commands" accesskey="2">Simple Commands</a></td><td> </td><td align="left" valign="top">The most common type of command.
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top">• <a href="#Pipelines" accesskey="3">Pipelines</a></td><td> </td><td align="left" valign="top">Connecting the input and output of several
|
||||
commands.
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top">• <a href="#Lists" accesskey="3">Lists</a></td><td> </td><td align="left" valign="top">How to execute commands sequentially.
|
||||
<tr><td align="left" valign="top">• <a href="#Lists" accesskey="4">Lists</a></td><td> </td><td align="left" valign="top">How to execute commands sequentially.
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top">• <a href="#Compound-Commands" accesskey="4">Compound Commands</a></td><td> </td><td align="left" valign="top">Shell commands for control flow.
|
||||
<tr><td align="left" valign="top">• <a href="#Compound-Commands" accesskey="5">Compound Commands</a></td><td> </td><td align="left" valign="top">Shell commands for control flow.
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top">• <a href="#Coprocesses" accesskey="5">Coprocesses</a></td><td> </td><td align="left" valign="top">Two-way communication between commands.
|
||||
<tr><td align="left" valign="top">• <a href="#Coprocesses" accesskey="6">Coprocesses</a></td><td> </td><td align="left" valign="top">Two-way communication between commands.
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top">• <a href="#GNU-Parallel" accesskey="6">GNU Parallel</a></td><td> </td><td align="left" valign="top">Running commands in parallel.
|
||||
<tr><td align="left" valign="top">• <a href="#GNU-Parallel" accesskey="7">GNU Parallel</a></td><td> </td><td align="left" valign="top">Running commands in parallel.
|
||||
</td></tr>
|
||||
</table>
|
||||
|
||||
<hr>
|
||||
<span id="Reserved-Words"></span><div class="header">
|
||||
<p>
|
||||
Next: <a href="#Simple-Commands" accesskey="n" rel="next">Simple Commands</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Reserved-Words-1"></span><h4 class="subsection">3.2.1 Reserved Words</h4>
|
||||
<span id="index-reserved-words"></span>
|
||||
|
||||
<p>Reserved words are words that have special meaning to the shell.
|
||||
They are used to begin and end the shell’s compound commands.
|
||||
</p>
|
||||
<p>The following words are recognized as reserved when unquoted and
|
||||
the first word of a command (see below for exceptions):
|
||||
</p>
|
||||
<table>
|
||||
<tr><td width="10%"><code>if</code></td><td width="10%"><code>then</code></td><td width="10%"><code>elif</code></td><td width="10%"><code>else</code></td><td width="12%"><code>fi</code></td><td width="10%"><code>time</code></td></tr>
|
||||
<tr><td width="10%"><code>for</code></td><td width="10%"><code>in</code></td><td width="10%"><code>until</code></td><td width="10%"><code>while</code></td><td width="12%"><code>do</code></td><td width="10%"><code>done</code></td></tr>
|
||||
<tr><td width="10%"><code>case</code></td><td width="10%"><code>esac</code></td><td width="10%"><code>coproc</code></td><td width="10%"><code>select</code></td><td width="12%"><code>function</code></td></tr>
|
||||
<tr><td width="10%"><code>{</code></td><td width="10%"><code>}</code></td><td width="10%"><code>[[</code></td><td width="10%"><code>]]</code></td><td width="12%"><code>!</code></td></tr>
|
||||
</table>
|
||||
|
||||
<p><code>in</code> is recognized as a reserved word if it is the third word of a
|
||||
<code>case</code> or <code>select</code> command.
|
||||
<code>in</code> and <code>do</code> are recognized as reserved
|
||||
words if they are the third word in a <code>for</code> command.
|
||||
</p>
|
||||
<hr>
|
||||
<span id="Simple-Commands"></span><div class="header">
|
||||
<p>
|
||||
Next: <a href="#Pipelines" accesskey="n" rel="next">Pipelines</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
Next: <a href="#Pipelines" accesskey="n" rel="next">Pipelines</a>, Previous: <a href="#Reserved-Words" accesskey="p" rel="prev">Reserved Words</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Simple-Commands-1"></span><h4 class="subsection">3.2.1 Simple Commands</h4>
|
||||
<span id="Simple-Commands-1"></span><h4 class="subsection">3.2.2 Simple Commands</h4>
|
||||
<span id="index-commands_002c-simple"></span>
|
||||
|
||||
<p>A simple command is the kind of command encountered most often.
|
||||
@@ -953,7 +988,7 @@ the command was terminated by signal <var>n</var>.
|
||||
<p>
|
||||
Next: <a href="#Lists" accesskey="n" rel="next">Lists</a>, Previous: <a href="#Simple-Commands" accesskey="p" rel="prev">Simple Commands</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Pipelines-1"></span><h4 class="subsection">3.2.2 Pipelines</h4>
|
||||
<span id="Pipelines-1"></span><h4 class="subsection">3.2.3 Pipelines</h4>
|
||||
<span id="index-pipeline"></span>
|
||||
<span id="index-commands_002c-pipelines"></span>
|
||||
|
||||
@@ -1030,7 +1065,7 @@ returning a value.
|
||||
<p>
|
||||
Next: <a href="#Compound-Commands" accesskey="n" rel="next">Compound Commands</a>, Previous: <a href="#Pipelines" accesskey="p" rel="prev">Pipelines</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Lists-of-Commands"></span><h4 class="subsection">3.2.3 Lists of Commands</h4>
|
||||
<span id="Lists-of-Commands"></span><h4 class="subsection">3.2.4 Lists of Commands</h4>
|
||||
<span id="index-commands_002c-lists"></span>
|
||||
|
||||
<p>A <code>list</code> is a sequence of one or more pipelines separated by one
|
||||
@@ -1089,7 +1124,7 @@ executed in the list.
|
||||
<p>
|
||||
Next: <a href="#Coprocesses" accesskey="n" rel="next">Coprocesses</a>, Previous: <a href="#Lists" accesskey="p" rel="prev">Lists</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Compound-Commands-1"></span><h4 class="subsection">3.2.4 Compound Commands</h4>
|
||||
<span id="Compound-Commands-1"></span><h4 class="subsection">3.2.5 Compound Commands</h4>
|
||||
<span id="index-commands_002c-compound"></span>
|
||||
|
||||
<table class="menu" border="0" cellspacing="0">
|
||||
@@ -1119,7 +1154,7 @@ to group commands and execute them as a unit.
|
||||
<p>
|
||||
Next: <a href="#Conditional-Constructs" accesskey="n" rel="next">Conditional Constructs</a>, Up: <a href="#Compound-Commands" accesskey="u" rel="up">Compound Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Looping-Constructs-1"></span><h4 class="subsubsection">3.2.4.1 Looping Constructs</h4>
|
||||
<span id="Looping-Constructs-1"></span><h4 class="subsubsection">3.2.5.1 Looping Constructs</h4>
|
||||
<span id="index-commands_002c-looping"></span>
|
||||
|
||||
<p>Bash supports the following looping constructs.
|
||||
@@ -1204,7 +1239,7 @@ may be used to control loop execution.
|
||||
<p>
|
||||
Next: <a href="#Command-Grouping" accesskey="n" rel="next">Command Grouping</a>, Previous: <a href="#Looping-Constructs" accesskey="p" rel="prev">Looping Constructs</a>, Up: <a href="#Compound-Commands" accesskey="u" rel="up">Compound Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Conditional-Constructs-1"></span><h4 class="subsubsection">3.2.4.2 Conditional Constructs</h4>
|
||||
<span id="Conditional-Constructs-1"></span><h4 class="subsubsection">3.2.5.2 Conditional Constructs</h4>
|
||||
<span id="index-commands_002c-conditional"></span>
|
||||
|
||||
<dl compact="compact">
|
||||
@@ -1517,7 +1552,7 @@ value of the entire conditional expression.
|
||||
<p>
|
||||
Previous: <a href="#Conditional-Constructs" accesskey="p" rel="prev">Conditional Constructs</a>, Up: <a href="#Compound-Commands" accesskey="u" rel="up">Compound Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Grouping-Commands"></span><h4 class="subsubsection">3.2.4.3 Grouping Commands</h4>
|
||||
<span id="Grouping-Commands"></span><h4 class="subsubsection">3.2.5.3 Grouping Commands</h4>
|
||||
<span id="index-commands_002c-grouping"></span>
|
||||
|
||||
<p>Bash provides two ways to group a list of commands to be executed
|
||||
@@ -1567,7 +1602,7 @@ from the <var>list</var> by whitespace.
|
||||
<p>
|
||||
Next: <a href="#GNU-Parallel" accesskey="n" rel="next">GNU Parallel</a>, Previous: <a href="#Compound-Commands" accesskey="p" rel="prev">Compound Commands</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Coprocesses-1"></span><h4 class="subsection">3.2.5 Coprocesses</h4>
|
||||
<span id="Coprocesses-1"></span><h4 class="subsection">3.2.6 Coprocesses</h4>
|
||||
<span id="index-coprocess"></span>
|
||||
|
||||
<p>A <code>coprocess</code> is a shell command preceded by the <code>coproc</code>
|
||||
@@ -1617,7 +1652,7 @@ The return status of a coprocess is the exit status of <var>command</var>.
|
||||
<p>
|
||||
Previous: <a href="#Coprocesses" accesskey="p" rel="prev">Coprocesses</a>, Up: <a href="#Shell-Commands" accesskey="u" rel="up">Shell Commands</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="GNU-Parallel-1"></span><h4 class="subsection">3.2.6 GNU Parallel</h4>
|
||||
<span id="GNU-Parallel-1"></span><h4 class="subsection">3.2.7 GNU Parallel</h4>
|
||||
|
||||
<p>There are ways to run commands in parallel that are not built into Bash.
|
||||
GNU Parallel is a tool to do just that.
|
||||
@@ -2630,7 +2665,7 @@ results.
|
||||
</p>
|
||||
<p>Substring indexing is zero-based unless the positional parameters
|
||||
are used, in which case the indexing starts at 1 by default.
|
||||
If <var>offset</var> is 0, and the positional parameters are used, <code>$@</code> is
|
||||
If <var>offset</var> is 0, and the positional parameters are used, <code>$0</code> is
|
||||
prefixed to the list.
|
||||
</p>
|
||||
</dd>
|
||||
@@ -2764,6 +2799,18 @@ or information about <var>parameter</var> itself, depending on the value of
|
||||
<var>operator</var>. Each <var>operator</var> is a single letter:
|
||||
</p>
|
||||
<dl compact="compact">
|
||||
<dt><code>U</code></dt>
|
||||
<dd><p>The expansion is a string that is the value of <var>parameter</var> with lowercase
|
||||
alphabetic characters converted to uppercase.
|
||||
</p></dd>
|
||||
<dt><code>u</code></dt>
|
||||
<dd><p>The expansion is a string that is the value of <var>parameter</var> with the first
|
||||
character converted to uppercase, if it is alphabetic.
|
||||
</p></dd>
|
||||
<dt><code>L</code></dt>
|
||||
<dd><p>The expansion is a string that is the value of <var>parameter</var> with uppercase
|
||||
alphabetic characters converted to lowercase.
|
||||
</p></dd>
|
||||
<dt><code>Q</code></dt>
|
||||
<dd><p>The expansion is a string that is the value of <var>parameter</var> quoted in a
|
||||
format that can be reused as input.
|
||||
@@ -2781,6 +2828,12 @@ escape sequences expanded as with the <code>$'…'</code> quoting mechanism
|
||||
an assignment statement or <code>declare</code> command that, if
|
||||
evaluated, will recreate <var>parameter</var> with its attributes and value.
|
||||
</p></dd>
|
||||
<dt><code>K</code></dt>
|
||||
<dd><p>Produces a possibly-quoted version of the value of <var>parameter</var>,
|
||||
except that it prints the values of
|
||||
indexed and associative arrays as a sequence of quoted key-value pairs
|
||||
(see <a href="#Arrays">Arrays</a>).
|
||||
</p></dd>
|
||||
<dt><code>a</code></dt>
|
||||
<dd><p>The expansion is a string consisting of flag values representing
|
||||
<var>parameter</var>’s attributes.
|
||||
@@ -4703,7 +4756,7 @@ zero if <var>command</var> is found, and non-zero if not.
|
||||
<dt><code>declare</code></dt>
|
||||
<dd><span id="index-declare"></span>
|
||||
<div class="example">
|
||||
<pre class="example">declare [-aAfFgilnrtux] [-p] [<var>name</var>[=<var>value</var>] …]
|
||||
<pre class="example">declare [-aAfFgiIlnrtux] [-p] [<var>name</var>[=<var>value</var>] …]
|
||||
</pre></div>
|
||||
|
||||
<p>Declare variables and give them attributes. If no <var>name</var>s
|
||||
@@ -4732,6 +4785,12 @@ each <var>name</var> is defined are displayed as well.
|
||||
the global scope, even when <code>declare</code> is executed in a shell function.
|
||||
It is ignored in all other cases.
|
||||
</p>
|
||||
<p>The <samp>-I</samp> option causes local variables to inherit the attributes
|
||||
(except the <var>nameref</var> attribute)
|
||||
and value of any existing variable with the same
|
||||
<var>name</var> at a surrounding scope.
|
||||
If there is no existing variable, the local variable is initially unset.
|
||||
</p>
|
||||
<p>The following options can be used to restrict output to variables with
|
||||
the specified attributes or to give variables attributes:
|
||||
</p>
|
||||
@@ -5098,6 +5157,11 @@ This is an exception to the usual <code>printf</code> behavior.
|
||||
</p></dd>
|
||||
</dl>
|
||||
|
||||
<p>The %b, %q, and %T directives all use the field width and precision
|
||||
arguments from the format specification and write that many bytes from
|
||||
(or use that wide a field for) the expanded argument, which usually
|
||||
contains more characters than the original.
|
||||
</p>
|
||||
<p>Arguments to non-string format specifiers are treated as C language constants,
|
||||
except that a leading plus or minus sign is allowed, and if the leading
|
||||
character is a single or double quote, the value is the ASCII value of
|
||||
@@ -5369,7 +5433,7 @@ allow this value to be set).
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>-q</code></dt>
|
||||
<dd><p>The maximum number of bytes in POSIX message queues.
|
||||
<dd><p>The maximum number of bytes in <small>POSIX</small> message queues.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>-r</code></dt>
|
||||
@@ -5401,6 +5465,10 @@ some systems, to its children.
|
||||
<dd><p>The maximum number of pseudoterminals.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>-R</code></dt>
|
||||
<dd><p>The maximum time a real-time process can run before blocking, in microseconds.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>-T</code></dt>
|
||||
<dd><p>The maximum number of threads.
|
||||
</p></dd>
|
||||
@@ -5418,8 +5486,10 @@ is printed, unless the <samp>-H</samp> option is supplied.
|
||||
When setting new limits, if neither <samp>-H</samp> nor <samp>-S</samp> is supplied,
|
||||
both the hard and soft limits are set.
|
||||
If no option is given, then <samp>-f</samp> is assumed. Values are in 1024-byte
|
||||
increments, except for <samp>-t</samp>, which is in seconds; <samp>-p</samp>,
|
||||
which is in units of 512-byte blocks;
|
||||
increments, except for
|
||||
<samp>-t</samp>, which is in seconds;
|
||||
<samp>-R</samp>, which is in microseconds;
|
||||
<samp>-p</samp>, which is in units of 512-byte blocks;
|
||||
<samp>-P</samp>,
|
||||
<samp>-T</samp>,
|
||||
<samp>-b</samp>,
|
||||
@@ -5927,67 +5997,14 @@ history is enabled (see <a href="#Bash-History-Facilities">Bash History Faciliti
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>compat31</code></dt>
|
||||
<dd><p>If set, Bash
|
||||
changes its behavior to that of version 3.1 with respect to quoted
|
||||
arguments to the conditional command’s ‘<samp>=~</samp>’ operator
|
||||
and with respect to locale-specific
|
||||
string comparison when using the <code>[[</code>
|
||||
conditional command’s ‘<samp><</samp>’ and ‘<samp>></samp>’ operators.
|
||||
Bash versions prior to bash-4.1 use ASCII collation and strcmp(3);
|
||||
bash-4.1 and later use the current locale’s collation sequence and strcoll(3).
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>compat32</code></dt>
|
||||
<dd><p>If set, Bash
|
||||
changes its behavior to that of version 3.2 with respect to locale-specific
|
||||
string comparison when using the <code>[[</code>
|
||||
conditional command’s ‘<samp><</samp>’ and ‘<samp>></samp>’ operators (see previous item)
|
||||
and the effect of interrupting a command list.
|
||||
Bash versions 3.2 and earlier continue with the next command in the list
|
||||
after one terminates due to an interrupt.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>compat40</code></dt>
|
||||
<dd><p>If set, Bash
|
||||
changes its behavior to that of version 4.0 with respect to locale-specific
|
||||
string comparison when using the <code>[[</code>
|
||||
conditional command’s ‘<samp><</samp>’ and ‘<samp>></samp>’ operators (see description
|
||||
of <code>compat31</code>)
|
||||
and the effect of interrupting a command list.
|
||||
Bash versions 4.0 and later interrupt the list as if the shell received the
|
||||
interrupt; previous versions continue with the next command in the list.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>compat41</code></dt>
|
||||
<dd><p>If set, Bash, when in <small>POSIX</small> mode, treats a single quote in a double-quoted
|
||||
parameter expansion as a special character. The single quotes must match
|
||||
(an even number) and the characters between the single quotes are considered
|
||||
quoted. This is the behavior of <small>POSIX</small> mode through version 4.1.
|
||||
The default Bash behavior remains as in previous versions.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>compat42</code></dt>
|
||||
<dd><p>If set, Bash
|
||||
does not process the replacement string in the pattern substitution word
|
||||
expansion using quote removal.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>compat43</code></dt>
|
||||
<dd><p>If set, Bash
|
||||
does not print a warning message if an attempt is made to use a quoted compound
|
||||
array assignment as an argument to <code>declare</code>,
|
||||
makes word expansion errors
|
||||
non-fatal errors that cause the current command to fail (the default behavior is
|
||||
to make them fatal errors that cause the shell to exit),
|
||||
and does not reset the
|
||||
loop state when a shell function is executed (this allows <code>break</code> or
|
||||
<code>continue</code> in a shell function to affect loops in the caller’s context).
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>compat44</code></dt>
|
||||
<dd><p>If set, Bash
|
||||
saves the positional parameters to BASH_ARGV and BASH_ARGC before they are
|
||||
used, regardless of whether or not extended debugging mode is enabled.
|
||||
<dd><p>These control aspects of the shell’s compatibility mode
|
||||
(see <a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>).
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>complete_fullquote</code></dt>
|
||||
@@ -6446,7 +6463,7 @@ variables for controlling the job control facilities
|
||||
</dt>
|
||||
<dd><span id="index-_0024_005f"></span>
|
||||
<p>($_, an underscore.)
|
||||
At shell startup, set to the absolute pathname used to invoke the
|
||||
At shell startup, set to the pathname used to invoke the
|
||||
shell or shell script being executed as passed in the environment
|
||||
or argument list.
|
||||
Subsequently, expands to the last argument to the previous simple
|
||||
@@ -6578,8 +6595,8 @@ subsequently reset.
|
||||
<span id="index-BASH_005fCOMPAT"></span>
|
||||
</dt>
|
||||
<dd><p>The value is used to set the shell’s compatibility level.
|
||||
See <a href="#The-Shopt-Builtin">The Shopt Builtin</a>, for a description of the various compatibility
|
||||
levels and their effects.
|
||||
See <a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>, for a description of the various
|
||||
compatibility levels and their effects.
|
||||
The value may be a decimal number (e.g., 4.2) or an integer (e.g., 42)
|
||||
corresponding to the desired compatibility level.
|
||||
If <code>BASH_COMPAT</code> is unset or set to the empty string, the compatibility
|
||||
@@ -6587,9 +6604,11 @@ level is set to the default for the current version.
|
||||
If <code>BASH_COMPAT</code> is set to a value that is not one of the valid
|
||||
compatibility levels, the shell prints an error message and sets the
|
||||
compatibility level to the default for the current version.
|
||||
The valid compatibility levels correspond to the compatibility options
|
||||
accepted by the <code>shopt</code> builtin described above (for example,
|
||||
<var>compat42</var> means that 4.2 and 42 are valid values).
|
||||
The valid values correspond to the compatibility levels
|
||||
described below (see <a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a>).
|
||||
For example, 4.2 and 42 are valid values that correspond
|
||||
to the <code>compat42</code> <code>shopt</code> option
|
||||
and set the compatibility level to 42.
|
||||
The current version is also a valid value.
|
||||
</p>
|
||||
</dd>
|
||||
@@ -7002,6 +7021,7 @@ parser to treat the rest of the line as a comment.
|
||||
</dt>
|
||||
<dd><p>The history number, or index in the history list, of the current
|
||||
command.
|
||||
Assignments to <code>HISTCMD</code> are ignored.
|
||||
If <code>HISTCMD</code>
|
||||
is unset, it loses its special properties,
|
||||
even if it is subsequently reset.
|
||||
@@ -7302,11 +7322,15 @@ not already set.
|
||||
is readonly.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>PROMPT_COMMAND</code>
|
||||
<span id="index-PROMPT_005fCOMMAND"></span>
|
||||
<dt><code>PROMPT_COMMANDS</code>
|
||||
<span id="index-PROMPT_005fCOMMANDS"></span>
|
||||
</dt>
|
||||
<dd><p>If set, the value is interpreted as a command to execute
|
||||
before the printing of each primary prompt (<code>$PS1</code>).
|
||||
<dd><p>If this array variable is set,
|
||||
the value of each set element is interpreted as a command to execute
|
||||
before printing the primary prompt (<code>$PS1</code>).
|
||||
If this is not set, but
|
||||
<code>PROMPT_COMMAND</code>
|
||||
is set to a value, its value is used as a command to execute instead.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>PROMPT_DIRTRIM</code>
|
||||
@@ -7321,7 +7345,7 @@ Characters removed are replaced with an ellipsis.
|
||||
<dt><code>PS0</code>
|
||||
<span id="index-PS0"></span>
|
||||
</dt>
|
||||
<dd><p>The value of this parameter is expanded like <var>PS1</var>
|
||||
<dd><p>The value of this parameter is expanded like <code>PS1</code>
|
||||
and displayed by interactive shells after reading a command
|
||||
and before the command is executed.
|
||||
</p>
|
||||
@@ -7400,6 +7424,8 @@ shell was started. Assignment to this variable resets
|
||||
the count to the value assigned, and the expanded value
|
||||
becomes the value assigned plus the number of seconds
|
||||
since the assignment.
|
||||
The number of seconds at shell invocation and the current time is always
|
||||
determined by querying the system clock.
|
||||
If <code>SECONDS</code>
|
||||
is unset, it loses its special properties,
|
||||
even if it is subsequently reset.
|
||||
@@ -7567,6 +7593,9 @@ Next: <a href="#Job-Control" accesskey="n" rel="next">Job Control</a>, Previous:
|
||||
<tr><td align="left" valign="top">• <a href="#Bash-POSIX-Mode">Bash POSIX Mode</a></td><td> </td><td align="left" valign="top">Making Bash behave more closely to what
|
||||
the POSIX standard specifies.
|
||||
</td></tr>
|
||||
<tr><td align="left" valign="top">• <a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></td><td> </td><td align="left" valign="top">How Bash supports behavior that was present
|
||||
in earlier versions and has changed.
|
||||
</td></tr>
|
||||
</table>
|
||||
|
||||
<hr>
|
||||
@@ -7971,8 +8000,8 @@ executing it.
|
||||
See <a href="#Controlling-the-Prompt">Controlling the Prompt</a>, for a complete list of prompt
|
||||
string escape sequences.
|
||||
|
||||
</li><li> Bash executes the value of the <code>PROMPT_COMMAND</code> variable as a command
|
||||
before printing the primary prompt, <code>$PS1</code>
|
||||
</li><li> Bash executes the values of the set elements of the <code>PROMPT_COMMANDS</code>
|
||||
array variable as commands before printing the primary prompt, <code>$PS1</code>
|
||||
(see <a href="#Bash-Variables">Bash Variables</a>).
|
||||
|
||||
</li><li> Readline (see <a href="#Command-Line-Editing">Command Line Editing</a>) is used to read commands from
|
||||
@@ -8477,14 +8506,27 @@ an array.
|
||||
<pre class="example"><var>name</var>=(<var>value1</var> <var>value2</var> … )
|
||||
</pre></div>
|
||||
<p>where each
|
||||
<var>value</var> is of the form <code>[<var>subscript</var>]=</code><var>string</var>.
|
||||
<var>value</var> may be of the form <code>[<var>subscript</var>]=</code><var>string</var>.
|
||||
Indexed array assignments do not require anything but <var>string</var>.
|
||||
When assigning to indexed arrays, if
|
||||
the optional subscript is supplied, that index is assigned to;
|
||||
otherwise the index of the element assigned is the last index assigned
|
||||
to by the statement plus one. Indexing starts at zero.
|
||||
</p>
|
||||
<p>When assigning to an associative array, the subscript is required.
|
||||
<p>Each <var>value</var> in the list undergoes all the shell expansions
|
||||
described above (see <a href="#Shell-Expansions">Shell Expansions</a>).
|
||||
</p>
|
||||
<p>When assigning to an associative array, the words in a compound assignment
|
||||
may be either assignment statements, for which the subscript is required,
|
||||
or a list of words that is interpreted as a sequence of alternating keys
|
||||
and values:
|
||||
<var>name</var>=(<var>key1</var> <var>value1</var> <var>key2</var> <var>value2</var> … ).
|
||||
These are treated identically to
|
||||
<var>name</var>=( [<var>key1</var>]=<var>value1</var> [<var>key2</var>]=<var>value2</var> … ).
|
||||
The first word in the list determines how the remaining words
|
||||
are interpreted; all assignments in a list must be of the same type.
|
||||
When using key/value pairs, the keys may not be missing or empty;
|
||||
a final missing value is treated like the empty string.
|
||||
</p>
|
||||
<p>This syntax is also accepted by the <code>declare</code>
|
||||
builtin. Individual array elements may be assigned to using the
|
||||
@@ -8709,10 +8751,11 @@ Next: <a href="#The-Restricted-Shell" accesskey="n" rel="next">The Restricted Sh
|
||||
<span id="Controlling-the-Prompt-1"></span><h3 class="section">6.9 Controlling the Prompt</h3>
|
||||
<span id="index-prompting"></span>
|
||||
|
||||
<p>The value of the variable <code>PROMPT_COMMAND</code> is examined just before
|
||||
Bash prints each primary prompt. If <code>PROMPT_COMMAND</code> is set and
|
||||
has a non-null value, then the
|
||||
value is executed just as if it had been typed on the command line.
|
||||
<p>Bash examines the value of the array variable <code>PROMPT_COMMANDS</code> just before
|
||||
printing each primary prompt.
|
||||
If any elements in <code>PROMPT_COMMANDS</code> are set and non-null, Bash
|
||||
executes each value, in numeric order,
|
||||
just as if it had been typed on the command line.
|
||||
</p>
|
||||
<p>In addition, the following table describes the special characters which
|
||||
can appear in the prompt variables <code>PS0</code>, <code>PS1</code>, <code>PS2</code>, and
|
||||
@@ -8843,10 +8886,13 @@ with the exception that the following are disallowed or not performed:
|
||||
<ul>
|
||||
<li> Changing directories with the <code>cd</code> builtin.
|
||||
</li><li> Setting or unsetting the values of the <code>SHELL</code>, <code>PATH</code>,
|
||||
<code>HISTFILE</code>,
|
||||
<code>ENV</code>, or <code>BASH_ENV</code> variables.
|
||||
</li><li> Specifying command names containing slashes.
|
||||
</li><li> Specifying a filename containing a slash as an argument to the <code>.</code>
|
||||
builtin command.
|
||||
</li><li> Specifying a filename containing a slash as an argument to the <code>history</code>
|
||||
builtin command.
|
||||
</li><li> Specifying a filename containing a slash as an argument to the <samp>-p</samp>
|
||||
option to the <code>hash</code> builtin command.
|
||||
</li><li> Importing function definitions from the shell environment at startup.
|
||||
@@ -8883,7 +8929,7 @@ such as <code>jails</code>, <code>zones</code>, or <code>containers</code>.
|
||||
<hr>
|
||||
<span id="Bash-POSIX-Mode"></span><div class="header">
|
||||
<p>
|
||||
Previous: <a href="#The-Restricted-Shell" accesskey="p" rel="prev">The Restricted Shell</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
Next: <a href="#Shell-Compatibility-Mode" accesskey="n" rel="next">Shell Compatibility Mode</a>, Previous: <a href="#The-Restricted-Shell" accesskey="p" rel="prev">The Restricted Shell</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Bash-POSIX-Mode-1"></span><h3 class="section">6.11 Bash POSIX Mode</h3>
|
||||
<span id="index-POSIX-Mode"></span>
|
||||
@@ -8973,6 +9019,7 @@ not have to appear as matched pairs.
|
||||
</li><li> The parser does not recognize <code>time</code> as a reserved word if the next
|
||||
token begins with a ‘<samp>-</samp>’.
|
||||
|
||||
|
||||
</li><li> The ‘<samp>!</samp>’ character does not introduce history expansion within a
|
||||
double-quoted string, even if the <code>histexpand</code> option is enabled.
|
||||
|
||||
@@ -9018,10 +9065,6 @@ double-quoted.
|
||||
</li><li> Assignment statements preceding <small>POSIX</small> special builtins
|
||||
persist in the shell environment after the builtin completes.
|
||||
|
||||
</li><li> Assignment statements preceding shell function calls persist in the
|
||||
shell environment after the function returns, as if a <small>POSIX</small>
|
||||
special builtin command had been executed.
|
||||
|
||||
</li><li> The <code>command</code> builtin does not prevent builtins that take assignment
|
||||
statements as arguments from expanding them as assignment statements;
|
||||
when not in <small>POSIX</small> mode, assignment builtins lose their assignment
|
||||
@@ -9050,6 +9093,9 @@ is a valid signal number. If users want to reset the handler for a given
|
||||
signal to the original disposition, they should use ‘<samp>-</samp>’ as the
|
||||
first argument.
|
||||
|
||||
</li><li> <code>trap -p</code> displays signals whose dispositions are set to SIG_DFL and
|
||||
those that were ignored when the shell started.
|
||||
|
||||
</li><li> The <code>.</code> and <code>source</code> builtins do not search the current directory
|
||||
for the filename argument if it is not found by searching <code>PATH</code>.
|
||||
|
||||
@@ -9143,6 +9189,168 @@ the <code>echo</code> builtin to be fully conformant.
|
||||
the <samp>--enable-strict-posix-default</samp> to <code>configure</code> when building
|
||||
(see <a href="#Optional-Features">Optional Features</a>).
|
||||
</p>
|
||||
<hr>
|
||||
<span id="Shell-Compatibility-Mode"></span><div class="header">
|
||||
<p>
|
||||
Previous: <a href="#Bash-POSIX-Mode" accesskey="p" rel="prev">Bash POSIX Mode</a>, Up: <a href="#Bash-Features" accesskey="u" rel="up">Bash Features</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Indexes" title="Index" rel="index">Index</a>]</p>
|
||||
</div>
|
||||
<span id="Shell-Compatibility-Mode-1"></span><h3 class="section">6.12 Shell Compatibility Mode</h3>
|
||||
<span id="index-Compatibility-Level"></span>
|
||||
<span id="index-Compatibility-Mode"></span>
|
||||
|
||||
<p>Bash-4.0 introduced the concept of a ‘shell compatibility level’, specified
|
||||
as a set of options to the shopt builtin
|
||||
(<code>compat31</code>,
|
||||
<code>compat32</code>,
|
||||
<code>compat40</code>,
|
||||
<code>compat41</code>,
|
||||
and so on).
|
||||
There is only one current
|
||||
compatibility level – each option is mutually exclusive.
|
||||
The compatibility level is intended to allow users to select behavior
|
||||
from previous versions that is incompatible with newer versions
|
||||
while they migrate scripts to use current features and
|
||||
behavior. It’s intended to be a temporary solution.
|
||||
</p>
|
||||
<p>This section does not mention behavior that is standard for a particular
|
||||
version (e.g., setting <code>compat32</code> means that quoting the rhs of the regexp
|
||||
matching operator quotes special regexp characters in the word, which is
|
||||
default behavior in bash-3.2 and above).
|
||||
</p>
|
||||
<p>If a user enables, say, <code>compat32</code>, it may affect the behavior of other
|
||||
compatibility levels up to and including the current compatibility level.
|
||||
The idea is that each compatibility level controls behavior that changed
|
||||
in that version of Bash,
|
||||
but that behavior may have been present in earlier versions.
|
||||
For instance, the change to use locale-based comparisons with the <code>[[</code>
|
||||
command came in bash-4.1, and earlier versions used ASCII-based comparisons,
|
||||
so enabling <code>compat32</code> will enable ASCII-based comparisons as well.
|
||||
That granularity may not be sufficient for
|
||||
all uses, and as a result users should employ compatibility levels carefully.
|
||||
Read the documentation for a particular feature to find out the
|
||||
current behavior.
|
||||
</p>
|
||||
<p>Bash-4.3 introduced a new shell variable: <code>BASH_COMPAT</code>.
|
||||
The value assigned
|
||||
to this variable (a decimal version number like 4.2, or an integer
|
||||
corresponding to the <code>compat</code><var>NN</var> option, like 42) determines the
|
||||
compatibility level.
|
||||
</p>
|
||||
<p>Starting with bash-4.4, Bash has begun deprecating older compatibility
|
||||
levels.
|
||||
Eventually, the options will be removed in favor of <code>BASH_COMPAT</code>.
|
||||
</p>
|
||||
<p>Bash-5.0 is the final version for which there will be an individual shopt
|
||||
option for the previous version. Users should use <code>BASH_COMPAT</code>
|
||||
on bash-5.0 and later versions.
|
||||
</p>
|
||||
<p>The following table describes the behavior changes controlled by each
|
||||
compatibility level setting.
|
||||
The <code>compat</code><var>NN</var> tag is used as shorthand for setting the
|
||||
compatibility level
|
||||
to <var>NN</var> using one of the following mechanisms.
|
||||
For versions prior to bash-5.0, the compatibility level may be set using
|
||||
the corresponding <code>compat</code><var>NN</var> shopt option.
|
||||
For bash-4.3 and later versions, the <code>BASH_COMPAT</code> variable is preferred,
|
||||
and it is required for bash-5.1 and later versions.
|
||||
</p>
|
||||
<dl compact="compact">
|
||||
<dt><code>compat31</code></dt>
|
||||
<dd><ul>
|
||||
<li> quoting the rhs of the <code>[[</code> command’s regexp matching operator (=~)
|
||||
has no special effect
|
||||
</li></ul>
|
||||
|
||||
</dd>
|
||||
<dt><code>compat32</code></dt>
|
||||
<dd><ul>
|
||||
<li> interrupting a command list such as "a ; b ; c" causes the execution
|
||||
of the next command in the list (in bash-4.0 and later versions,
|
||||
the shell acts as if it received the interrupt, so
|
||||
interrupting one command in a list aborts the execution of the
|
||||
entire list)
|
||||
</li></ul>
|
||||
|
||||
</dd>
|
||||
<dt><code>compat40</code></dt>
|
||||
<dd><ul>
|
||||
<li> the ‘<samp><</samp>’ and ‘<samp>></samp>’ operators to the <code>[[</code> command do not
|
||||
consider the current locale when comparing strings; they use ASCII
|
||||
ordering.
|
||||
Bash versions prior to bash-4.1 use ASCII collation and strcmp(3);
|
||||
bash-4.1 and later use the current locale’s collation sequence and
|
||||
strcoll(3).
|
||||
</li></ul>
|
||||
|
||||
</dd>
|
||||
<dt><code>compat41</code></dt>
|
||||
<dd><ul>
|
||||
<li> in posix mode, <code>time</code> may be followed by options and still be
|
||||
recognized as a reserved word (this is <small>POSIX</small> interpretation 267)
|
||||
</li><li> in posix mode, the parser requires that an even number of single
|
||||
quotes occur in the <var>word</var> portion of a double-quoted ${…}
|
||||
parameter expansion and treats them specially, so that characters within
|
||||
the single quotes are considered quoted
|
||||
(this is <small>POSIX</small> interpretation 221)
|
||||
</li></ul>
|
||||
|
||||
</dd>
|
||||
<dt><code>compat42</code></dt>
|
||||
<dd><ul>
|
||||
<li> the replacement string in double-quoted pattern substitution does not
|
||||
undergo quote removal, as it does in versions after bash-4.2
|
||||
</li><li> in posix mode, single quotes are considered special when expanding
|
||||
the <var>word</var> portion of a double-quoted ${…} parameter expansion
|
||||
and can be used to quote a closing brace or other special character
|
||||
(this is part of <small>POSIX</small> interpretation 221);
|
||||
in later versions, single quotes
|
||||
are not special within double-quoted word expansions
|
||||
</li></ul>
|
||||
|
||||
</dd>
|
||||
<dt><code>compat43</code></dt>
|
||||
<dd><ul>
|
||||
<li> the shell does not print a warning message if an attempt is made to
|
||||
use a quoted compound assignment as an argument to declare
|
||||
(declare -a foo=’(1 2)’). Later versions warn that this usage is
|
||||
deprecated
|
||||
</li><li> word expansion errors are considered non-fatal errors that cause the
|
||||
current command to fail, even in posix mode
|
||||
(the default behavior is to make them fatal errors that cause the shell
|
||||
to exit)
|
||||
</li><li> when executing a shell function, the loop state (while/until/etc.)
|
||||
is not reset, so <code>break</code> or <code>continue</code> in that function will break
|
||||
or continue loops in the calling context. Bash-4.4 and later reset
|
||||
the loop state to prevent this
|
||||
</li></ul>
|
||||
|
||||
</dd>
|
||||
<dt><code>compat44</code></dt>
|
||||
<dd><ul>
|
||||
<li> the shell sets up the values used by <code>BASH_ARGV</code> and <code>BASH_ARGC</code>
|
||||
so they can expand to the shell’s positional parameters even if extended
|
||||
debugging mode is not enabled
|
||||
</li><li> a subshell inherits loops from its parent context, so <code>break</code>
|
||||
or <code>continue</code> will cause the subshell to exit.
|
||||
Bash-5.0 and later reset the loop state to prevent the exit
|
||||
</li><li> variable assignments preceding builtins like <code>export</code> and <code>readonly</code>
|
||||
that set attributes continue to affect variables with the same
|
||||
name in the calling environment even if the shell is not in posix
|
||||
mode
|
||||
</li></ul>
|
||||
|
||||
</dd>
|
||||
<dt><code>compat50 (set using BASH_COMPAT)</code></dt>
|
||||
<dd><ul>
|
||||
<li> Bash-5.1 changed the way <code>$RANDOM</code> is generated to introduce slightly
|
||||
more randomness. If the shell compatibility level is set to 50 or
|
||||
lower, it reverts to the method from bash-5.0 and previous versions,
|
||||
so seeding the random number generator by assigning a value to
|
||||
<code>RANDOM</code> will produce the same sequence as in bash-5.0
|
||||
</li></ul>
|
||||
</dd>
|
||||
</dl>
|
||||
|
||||
<hr>
|
||||
<span id="Job-Control"></span><div class="header">
|
||||
<p>
|
||||
@@ -9245,7 +9453,8 @@ previous job with a ‘<samp>-</samp>’.
|
||||
<p>A job may also be referred to
|
||||
using a prefix of the name used to start it, or using a substring
|
||||
that appears in its command line. For example, ‘<samp>%ce</samp>’ refers
|
||||
to a stopped <code>ce</code> job. Using ‘<samp>%?ce</samp>’, on the
|
||||
to a stopped job whose command name begins with ‘<samp>ce</samp>’.
|
||||
Using ‘<samp>%?ce</samp>’, on the
|
||||
other hand, refers to any job containing the string ‘<samp>ce</samp>’ in
|
||||
its command line. If the prefix or substring matches more than one job,
|
||||
Bash reports an error.
|
||||
@@ -9398,7 +9607,12 @@ the last-executed process substitution, if its process id is the same as
|
||||
<var>$!</var>,
|
||||
and the return status is zero.
|
||||
If the <samp>-n</samp> option is supplied, <code>wait</code> waits for a single job
|
||||
to terminate and returns its exit status.
|
||||
from the list of <var>pids</var> or <var>jobspecs</var> or, if no arguments are
|
||||
supplied, any job,
|
||||
to complete and returns its exit status.
|
||||
If none of the supplied arguments is a child of the shell, or if no arguments
|
||||
are supplied and the shell has no unwaited-for children, the exit status
|
||||
is 127.
|
||||
If the <samp>-p</samp> option is supplied, the process or job identifier of the job
|
||||
for which the exit status is returned is assigned to the variable
|
||||
<var>varname</var> named by the option argument.
|
||||
@@ -10821,10 +11035,19 @@ of the current Readline line is not greater than the length of the prompt
|
||||
plus the screen width.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>clear-display (M-C-l)</code>
|
||||
<span id="index-clear_002ddisplay-_0028M_002dC_002dl_0029"></span>
|
||||
</dt>
|
||||
<dd><p>Clear the screen and, if possible, the terminal’s scrollback buffer,
|
||||
then redraw the current line,
|
||||
leaving the current line at the top of the screen.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>clear-screen (C-l)</code>
|
||||
<span id="index-clear_002dscreen-_0028C_002dl_0029"></span>
|
||||
</dt>
|
||||
<dd><p>Clear the screen and redraw the current line,
|
||||
<dd><p>Clear the screen,
|
||||
then redraw the current line,
|
||||
leaving the current line at the top of the screen.
|
||||
</p>
|
||||
</dd>
|
||||
@@ -10981,6 +11204,17 @@ The history expansion facilities are used to extract the last argument,
|
||||
as if the ‘<samp>!$</samp>’ history expansion had been specified.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>operate-and-get-next (C-o)</code>
|
||||
<span id="index-operate_002dand_002dget_002dnext-_0028C_002do_0029"></span>
|
||||
</dt>
|
||||
<dd><p>Accept the current line for return to the calling application as if a
|
||||
newline had been entered,
|
||||
and fetch the next line relative to the current line from the history
|
||||
for editing.
|
||||
A numeric argument, if supplied, specifies the history entry to use instead
|
||||
of the current line.
|
||||
</p>
|
||||
</dd>
|
||||
</dl>
|
||||
|
||||
<hr>
|
||||
@@ -11697,15 +11931,6 @@ word expansions (see <a href="#Shell-Expansions">Shell Expansions</a>).
|
||||
<dd><p>A synonym for <code>yank-last-arg</code>.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>operate-and-get-next (C-o)</code>
|
||||
<span id="index-operate_002dand_002dget_002dnext-_0028C_002do_0029"></span>
|
||||
</dt>
|
||||
<dd><p>Accept the current line for execution and fetch the next line
|
||||
relative to the current line from the history for editing.
|
||||
A numeric argument, if supplied, specifies the history entry to use instead
|
||||
of the current line.
|
||||
</p>
|
||||
</dd>
|
||||
<dt><code>edit-and-execute-command (C-x C-e)</code>
|
||||
<span id="index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029"></span>
|
||||
</dt>
|
||||
@@ -12477,7 +12702,14 @@ Both <var>first</var> and
|
||||
<var>last</var> may be specified as a string (to locate the most recent
|
||||
command beginning with that string) or as a number (an index into the
|
||||
history list, where a negative number is used as an offset from the
|
||||
current command number). If <var>last</var> is not specified, it is set to
|
||||
current command number).
|
||||
</p>
|
||||
<p>When listing, a <var>first</var> or <var>last</var> of 0 is equivalent to -1
|
||||
and -0 is equivalent to the current command (usually the <code>fc</code>
|
||||
command);
|
||||
otherwise 0 is equivalent to -1 and -0 is invalid.
|
||||
</p>
|
||||
<p>If <var>last</var> is not specified, it is set to
|
||||
<var>first</var>. If <var>first</var> is not specified, it is set to the previous
|
||||
command for editing and -16 for listing. If the <samp>-l</samp> flag is
|
||||
given, the commands are listed on standard output. The <samp>-n</samp> flag
|
||||
@@ -14998,7 +15230,7 @@ Next: <a href="#Function-Index" accesskey="n" rel="next">Function Index</a>, Pre
|
||||
<tr><td></td><td valign="top"><a href="#index-PIPESTATUS"><code>PIPESTATUS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-POSIXLY_005fCORRECT"><code>POSIXLY_CORRECT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-PPID"><code>PPID</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-PROMPT_005fCOMMAND"><code>PROMPT_COMMAND</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-PROMPT_005fCOMMANDS"><code>PROMPT_COMMANDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-PROMPT_005fDIRTRIM"><code>PROMPT_DIRTRIM</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-PS0"><code>PS0</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-PS1"><code>PS1</code></a>:</td><td> </td><td valign="top"><a href="#Bourne-Shell-Variables">Bourne Shell Variables</a></td></tr>
|
||||
@@ -15171,6 +15403,7 @@ Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previ
|
||||
<tr><td></td><td valign="top"><a href="#index-capitalize_002dword-_0028M_002dc_0029"><code>capitalize-word (M-c)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-character_002dsearch-_0028C_002d_005d_0029"><code>character-search (C-])</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-character_002dsearch_002dbackward-_0028M_002dC_002d_005d_0029"><code>character-search-backward (M-C-])</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-clear_002ddisplay-_0028M_002dC_002dl_0029"><code>clear-display (M-C-l)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-clear_002dscreen-_0028C_002dl_0029"><code>clear-screen (C-l)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-complete-_0028TAB_0029"><code>complete (<span class="key">TAB</span>)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-complete_002dcommand-_0028M_002d_0021_0029"><code>complete-command (M-!)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr>
|
||||
@@ -15247,7 +15480,7 @@ Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previ
|
||||
<tr><td></td><td valign="top"><a href="#index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029"><code>non-incremental-reverse-search-history (M-p)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
|
||||
<tr><td colspan="4"> <hr></td></tr>
|
||||
<tr><th id="Function-Index_fn_letter-O">O</th><td></td><td></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-operate_002dand_002dget_002dnext-_0028C_002do_0029"><code>operate-and-get-next (C-o)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-operate_002dand_002dget_002dnext-_0028C_002do_0029"><code>operate-and-get-next (C-o)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-overwrite_002dmode-_0028_0029"><code>overwrite-mode ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr>
|
||||
<tr><td colspan="4"> <hr></td></tr>
|
||||
<tr><th id="Function-Index_fn_letter-P">P</th><td></td><td></td></tr>
|
||||
@@ -15431,6 +15664,8 @@ Previous: <a href="#Function-Index" accesskey="p" rel="prev">Function Index</a>,
|
||||
<tr><td></td><td valign="top"><a href="#index-commands_002c-shell">commands, shell</a>:</td><td> </td><td valign="top"><a href="#Shell-Commands">Shell Commands</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-commands_002c-simple">commands, simple</a>:</td><td> </td><td valign="top"><a href="#Simple-Commands">Simple Commands</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-comments_002c-shell">comments, shell</a>:</td><td> </td><td valign="top"><a href="#Comments">Comments</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-Compatibility-Level">Compatibility Level</a>:</td><td> </td><td valign="top"><a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-Compatibility-Mode">Compatibility Mode</a>:</td><td> </td><td valign="top"><a href="#Shell-Compatibility-Mode">Shell Compatibility Mode</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-completion-builtins">completion builtins</a>:</td><td> </td><td valign="top"><a href="#Programmable-Completion-Builtins">Programmable Completion Builtins</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-configuration">configuration</a>:</td><td> </td><td valign="top"><a href="#Basic-Installation">Basic Installation</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-control-operator">control operator</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
|
||||
@@ -15529,6 +15764,7 @@ Previous: <a href="#Function-Index" accesskey="p" rel="prev">Function Index</a>,
|
||||
<tr><td></td><td valign="top"><a href="#index-Readline_002c-how-to-use">Readline, how to use</a>:</td><td> </td><td valign="top"><a href="#Job-Control-Variables">Job Control Variables</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-redirection">redirection</a>:</td><td> </td><td valign="top"><a href="#Redirections">Redirections</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-reserved-word">reserved word</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-reserved-words">reserved words</a>:</td><td> </td><td valign="top"><a href="#Reserved-Words">Reserved Words</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-restricted-shell">restricted shell</a>:</td><td> </td><td valign="top"><a href="#The-Restricted-Shell">The Restricted Shell</a></td></tr>
|
||||
<tr><td></td><td valign="top"><a href="#index-return-status">return status</a>:</td><td> </td><td valign="top"><a href="#Definitions">Definitions</a></td></tr>
|
||||
<tr><td colspan="4"> <hr></td></tr>
|
||||
|
||||
Reference in New Issue
Block a user