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| author | Chet Ramey <chet.ramey@case.edu> | 2018-11-23 15:32:57 -0500 |
|---|---|---|
| committer | Chet Ramey <chet.ramey@case.edu> | 2018-11-23 15:32:57 -0500 |
| commit | 2ae59c1134a75d5778997b7202b15b0586283042 (patch) | |
| tree | 6a0fa496d41b222f5f69e3640d84932fb7a84778 /doc/bashref.html | |
| parent | 2f5dfe5a18b4670eb4cea32c1c76295eb70a8865 (diff) | |
| download | bash-5.0-beta2.tar.gz | |
bash-5.0-beta2 releasebash-5.0-beta2
Diffstat (limited to 'doc/bashref.html')
| -rw-r--r-- | doc/bashref.html | 76 |
1 files changed, 57 insertions, 19 deletions
diff --git a/doc/bashref.html b/doc/bashref.html index 13d9294c..e5e150b3 100644 --- a/doc/bashref.html +++ b/doc/bashref.html @@ -1,9 +1,9 @@ <!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, 7 August 2018). +the Bash shell (version 5.0, 9 November 2018). -This is Edition 5.0, last updated 7 August 2018, +This is Edition 5.0, last updated 9 November 2018, of The GNU Bash Reference Manual, for Bash, Version 5.0. @@ -284,10 +284,10 @@ Next: <a href="#Introduction" accesskey="n" rel="next">Introduction</a>, Previou <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, 7 August 2018). +the Bash shell (version 5.0, 9 November 2018). 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 7 August 2018, +<p>This is Edition 5.0, last updated 9 November 2018, of <cite>The GNU Bash Reference Manual</cite>, for <code>Bash</code>, Version 5.0. </p> @@ -2222,8 +2222,8 @@ to the filename used to invoke Bash, as given by argument zero. At shell startup, set to the absolute 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 command, -after expansion. +Subsequently, expands to the last argument to the previous simple +command executed in the foreground, after expansion. Also set to the full pathname used to invoke each command executed and placed in the environment exported to that command. When checking mail, this parameter holds the name of the mail file. @@ -4455,19 +4455,22 @@ false. </dd> <dt>3 arguments</dt> <dd><p>The following conditions are applied in the order listed. -If the second argument is one of the binary conditional +</p> +<ol> +<li> If the second argument is one of the binary conditional operators (see <a href="#Bash-Conditional-Expressions">Bash Conditional Expressions</a>), the result of the expression is the result of the binary test using the first and third arguments as operands. The ‘<samp>-a</samp>’ and ‘<samp>-o</samp>’ operators are considered binary operators when there are three arguments. -If the first argument is ‘<samp>!</samp>’, the value is the negation of +</li><li> If the first argument is ‘<samp>!</samp>’, the value is the negation of the two-argument test using the second and third arguments. -If the first argument is exactly ‘<samp>(</samp>’ and the third argument is +</li><li> If the first argument is exactly ‘<samp>(</samp>’ and the third argument is exactly ‘<samp>)</samp>’, the result is the one-argument test of the second argument. -Otherwise, the expression is false. -</p> +</li><li> Otherwise, the expression is false. +</li></ol> + </dd> <dt>4 arguments</dt> <dd><p>If the first argument is ‘<samp>!</samp>’, the result is the negation of @@ -5300,7 +5303,7 @@ The prompt is displayed only if input is coming from a terminal. <dt><code>-r</code></dt> <dd><p>If this option is given, backslash does not act as an escape character. The backslash is considered to be part of the line. -In particular, a backslash-newline pair may not be used as a line +In particular, a backslash-newline pair may not then be used as a line continuation. </p> </dd> @@ -6024,6 +6027,7 @@ The shell always postpones exiting if any jobs are stopped. <dd><p>If set, Bash checks the window size after each external (non-builtin) command and, if necessary, updates the values of <code>LINES</code> and <code>COLUMNS</code>. +This option is enabled by default. </p> </dd> <dt><code>cmdhist</code></dt> @@ -6289,6 +6293,13 @@ the same name that exists at a previous scope before any new value is assigned. The <var>nameref</var> attribute is not inherited. </p> </dd> +<dt><code>localvar_unset</code></dt> +<dd><p>If set, calling <code>unset</code> on local variables in previous function scopes +marks them so subsequent lookups find them unset until that function +returns. This is identical to the behavior of unsetting local variables +at the current function scope. +</p> +</dd> <dt><code>login_shell</code></dt> <dd><p>The shell sets this option if it is started as a login shell (see <a href="#Invoking-Bash">Invoking Bash</a>). @@ -6331,6 +6342,13 @@ files to expand to a null string, rather than themselves. This option is enabled by default. </p> </dd> +<dt><code>progcomp_alias</code></dt> +<dd><p>If set, and programmable completion is enabled, Bash treats a command +name that doesn’t have any completions as a possible alias and attempts +alias expansion. If it has an alias, Bash attempts programmable +completion using the command word resulting from the expanded alias. +</p> +</dd> <dt><code>promptvars</code></dt> <dd><p>If set, prompt strings undergo parameter expansion, command substitution, arithmetic @@ -8108,9 +8126,13 @@ Next: <a href="#Shell-Arithmetic" accesskey="n" rel="next">Shell Arithmetic</a>, <a name="index-expressions_002c-conditional"></a> <p>Conditional expressions are used by the <code>[[</code> compound command -and the <code>test</code> and <code>[</code> builtin commands. +and the <code>test</code> and <code>[</code> builtin commands. The <code>test</code> +and <code>[</code> commands determine their behavior based on the number +of arguments; see the descriptions of those commands for any other +command-specific actions. </p> -<p>Expressions may be unary or binary. +<p>Expressions may be unary or binary, +and are formed from the following primaries. Unary expressions are often used to examine the status of a file. There are string operators and numeric comparison operators as well. Bash handles several filenames specially when they are used in @@ -8464,10 +8486,11 @@ unless the <code>expand_aliases</code> shell option is set using <code>shopt</code> (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>). </p> <p>The rules concerning the definition and use of aliases are -somewhat confusing. Bash -always reads at least one complete line -of input before executing any -of the commands on that line. Aliases are expanded when a +somewhat confusing. Bash +always reads at least one complete line of input, +and all lines that make up a compound command, +before executing any of the commands on that line or the compound command. +Aliases are expanded when a command is read, not when it is executed. Therefore, an alias definition appearing on the same line as another command does not take effect until the next line of input is read. @@ -9113,6 +9136,11 @@ the <samp>-e</samp> option from the parent shell. When the <code>inherit_errexit</code> option is not enabled, Bash clears the <samp>-e</samp> option in such subshells. +</li><li> Enabling <small>POSIX</small> mode has the effect of setting the +<code>shift_verbose</code> option, so numeric arguments to <code>shift</code> +that exceed the number of positional parameters will result in an +error message. + </li><li> When the <code>alias</code> builtin displays alias definitions, it does not display them with a leading ‘<samp>alias </samp>’ unless the <samp>-p</samp> option is supplied. @@ -9129,6 +9157,12 @@ constructed from <code>$PWD</code> and the directory name supplied as an argumen does not refer to an existing directory, <code>cd</code> will fail instead of falling back to <var>physical</var> mode. +</li><li> When the <code>cd</code> builtin cannot change a directory because the +length of the pathname +constructed from <code>$PWD</code> and the directory name supplied as an argument +exceeds <var>PATH_MAX</var> when all symbolic links are expanded, <code>cd</code> will +fail instead of attempting to use only the supplied directory name. + </li><li> The <code>pwd</code> builtin verifies that the value it prints is the same as the current directory, even if it is not asked to check the file system with the <samp>-P</samp> option. @@ -10195,7 +10229,7 @@ If this variable has not been given a value, the characters <tt class="key">ESC< <dt><code>keymap</code></dt> <dd><a name="index-keymap"></a> <p>Sets Readline’s idea of the current keymap for key binding commands. -Acceptable <code>keymap</code> names are +Built-in <code>keymap</code> names are <code>emacs</code>, <code>emacs-standard</code>, <code>emacs-meta</code>, @@ -10206,6 +10240,7 @@ Acceptable <code>keymap</code> names are <code>vi-insert</code>. <code>vi</code> is equivalent to <code>vi-command</code> (<code>vi-move</code> is also a synonym); <code>emacs</code> is equivalent to <code>emacs-standard</code>. +Applications may add additional names. The default value is <code>emacs</code>. The value of the <code>editing-mode</code> variable also affects the default keymap. @@ -11840,6 +11875,9 @@ If no compspec is found for the full pathname, an attempt is made to find a compspec for the portion following the final slash. If those searches do not result in a compspec, any compspec defined with the <samp>-D</samp> option to <code>complete</code> is used as the default. +If there is no default compspec, Bash attempts alias expansion +on the command word as a final resort, and attempts to find a compspec +for the command word from any successful expansion </p> <p>Once a compspec has been found, it is used to generate the list of matching words. |