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<a name="Shell-Builtin-Commands"></a>
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<a name="Shell-Builtin-Commands-1"></a>
<h1 class="chapter">17 Shell Builtin Commands</h1>
<a name="index-builtin-commands"></a>
<a name="index-commands_002c-builtin"></a>
<p>Some shell builtin commands take options as described in individual
entries; these are often referred to in the list below as ‘<tt>flags</tt>’ to
avoid confusion with shell options, which may also have an effect on the
behaviour of builtin commands. In this introductory section,
‘<tt>option</tt>’ always has the meaning of an option to a command that should
be familiar to most command line users.
</p>
<p>Typically, options are single letters preceded by a hyphen (<tt>-</tt>).
Options that take an argument accept it either immediately following the
option letter or after white space, for example ‘<tt>print -C3 *</tt>’ or
‘<tt>print -C 3 *</tt>’ are equivalent. Arguments to options are not the
same as arguments to the command; the documentation indicates which is
which. Options that do not take an argument may be combined in a single
word, for example ‘<tt>print -ca *</tt>’ and ‘<tt>print -c -a *</tt>’ are
equivalent.
</p>
<p>Some shell builtin commands also take options that begin with ‘<tt>+</tt>’
instead of ‘<tt>-</tt>’. The list below makes clear which commands these
are.
</p>
<p>Options (together with their individual arguments, if any) must appear
in a group before any non-option arguments; once the first non-option
argument has been found, option processing is terminated.
</p>
<p>All builtin commands other than precommand modifiers, even those that
have no options, can be given the argument ‘<tt>-</tt><tt>-</tt>’ to terminate option
processing. This indicates that the following words are non-option
arguments, but is otherwise ignored. This is useful in cases where
arguments to the command may begin with ‘<tt>-</tt>’. For historical
reasons, most builtin commands also recognize a single ‘<tt>-</tt>’ in a
separate word for this purpose; note that this is less standard and
use of ‘<tt>-</tt><tt>-</tt>’ is recommended.
</p>
<dl compact="compact">
<dt><tt>-</tt> <var>simple command</var></dt>
<dd><p>See <a href="Shell-Grammar.html#Precommand-Modifiers">Precommand Modifiers</a>.
</p>
<a name="index-_002e"></a>
</dd>
<dt><tt>.</tt> <var>file</var> [ <var>arg</var> ... ]</dt>
<dd><p>Read commands from <var>file</var> and execute them in the current shell
environment.
</p>
<p>If <var>file</var> does not contain a slash, or if <tt>PATH_DIRS</tt> is set,
the shell looks in the components of <tt>$path</tt> to find the directory
containing <var>file</var>. Files in the current directory are not read
unless ‘<tt>.</tt>’ appears somewhere in <tt>$path</tt>. If a file named
‘<var>file</var><tt>.zwc</tt>’ is found, is newer than <var>file</var>, and is the
compiled form (created with the <tt>zcompile</tt> builtin) of <var>file</var>,
then commands are read from that file instead of <var>file</var>.
</p>
<p>If any arguments <var>arg</var> are given,
they become the positional parameters; the old positional
parameters are restored when the <var>file</var> is done executing.
However, if no arguments are given,
the positional parameters remain those of the calling context,
and no restoring is done.
</p>
<p>If <var>file</var> was not found the return status is 127; if <var>file</var> was found
but contained a syntax error the return status is 126; else the return
status is the exit status of the last command executed.
</p>
<a name="index-_003a"></a>
<a name="index-expanding-parameters"></a>
<a name="index-parameters_002c-expanding"></a>
<a name="index-doing-nothing"></a>
</dd>
<dt><tt>:</tt> [ <var>arg</var> ... ]</dt>
<dd><p>This command does nothing, although normal argument expansions is performed
which may have effects on shell parameters. A zero exit status is returned.
</p>
<a name="index-alias"></a>
<a name="index-aliases_002c-defining"></a>
<a name="index-aliases_002c-listing"></a>
</dd>
<dt><tt>alias</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>gmrsL</tt> ] [ <var>name</var>[<tt>=</tt><var>value</var>] ... ]</dt>
<dd><p>For each <var>name</var> with a corresponding <var>value</var>, define an alias
with that value. A trailing space in <var>value</var> causes the next word
to be checked for alias expansion. If the <tt>-g</tt> flag is present,
define a global alias; global aliases are expanded even if they do not
occur in command position.
</p>
<p>If the <tt>-s</tt> flag is present, define a suffix alias: if the command
word on a command line is in the form ‘<var>text</var><tt>.</tt><var>name</var>’, where
<var>text</var> is any non-empty string, it is replaced by the text
‘<var>value</var> <var>text</var><tt>.</tt><var>name</var>’. Note that <var>name</var> is treated as
a literal string, not a pattern. A trailing space in <var>value</var> is not
special in this case. For example,
</p>
<div class="example">
<pre class="example">alias -s ps=gv
</pre></div>
<p>will cause the command ‘<tt>*.ps</tt>’ to be expanded to ‘<tt>gv *.ps</tt>’. As
alias expansion is carried out earlier than globbing, the ‘<tt>*.ps</tt>’ will
then be expanded. Suffix aliases constitute a different name space from
other aliases (so in the above example it is still possible
to create an alias for the command <tt>ps</tt>) and the two sets are never
listed together.
</p>
<p>For each <var>name</var> with no <var>value</var>,
print the value of <var>name</var>, if any. With no arguments, print all
currently defined aliases other than suffix aliases. If the <tt>-m</tt> flag
is given the arguments are taken as patterns (they should be quoted to
preserve them from being interpreted as glob patterns), and the aliases
matching these patterns are printed. When printing aliases and one of
the <tt>-g</tt>, <tt>-r</tt> or <tt>-s</tt> flags is present, restrict the printing to
global, regular or suffix aliases, respectively; a regular alias is one
which is neither a global nor a suffix alias. Using ‘<tt>+</tt>’
instead of ‘<tt>-</tt>’, or ending the option list with a single
‘<tt>+</tt>’, prevents the values of the aliases from being printed.
</p>
<p>If the <tt>-L</tt> flag is present, then print each
alias in a manner suitable for putting in a startup script. The exit
status is nonzero if a <var>name</var> (with no <var>value</var>) is given for
which no alias has been defined.
</p>
<p>For more on aliases, include common problems, see
<a href="Shell-Grammar.html#Aliasing">Aliasing</a>.
</p>
<a name="index-autoload"></a>
<a name="index-functions_002c-autoloading-1"></a>
<a name="index-autoloading-functions-1"></a>
</dd>
<dt><tt>autoload</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>RTUXdkmrtWz</tt> ] [ <tt>-w</tt> ] [ <var>name</var> ... ]</dt>
<dd><a name="index-fpath_002c-searching"></a>
<p>See the section ‘Autoloading Functions’ in <a href="Functions.html#Functions">Functions</a> for full details. The <tt>fpath</tt> parameter
will be searched to find the function definition when the function is
first referenced.
</p>
<p>If <var>name</var> consists of an absolute path, the function is defined to
load from the file given (searching as usual for dump files in the given
location). The name of the function is the basename (non-directory
part) of the file. It is normally an error if the function is not found
in the given location; however, if the option <tt>-d</tt> is given, searching
for the function defaults to <tt>$fpath</tt>. If a function is loaded by
absolute path, any functions loaded from it that are marked for
<tt>autoload</tt> without an absolute path have the load path of the parent
function temporarily prepended to <tt>$fpath</tt>.
</p>
<p>If the option <tt>-r</tt> or <tt>-R</tt> is given, the function is searched for
immediately and the location is recorded internally for use when the
function is executed; a relative path is expanded using the value of
<tt>$PWD</tt>. This protects against a change to <tt>$fpath</tt> after the call
to <tt>autoload</tt>. With <tt>-r</tt>, if the function is not found, it is
silently left unresolved until execution; with <tt>-R</tt>, an error message
is printed and command processing aborted immediately the search fails,
i.e. at the <tt>autoload</tt> command rather than at function execution..
</p>
<p>The flag <tt>-X</tt> may be used only inside a shell function. It causes the
calling function to be marked for autoloading and then immediately
loaded and executed, with the current array of positional parameters as
arguments. This replaces the previous definition of the function. If
no function definition is found, an error is printed and the function
remains undefined and marked for autoloading. If an argument is given,
it is used as a directory (i.e. it does not include the name of the
function) in which the function is to be found; this may be combined
with the <tt>-d</tt> option to allow the function search to default to <tt>$fpath</tt>
if it is not in the given location.
</p>
<p>The flag <tt>+X</tt> attempts to load each <var>name</var> as an autoloaded function,
but does <em>not</em> execute it. The exit status is zero (success) if the
function was not previously defined <em>and</em> a definition for it was found.
This does <em>not</em> replace any existing definition of the function. The
exit status is nonzero (failure) if the function was already defined or
when no definition was found. In the latter case the function remains
undefined and marked for autoloading. If ksh-style autoloading is
enabled, the function created will contain the contents of the file
plus a call to the function itself appended to it, thus giving normal
ksh autoloading behaviour on the first call to the function.
If the <tt>-m</tt> flag is also given each <var>name</var> is treated as a
pattern and all functions already marked for autoload that match the
pattern are loaded.
</p>
<p>With the <tt>-t</tt> flag, turn on execution tracing; with <tt>-T</tt>, turn on
execution tracing only for the current function, turning it off on entry
to any called functions that do not also have tracing enabled.
</p>
<p>With the <tt>-U</tt> flag, alias expansion is suppressed when the function is
loaded.
</p>
<p>With the <tt>-w</tt> flag, the <var>name</var>s are taken as names of files compiled
with the <tt>zcompile</tt> builtin, and all functions defined in them are
marked for autoloading.
</p>
<p>The flags <tt>-z</tt> and <tt>-k</tt> mark the function to be autoloaded using the
zsh or ksh style, as if the option <tt>KSH_AUTOLOAD</tt> were unset or were
set, respectively. The flags override the setting of the option at the
time the function is loaded.
</p>
<p>Note that the <tt>autoload</tt> command makes no attempt to ensure the
shell options set during the loading or execution of the file have
any particular value. For this, the <tt>emulate</tt> command can be used:
</p>
<div class="example">
<pre class="example">emulate zsh -c 'autoload -Uz <var>func</var>'
</pre></div>
<p>arranges that when <var>func</var> is loaded the shell is in native <tt>zsh</tt>
emulation, and this emulation is also applied when <var>func</var> is run.
</p>
<p>Some of the functions of <tt>autoload</tt> are also provided by <tt>functions
-u</tt> or <tt>functions -U</tt>, but <tt>autoload</tt> is a more comprehensive
interface.
</p>
<a name="index-bg"></a>
<a name="index-jobs_002c-backgrounding"></a>
</dd>
<dt><tt>bg</tt> [ <var>job</var> ... ]</dt>
<dt><var>job</var> ... <tt>&</tt></dt>
<dd><p>Put each specified <var>job</var> in the background,
or the current job if none is specified.
</p>
</dd>
<dt><tt>bindkey</tt></dt>
<dd><p>See <a href="Zsh-Line-Editor.html#Zle-Builtins">Zle Builtins</a>.
</p>
<a name="index-break"></a>
<a name="index-exiting-loops"></a>
<a name="index-loops_002c-exiting"></a>
</dd>
<dt><tt>break</tt> [ <var>n</var> ]</dt>
<dd><p>Exit from an enclosing <tt>for</tt>, <tt>while</tt>,
<tt>until</tt>, <tt>select</tt> or <tt>repeat</tt> loop. If an arithmetic expression <var>n</var>
is specified, then break <var>n</var> levels instead of just one.
</p>
<a name="index-builtin-1"></a>
</dd>
<dt><tt>builtin</tt> <var>name</var> [ <var>args</var> ... ]</dt>
<dd><p>Executes the builtin <var>name</var>, with the given <var>args</var>.
</p>
<a name="index-bye"></a>
</dd>
<dt><tt>bye</tt></dt>
<dd><p>Same as <tt>exit</tt>.
</p>
</dd>
<dt><tt>cap</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcap-Module">The zsh/cap Module</a>.
</p>
<a name="index-cd"></a>
<a name="index-directories_002c-changing"></a>
</dd>
<dt><tt>cd</tt> [ <tt>-qsLP</tt> ] [ <var>arg</var> ]</dt>
<dt><tt>cd</tt> [ <tt>-qsLP</tt> ] <var>old</var> <var>new</var></dt>
<dt><tt>cd</tt> [ <tt>-qsLP</tt> ] {<tt>+</tt>|<tt>-</tt>}<var>n</var></dt>
<dd><p>Change the current directory. In the first form, change the
current directory to <var>arg</var>, or to the value of <tt>$HOME</tt> if
<var>arg</var> is not specified. If <var>arg</var> is ‘<tt>-</tt>’, change to the
previous directory.
</p>
<p>Otherwise, if <var>arg</var> begins with a slash, attempt to change to the
directory given by <var>arg</var>.
</p>
<p>If <var>arg</var> does not begin with a slash, the behaviour depends on whether
the current directory ‘<tt>.</tt>’ occurs in the list of directories contained
in the shell parameter <tt>cdpath</tt>. If it does not, first attempt to change
to the directory <var>arg</var> under the current directory, and if that fails
but <tt>cdpath</tt> is set and contains at least one element attempt to change
to the directory <var>arg</var> under each component of <tt>cdpath</tt> in turn until
successful. If ‘<tt>.</tt>’ occurs in <tt>cdpath</tt>, then <tt>cdpath</tt> is searched
strictly in order so that ‘<tt>.</tt>’ is only tried at the appropriate point.
</p>
<p>The order of testing <tt>cdpath</tt> is modified if the option <tt>POSIX_CD</tt>
is set, as described in the documentation for the option.
</p>
<p>If no directory is found, the option <tt>CDABLE_VARS</tt> is set, and a
parameter named <var>arg</var> exists whose value begins with a slash, treat its
value as the directory. In that case, the parameter is added to the named
directory hash table.
</p>
<p>The second form of <tt>cd</tt> substitutes the string <var>new</var>
for the string <var>old</var> in the name of the current directory,
and tries to change to this new directory.
</p>
<p>The third form of <tt>cd</tt> extracts an entry from the directory
stack, and changes to that directory. An argument of the form
‘<tt>+</tt><var>n</var>’ identifies a stack entry by counting from the left
of the list shown by the <tt>dirs</tt> command, starting with zero.
An argument of the form ‘<tt>-</tt><var>n</var>’ counts from the right.
If the <tt>PUSHD_MINUS</tt> option is set, the meanings of ‘<tt>+</tt>’
and ‘<tt>-</tt>’ in this context are swapped.
</p>
<p>If the <tt>-q</tt> (quiet) option is specified, the hook function <tt>chpwd</tt>
and the functions in the array <tt>chpwd_functions</tt> are not called.
This is useful for calls to <tt>cd</tt> that do not change the environment
seen by an interactive user.
</p>
<p>If the <tt>-s</tt> option is specified, <tt>cd</tt> refuses to change the current
directory if the given pathname contains symlinks. If the <tt>-P</tt> option
is given or the <tt>CHASE_LINKS</tt> option is set, symbolic links are resolved
to their true values. If the <tt>-L</tt> option is given symbolic links are
retained in the directory (and not resolved) regardless of the state of
the <tt>CHASE_LINKS</tt> option.
</p>
<a name="index-chdir"></a>
</dd>
<dt><tt>chdir</tt></dt>
<dd><p>Same as <tt>cd</tt>.
</p>
</dd>
<dt><tt>clone</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fclone-Module">The zsh/clone Module</a>.
</p>
<a name="index-command-1"></a>
</dd>
<dt><tt>command</tt> [ <tt>-pvV</tt> ] <var>simple command</var></dt>
<dd><p>The simple command argument is taken as an external command instead of
a function or builtin and is executed. If the <tt>POSIX_BUILTINS</tt> option
is set, builtins will also be executed but certain special properties
of them are suppressed. The <tt>-p</tt> flag causes a default path to be
searched instead of that in <tt>$path</tt>. With the <tt>-v</tt> flag, <tt>command</tt>
is similar to <tt>whence</tt> and with <tt>-V</tt>, it is equivalent to <tt>whence
-v</tt>.
</p>
<p>See also <a href="Shell-Grammar.html#Precommand-Modifiers">Precommand Modifiers</a>.
</p>
</dd>
<dt><tt>comparguments</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
</dd>
<dt><tt>compcall</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcompctl-Module">The zsh/compctl Module</a>.
</p>
</dd>
<dt><tt>compctl</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcompctl-Module">The zsh/compctl Module</a>.
</p>
</dd>
<dt><tt>compdescribe</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
</dd>
<dt><tt>compfiles</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
</dd>
<dt><tt>compgroups</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
</dd>
<dt><tt>compquote</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
</dd>
<dt><tt>comptags</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
</dd>
<dt><tt>comptry</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
</dd>
<dt><tt>compvalues</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcomputil-Module">The zsh/computil Module</a>.
</p>
<a name="index-continue"></a>
<a name="index-loops_002c-continuing"></a>
<a name="index-continuing-loops"></a>
</dd>
<dt><tt>continue</tt> [ <var>n</var> ]</dt>
<dd><p>Resume the next iteration of the enclosing
<tt>for</tt>, <tt>while</tt>, <tt>until</tt>, <tt>select</tt> or
<tt>repeat</tt> loop. If an arithmetic expression <var>n</var> is specified, break out of
<var>n</var>-1 loops and resume at the <var>n</var>th enclosing loop.
</p>
<a name="index-declare"></a>
</dd>
<dt><tt>declare</tt></dt>
<dd><p>Same as <tt>typeset</tt>.
</p>
<a name="index-dirs"></a>
<a name="index-directory-stack_002c-printing"></a>
</dd>
<dt><tt>dirs</tt> [ <tt>-c</tt> ] [ <var>arg</var> ... ]</dt>
<dt><tt>dirs</tt> [ <tt>-lpv</tt> ]</dt>
<dd><p>With no arguments, print the contents of the directory stack.
Directories are added to this stack with the <tt>pushd</tt> command,
and removed with the <tt>cd</tt> or <tt>popd</tt> commands.
If arguments are specified, load them onto the directory stack,
replacing anything that was there, and push the current directory
onto the stack.
</p>
<dl compact="compact">
<dt><tt>-c</tt></dt>
<dd><p>clear the directory stack.
</p>
</dd>
<dt><tt>-l</tt></dt>
<dd><p>print directory names in full instead of using of using <tt>~</tt> expressions (<a href="Expansion.html#Filename-Expansion">Filename Expansion</a>).
</p>
</dd>
<dt><tt>-p</tt></dt>
<dd><p>print directory entries one per line.
</p>
</dd>
<dt><tt>-v</tt></dt>
<dd><p>number the directories in the stack when printing.
</p>
</dd>
</dl>
<a name="index-disable"></a>
<a name="index-disabling-commands"></a>
<a name="index-commands_002c-disabling"></a>
</dd>
<dt><tt>disable</tt> [ <tt>-afmprs</tt> ] <var>name</var> ...</dt>
<dd><p>Temporarily disable the <var>name</var>d hash table elements or patterns. The default
is to disable builtin commands. This allows you to use an external
command with the same name as a builtin command. The <tt>-a</tt> option
causes <tt>disable</tt> to act on regular or global aliases. The <tt>-s</tt>
option causes <tt>disable</tt> to act on suffix aliases. The <tt>-f</tt> option causes
<tt>disable</tt> to act on shell functions. The <tt>-r</tt> options causes
<tt>disable</tt> to act on reserved words. Without arguments all disabled
hash table elements from the corresponding hash table are printed.
With the <tt>-m</tt> flag the arguments are taken as patterns (which should be
quoted to prevent them from undergoing filename expansion), and all hash
table elements from the corresponding hash table matching these patterns
are disabled. Disabled objects can be enabled with the <tt>enable</tt>
command.
</p>
<p>With the option <tt>-p</tt>, <var>name</var> ... refer to elements of the
shell’s pattern syntax as described in <a href="Expansion.html#Filename-Generation">Filename Generation</a>.
Certain elements can be disabled separately, as given below.
</p>
<p>Note that patterns
not allowed by the current settings for the options <tt>EXTENDED_GLOB</tt>,
<tt>KSH_GLOB</tt> and <tt>SH_GLOB</tt> are never enabled, regardless of the
setting here. For example, if <tt>EXTENDED_GLOB</tt> is not active,
the pattern <tt>^</tt> is ineffective even if ‘<tt>disable -p "^"</tt>’ has
not been issued. The list below indicates any option settings
that restrict the use of the pattern. It should be noted that
setting <tt>SH_GLOB</tt> has a wider effect than merely disabling patterns
as certain expressions, in particular those involving parentheses,
are parsed differently.
</p>
<p>The following patterns may be disabled; all
the strings need quoting on the command line to prevent them from
being interpreted immediately as patterns and the patterns are
shown below in single quotes as a reminder.
</p>
<dl compact="compact">
<dt><tt>'?'</tt></dt>
<dd><p>The pattern character <tt>?</tt> wherever it occurs, including when preceding
a parenthesis with <tt>KSH_GLOB</tt>.
</p>
</dd>
<dt><tt>'*'</tt></dt>
<dd><p>The pattern character <tt>*</tt> wherever it occurs, including recursive
globbing and when preceding a parenthesis with <tt>KSH_GLOB</tt>.
</p>
</dd>
<dt><tt>'['</tt></dt>
<dd><p>Character classes.
</p>
</dd>
<dt><tt>'<'</tt> (<tt>NO_SH_GLOB</tt>)</dt>
<dd><p>Numeric ranges.
</p>
</dd>
<dt><tt>'|'</tt> (<tt>NO_SH_GLOB</tt>)</dt>
<dd><p>Alternation in grouped patterns, case statements, or KSH_GLOB
parenthesised expressions.
</p>
</dd>
<dt><tt>'('</tt> (<tt>NO_SH_GLOB</tt>)</dt>
<dd><p>Grouping using single parentheses. Disabling this does not disable the
use of parentheses for <tt>KSH_GLOB</tt> where they are introduced by a
special character, nor for glob qualifiers (use ‘<tt>setopt
NO_BARE_GLOB_QUAL</tt>’ to disable glob qualifiers that use parentheses
only).
</p>
</dd>
<dt><tt>'~'</tt> (<tt>EXTENDED_GLOB</tt>)</dt>
<dd><p>Exclusion in the form <var>A</var><tt>~</tt><var>B</var>.
</p>
</dd>
<dt><tt>'^'</tt> (<tt>EXTENDED_GLOB</tt>)</dt>
<dd><p>Exclusion in the form <var>A</var><tt>^</tt><var>B</var>.
</p>
</dd>
<dt><tt>'#'</tt> (<tt>EXTENDED_GLOB</tt>)</dt>
<dd><p>The pattern character <tt>#</tt> wherever it occurs, both for
repetition of a previous pattern and for indicating globbing flags.
</p>
</dd>
<dt><tt>'?('</tt> (<tt>KSH_GLOB</tt>)</dt>
<dd><p>The grouping form <tt>?(</tt><var>...</var><tt>)</tt>. Note this is also
disabled if <tt>'?'</tt> is disabled.
</p>
</dd>
<dt><tt>'*('</tt> (<tt>KSH_GLOB</tt>)</dt>
<dd><p>The grouping form <tt>*(</tt><var>...</var><tt>)</tt>. Note this is also
disabled if <tt>'*'</tt> is disabled.
</p>
</dd>
<dt><tt>'+('</tt> (<tt>KSH_GLOB</tt>)</dt>
<dd><p>The grouping form <tt>+(</tt><var>...</var><tt>)</tt>.
</p>
</dd>
<dt><tt>'!('</tt> (<tt>KSH_GLOB</tt>)</dt>
<dd><p>The grouping form <tt>!(</tt><var>...</var><tt>)</tt>.
</p>
</dd>
<dt><tt>'@('</tt> (<tt>KSH_GLOB</tt>)</dt>
<dd><p>The grouping form <tt>@(</tt><var>...</var><tt>)</tt>.
</p>
</dd>
</dl>
<a name="index-disown"></a>
<a name="index-jobs_002c-disowning-1"></a>
</dd>
<dt><tt>disown</tt> [ <var>job</var> ... ]</dt>
<dt><var>job</var> ... <tt>&|</tt></dt>
<dt><var>job</var> ... <tt>&!</tt></dt>
<dd><p>Remove the specified <var>job</var>s from the job table; the shell will
no longer report their status, and will not complain if you
try to exit an interactive shell with them running or stopped.
If no <var>job</var> is specified, disown the current job.
</p>
<p>If the <var>job</var>s are currently stopped and the <tt>AUTO_CONTINUE</tt> option
is not set, a warning is printed containing information about how to
make them running after they have been disowned. If one of the latter
two forms is used, the <var>job</var>s will automatically be made running,
independent of the setting of the <tt>AUTO_CONTINUE</tt> option.
</p>
<a name="index-echo"></a>
</dd>
<dt><tt>echo</tt> [ <tt>-neE</tt> ] [ <var>arg</var> ... ]</dt>
<dd><p>Write each <var>arg</var> on the standard output, with a space separating
each one.
If the <tt>-n</tt> flag is not present, print a newline at the end.
<tt>echo</tt> recognizes the following escape sequences:
</p>
<dl compact="compact">
<dt><tt>\a</tt></dt>
<dd><p>bell character
</p></dd>
<dt><tt>\b</tt></dt>
<dd><p>backspace
</p></dd>
<dt><tt>\c</tt></dt>
<dd><p>suppress subsequent characters and final newline
</p></dd>
<dt><tt>\e</tt></dt>
<dd><p>escape
</p></dd>
<dt><tt>\f</tt></dt>
<dd><p>form feed
</p></dd>
<dt><tt>\n</tt></dt>
<dd><p>linefeed (newline)
</p></dd>
<dt><tt>\r</tt></dt>
<dd><p>carriage return
</p></dd>
<dt><tt>\t</tt></dt>
<dd><p>horizontal tab
</p></dd>
<dt><tt>\v</tt></dt>
<dd><p>vertical tab
</p></dd>
<dt><tt>\\</tt></dt>
<dd><p>backslash
</p></dd>
<dt><tt>\0</tt><var>NNN</var></dt>
<dd><p>character code in octal
</p></dd>
<dt><tt>\x</tt><var>NN</var></dt>
<dd><p>character code in hexadecimal
</p></dd>
<dt><tt>\u</tt><var>NNNN</var></dt>
<dd><p>unicode character code in hexadecimal
</p></dd>
<dt><tt>\U</tt><var>NNNNNNNN</var></dt>
<dd><p>unicode character code in hexadecimal
</p></dd>
</dl>
<a name="index-BSD_005fECHO_002c-use-of"></a>
<p>The <tt>-E</tt> flag, or the <tt>BSD_ECHO</tt> option, can be used to disable
these escape sequences. In the latter case, <tt>-e</tt> flag can be used to
enable them.
</p>
<p>Note that for standards compliance a double dash does not terminate
option processing; instead, it is printed directly. However, a
single dash does terminate option processing, so the first dash,
possibly following options, is not printed, but everything following it
is printed as an argument. The single dash behaviour is different
from other shells. For a more portable way of printing text, see
<tt>printf</tt>, and for a more controllable way of printing text within zsh,
see <tt>print</tt>.
</p>
</dd>
<dt><tt>echotc</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002ftermcap-Module">The zsh/termcap Module</a>.
</p>
</dd>
<dt><tt>echoti</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fterminfo-Module">The zsh/terminfo Module</a>.
</p>
<a name="index-emulate"></a>
<a name="index-compatibility_002c-sh"></a>
<a name="index-compatibility_002c-ksh"></a>
<a name="index-compatibility_002c-csh"></a>
<a name="index-sh_002c-compatibility"></a>
<a name="index-ksh_002c-compatibility"></a>
<a name="index-csh_002c-compatibility"></a>
</dd>
<dt><tt>emulate</tt> [ <tt>-lLR</tt> ] [ {<tt>zsh</tt>|<tt>sh</tt>|<tt>ksh</tt>|<tt>csh</tt>} [ <var>flags</var> ... ] ]</dt>
<dd><p>Without any argument print current emulation mode.
</p>
<p>With single argument set up zsh options to emulate the specified shell
as much as possible.
<cite>csh</cite> will never be fully emulated.
If the argument is not one of the shells listed above, <tt>zsh</tt>
will be used as a default; more precisely, the tests performed on the
argument are the same as those used to determine the emulation at startup
based on the shell name, see
<a href="Invocation.html#Compatibility">Compatibility</a>
. In addition to setting shell options, the command also restores
the pristine state of pattern enables, as if all patterns had been
enabled using <tt>enable -p</tt>.
</p>
<p>If the <tt>emulate</tt> command occurs inside a function that has been
marked for execution tracing with <tt>functions -t</tt> then the <tt>xtrace</tt>
option will be turned on regardless of emulation mode or other options.
Note that code executed inside the function by the <tt>.</tt>, <tt>source</tt>, or
<tt>eval</tt> commands is not considered to be running directly from the
function, hence does not provoke this behaviour.
</p>
<p>If the <tt>-R</tt> switch is given, all settable options
are reset to their default value corresponding to the specified emulation
mode, except for certain options describing the interactive
environment; otherwise, only those options likely to cause portability
problems in scripts and functions are altered. If the <tt>-L</tt> switch is given,
the options <tt>LOCAL_OPTIONS</tt>, <tt>LOCAL_PATTERNS</tt> and <tt>LOCAL_TRAPS</tt>
will be set as
well, causing the effects of the <tt>emulate</tt> command and any <tt>setopt</tt>,
<tt>disable -p</tt> or <tt>enable -p</tt>, and <tt>trap</tt> commands to be local to
the immediately surrounding shell
function, if any; normally these options are turned off in all emulation
modes except <tt>ksh</tt>. The <tt>-L</tt> switch is mutually exclusive with the
use of <tt>-c</tt> in <var>flags</var>.
</p>
<p>If there is a single argument and the <tt>-l</tt> switch is given, the
options that would be set or unset (the latter indicated with the prefix
‘<tt>no</tt>’) are listed. <tt>-l</tt> can be combined with <tt>-L</tt> or <tt>-R</tt> and
the list will be modified in the appropriate way. Note the list does
not depend on the current setting of options, i.e. it includes all
options that may in principle change, not just those that would actually
change.
</p>
<p>The <var>flags</var> may be any of the invocation-time flags described in
<a href="Invocation.html#Invocation">Invocation</a>,
except that ‘<tt>-o EMACS</tt>’ and ‘<tt>-o VI</tt>’ may not be used. Flags such
as ‘<tt>+r</tt>’/‘<tt>+o RESTRICTED</tt>’ may be prohibited in some circumstances.
</p>
<p>If <tt>-c</tt> <var>arg</var> appears in <var>flags</var>, <var>arg</var> is evaluated while the
requested emulation is temporarily in effect. In this case the emulation
mode and all options are restored to their previous values before
<tt>emulate</tt> returns. The <tt>-R</tt> switch may precede the name of the shell
to emulate; note this has a meaning distinct from including <tt>-R</tt> in
<var>flags</var>.
</p>
<p>Use of <tt>-c</tt> enables ‘sticky’ emulation mode for functions defined
within the evaluated expression: the emulation mode is associated
thereafter with the function so that whenever the function is executed
the emulation (respecting the <tt>-R</tt> switch, if present) and all
options are set (and pattern disables cleared)
before entry to the function, and the state is restored after exit.
If the function is called when the sticky emulation is already in
effect, either within an ‘<tt>emulate</tt> <var>shell</var> <tt>-c</tt>’ expression or
within another function with the same sticky emulation, entry and exit
from the function do not cause options to be altered (except due to
standard processing such as the <tt>LOCAL_OPTIONS</tt> option). This also
applies to functions marked for autoload within the sticky emulation;
the appropriate set of options will be applied at the point the
function is loaded as well as when it is run.
</p>
<p>For example:
</p>
<div class="example">
<pre class="example">emulate sh -c 'fni() { setopt cshnullglob; }
fno() { fni; }'
fno
</pre></div>
<p>The two functions <tt>fni</tt> and <tt>fno</tt> are defined with sticky <tt>sh</tt>
emulation. <tt>fno</tt> is then executed, causing options associated
with emulations to be set to their values in <tt>sh</tt>. <tt>fno</tt> then
calls <tt>fni</tt>; because <tt>fni</tt> is also marked for sticky <tt>sh</tt>
emulation, no option changes take place on entry to or exit from it.
Hence the option <tt>cshnullglob</tt>, turned off by <tt>sh</tt> emulation, will
be turned on within <tt>fni</tt> and remain on return to <tt>fno</tt>. On exit
from <tt>fno</tt>, the emulation mode and all options will be restored to the
state they were in before entry to the temporary emulation.
</p>
<p>The documentation above is typically sufficient for the intended
purpose of executing code designed for other shells in a suitable
environment. More detailed rules follow.
</p><dl compact="compact">
<dt>1.</dt>
<dd><p>The sticky emulation environment provided by ‘<tt>emulate</tt>
<var>shell</var> <tt>-c</tt>’ is identical to that provided by entry to
a function marked for sticky emulation as a consequence of being
defined in such an environment. Hence, for example, the sticky
emulation is inherited by subfunctions defined within functions
with sticky emulation.
</p></dd>
<dt>2.</dt>
<dd><p>No change of options takes place on entry to or exit from
functions that are not marked for sticky emulation, other than those
that would normally take place, even if those functions are called
within sticky emulation.
</p></dd>
<dt>3.</dt>
<dd><p>No special handling is provided for functions marked for
<tt>autoload</tt> nor for functions present in wordcode created by
the <tt>zcompile</tt> command.
</p></dd>
<dt>4.</dt>
<dd><p>The presence or absence of the <tt>-R</tt> switch to <tt>emulate</tt>
corresponds to different sticky emulation modes, so for example
‘<tt>emulate sh -c</tt>’, ‘<tt>emulate -R sh -c</tt>’ and ‘<tt>emulate csh -c</tt>’
are treated as three distinct sticky emulations.
</p></dd>
<dt>5.</dt>
<dd><p>Difference in shell options supplied in addition to the
basic emulation also mean the sticky emulations are different, so for
example ‘<tt>emulate zsh -c</tt>’ and ‘<tt>emulate zsh -o cbases -c</tt>’ are
treated as distinct sticky emulations.
</p></dd>
</dl>
<a name="index-enable"></a>
<a name="index-enabling-commands"></a>
<a name="index-commands_002c-enabling"></a>
</dd>
<dt><tt>enable</tt> [ <tt>-afmprs</tt> ] <var>name</var> ...</dt>
<dd><p>Enable the <var>name</var>d hash table elements, presumably disabled
earlier with <tt>disable</tt>. The default is to enable builtin commands.
The <tt>-a</tt> option causes <tt>enable</tt> to act on regular or global aliases.
The <tt>-s</tt> option causes <tt>enable</tt> to act on suffix aliases.
The <tt>-f</tt> option causes <tt>enable</tt> to act on shell functions. The <tt>-r</tt>
option causes <tt>enable</tt> to act on reserved words. Without arguments
all enabled hash table elements from the corresponding hash table are
printed. With the <tt>-m</tt> flag the arguments are taken as patterns
(should be quoted) and all hash table elements from the corresponding
hash table matching these patterns are enabled. Enabled objects can be
disabled with the <tt>disable</tt> builtin command.
</p>
<p><tt>enable -p</tt> reenables patterns disabled with <tt>disable -p</tt>. Note
that it does not override globbing options; for example, ‘<tt>enable -p
"~"</tt>’ does not cause the pattern character <tt>~</tt> to be active unless
the <tt>EXTENDED_GLOB</tt> option is also set. To enable all possible
patterns (so that they may be individually disabled with <tt>disable -p</tt>),
use ‘<tt>setopt EXTENDED_GLOB KSH_GLOB NO_SH_GLOB</tt>’.
</p>
<a name="index-eval"></a>
<a name="index-evaluating-arguments-as-commands"></a>
</dd>
<dt><tt>eval</tt> [ <var>arg</var> ... ]</dt>
<dd><p>Read the arguments as input to the shell and execute the resulting
command(s) in the current shell process. The return status is
the same as if the commands had been executed directly by the shell;
if there are no <var>args</var> or they contain no commands (i.e. are
an empty string or whitespace) the return status is zero.
</p>
</dd>
<dt><tt>exec</tt> [ <tt>-cl</tt> ] [ <tt>-a</tt> <var>argv0</var> ] [ <var>command</var> [ <var>arg</var> ... ] ]</dt>
<dd><p>Replace the current shell with <var>command</var> rather than forking.
If <var>command</var> is a shell builtin command or a shell function,
the shell executes it, and exits when the command is complete.
</p>
<p>With <tt>-c</tt> clear the environment; with <tt>-l</tt> prepend <tt>-</tt> to the
<tt>argv[0]</tt> string of the command executed (to simulate a login shell);
with <tt>-a</tt> <var>argv0</var> set the <tt>argv[0]</tt> string of the command
executed.
See <a href="Shell-Grammar.html#Precommand-Modifiers">Precommand Modifiers</a>.
</p>
<p>If the option <tt>POSIX_BUILTINS</tt> is set, <var>command</var> is never
interpreted as a shell builtin command or shell function. This
means further precommand modifiers such as <tt>builtin</tt> and
<tt>noglob</tt> are also not interpreted within the shell. Hence
<var>command</var> is always found by searching the command path.
</p>
<a name="index-redirection_002c-current-shell_0027s-I_002fO"></a>
<p>If <var>command</var> is omitted but any redirections are specified,
then the redirections will take effect in the current shell.
</p>
<a name="index-exit"></a>
</dd>
<dt><tt>exit</tt> [ <var>n</var> ]</dt>
<dd><p>Exit the shell with the exit status specified by an arithmetic
expression <var>n</var>; if none
is specified, use the exit status from the last command executed.
<a name="index-IGNORE_005fEOF_002c-use-of"></a>
An EOF condition will also cause the shell to exit, unless
the <tt>IGNORE_EOF</tt> option is set.
</p>
<p>See notes at the end of
<a href="Jobs-_0026-Signals.html#Jobs-_0026-Signals">Jobs & Signals</a> for some possibly unexpected interactions
of the <tt>exit</tt> command with jobs.
</p>
<a name="index-export-1"></a>
</dd>
<dt><tt>export</tt> [ <var>name</var>[<tt>=</tt><var>value</var>] ... ]</dt>
<dd><p>The specified <var>name</var>s are marked for automatic export
to the environment of subsequently executed commands.
Equivalent to <tt>typeset -gx</tt>.
If a parameter specified does not
already exist, it is created in the global scope.
</p>
<a name="index-false"></a>
<a name="index-doing-nothing_002c-unsuccessfully"></a>
</dd>
<dt><tt>false</tt> [ <var>arg</var> ... ]</dt>
<dd><p>Do nothing and return an exit status of 1.
</p>
<a name="index-fc"></a>
<a name="index-history_002c-editing"></a>
<a name="index-editing-history"></a>
</dd>
<dt><tt>fc</tt> [ <tt>-e</tt> <var>ename</var> ] [ <tt>-LI</tt> ] [ <tt>-m</tt> <var>match</var> ] [ <var>old</var><tt>=</tt><var>new</var> ... ] [ <var>first</var> [ <var>last</var> ] ]</dt>
<dt><tt>fc -l </tt>[ <tt>-LI</tt> ] [ <tt>-nrdfEiD</tt> ] [ <tt>-t</tt> <var>timefmt</var> ] [ <tt>-m</tt> <var>match</var> ]</dt>
<dt><tt> </tt>[ <var>old</var><tt>=</tt><var>new</var> ... ] [ <var>first</var> [ <var>last</var> ] ]</dt>
<dt><tt>fc -p </tt>[ <tt>-a</tt> ] [ <var>filename</var> [ <var>histsize</var> [ <var>savehistsize</var> ] ] ]</dt>
<dt><tt>fc</tt> <tt>-P</tt></dt>
<dt><tt>fc</tt> <tt>-ARWI</tt> [ <var>filename</var> ]</dt>
<dd><p>The <tt>fc</tt> command controls the interactive history mechanism. Note
that reading and writing of history options is only performed if the
shell is interactive. Usually this is detected automatically, but
it can be forced by setting the <tt>interactive</tt> option when starting the
shell.
</p>
<p>The first two forms of this command select a range of events from
<var>first</var> to <var>last</var> from the history list. The arguments <var>first</var>
and <var>last</var> may be specified as a number or as a string. A negative
number is used as an offset to the current history event number. A string
specifies the most recent event beginning with the given string. All
substitutions <var>old</var><tt>=</tt><var>new</var>, if any, are then performed on the
text of the events.
</p>
<p>In addition to the number range,
</p><dl compact="compact">
<dt><tt>-I</tt></dt>
<dd><p>restricts to only internal events (not from <tt>$HISTFILE</tt>)
</p></dd>
<dt><tt>-L</tt></dt>
<dd><p>restricts to only local events (not from other shells, see
<tt>SHARE_HISTORY</tt> in <a href="Options.html#Description-of-Options">Description of Options</a> – note that <tt>$HISTFILE</tt> is
considered local when read at startup)
</p></dd>
<dt><tt>-m</tt></dt>
<dd><p>takes the first argument as a pattern (should be quoted) and
only the history events matching this pattern are considered
</p></dd>
</dl>
<p>If <var>first</var> is not specified, it will be set to -1 (the most recent
event), or to -16 if the <tt>-l</tt> flag is given.
If <var>last</var> is not specified, it will be set to <var>first</var>,
or to -1 if the <tt>-l</tt> flag is given.
However, if the current event has added entries to the history with
‘<tt>print -s</tt>’ or ‘<tt>fc -R</tt>’, then the default <var>last</var> for <tt>-l</tt>
includes all new history entries since the current event began.
</p>
<p>When the <tt>-l</tt> flag is given, the resulting events are listed on
standard output. Otherwise the editor program <var>ename</var> is invoked on a
file containing these history events. If <var>ename</var> is not given, the
value of the parameter <tt>FCEDIT</tt> is used; if that is not set the value of
the parameter <tt>EDITOR</tt> is used; if that is not set a builtin default,
usually ‘<tt>vi</tt>’ is used. If <var>ename</var> is ‘<tt>-</tt>’, no editor is invoked.
When editing is complete, the edited command is executed.
</p>
<p>The flag <tt>-r</tt> reverses the order of the events and the
flag <tt>-n</tt> suppresses event numbers when listing.
</p>
<p>Also when listing,
</p><dl compact="compact">
<dt><tt>-d</tt></dt>
<dd><p>prints timestamps for each event
</p></dd>
<dt><tt>-f</tt></dt>
<dd><p>prints full time-date stamps in the US
‘<var>MM</var><tt>/</tt><var>DD</var><tt>/</tt><var>YY</var> <var>hh</var><tt>:</tt><var>mm</var>’ format
</p></dd>
<dt><tt>-E</tt></dt>
<dd><p>prints full time-date stamps in the European
‘<var>dd</var><tt>.</tt><var>mm</var><tt>.</tt><var>yyyy</var> <var>hh</var><tt>:</tt><var>mm</var>’ format
</p></dd>
<dt><tt>-i</tt></dt>
<dd><p>prints full time-date stamps in ISO8601
‘<var>yyyy</var><tt>-</tt><var>mm</var><tt>-</tt><var>dd</var> <var>hh</var><tt>:</tt><var>mm</var>’ format
</p></dd>
<dt><tt>-t</tt> <var>fmt</var></dt>
<dd><p>prints time and date stamps in the given format;
<var>fmt</var> is formatted with the strftime function with the zsh extensions
described for the <tt>%D{</tt><var>string</var><tt>}</tt> prompt format in
<a href="Prompt-Expansion.html#Prompt-Expansion">Prompt Expansion</a>. The resulting formatted string must be
no more than 256 characters or will not be printed
</p>
</dd>
<dt><tt>-D</tt></dt>
<dd><p>prints elapsed times; may be combined with one of the
options above
</p></dd>
</dl>
<a name="index-history_002c-stack"></a>
<a name="index-stack_002c-history"></a>
<p>‘<tt>fc -p</tt>’ pushes the current history list onto a stack and switches to a
new history list. If the <tt>-a</tt> option is also specified, this history list
will be automatically popped when the current function scope is exited, which
is a much better solution than creating a trap function to call ‘<tt>fc -P</tt>’
manually. If no arguments are specified, the history list is left empty,
<tt>$HISTFILE</tt> is unset, and <tt>$HISTSIZE</tt> & <tt>$SAVEHIST</tt> are set to their
default values. If one argument is given, <tt>$HISTFILE</tt> is set to that
filename, <tt>$HISTSIZE</tt> & <tt>$SAVEHIST</tt> are left unchanged, and the history
file is read in (if it exists) to initialize the new list. If a second
argument is specified, <tt>$HISTSIZE</tt> & <tt>$SAVEHIST</tt> are instead set to the
single specified numeric value. Finally, if a third argument is specified,
<tt>$SAVEHIST</tt> is set to a separate value from <tt>$HISTSIZE</tt>. You are free to
change these environment values for the new history list however you desire
in order to manipulate the new history list.
</p>
<p>‘<tt>fc -P</tt>’ pops the history list back to an older list saved by ‘<tt>fc -p</tt>’.
The current list is saved to its <tt>$HISTFILE</tt> before it is destroyed
(assuming that <tt>$HISTFILE</tt> and <tt>$SAVEHIST</tt> are set appropriately, of
course). The values of <tt>$HISTFILE</tt>, <tt>$HISTSIZE</tt>, and <tt>$SAVEHIST</tt> are
restored to the values they had when ‘<tt>fc -p</tt>’ was called. Note that this
restoration can conflict with making these variables "local", so your best
bet is to avoid local declarations for these variables in functions that use
‘<tt>fc -p</tt>’. The one other guaranteed-safe combination is declaring these
variables to be local at the top of your function and using the automatic
option (<tt>-a</tt>) with ‘<tt>fc -p</tt>’. Finally, note that it is legal to manually
pop a push marked for automatic popping if you need to do so before the
function exits.
</p>
<a name="index-history_002c-file"></a>
<a name="index-file_002c-history"></a>
<p>‘<tt>fc -R</tt>’ reads the history from the given file,
‘<tt>fc -W</tt>’ writes the history out to the given file,
and ‘<tt>fc -A</tt>’ appends the history out to the given file.
If no filename is specified, the <tt>$HISTFILE</tt> is assumed.
If the <tt>-I</tt> option is added to <tt>-R</tt>, only those events that are
not already contained within the internal history list are added.
If the <tt>-I</tt> option is added to <tt>-A</tt> or <tt>-W</tt>, only those
events that are new since last incremental append/write to
the history file are appended/written.
In any case, the created file will have no more than <tt>$SAVEHIST</tt>
entries.
</p>
<a name="index-fg"></a>
<a name="index-jobs_002c-foregrounding"></a>
<a name="index-jobs_002c-resuming"></a>
</dd>
<dt><tt>fg</tt> [ <var>job</var> ... ]</dt>
<dt><var>job</var> ...</dt>
<dd><p>Bring each specified <var>job</var> in turn to the foreground.
If no <var>job</var> is specified, resume the current job.
</p>
<a name="index-float"></a>
</dd>
<dt><tt>float</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>Hghlprtux</tt> ] [ {<tt>+</tt>|<tt>-</tt>}<tt>EFLRZ</tt> [ <var>n</var> ] ] [ <var>name</var>[<tt>=</tt><var>value</var>] ... ]</dt>
<dd><p>Equivalent to <tt>typeset -E</tt>, except that options irrelevant to floating
point numbers are not permitted.
</p>
<a name="index-functions-1"></a>
</dd>
<dt><tt>functions</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>UkmtTuWz</tt> ] [ <tt>-x</tt> <var>num</var> ] [ <var>name</var> ... ]</dt>
<dt><tt>functions -M</tt> [<tt>-s</tt>] <var>mathfn</var> [ <var>min</var> [ <var>max</var> [ <var>shellfn</var> ] ] ]</dt>
<dt><tt>functions -M</tt> [ <tt>-m</tt> <var>pattern</var> ... ]</dt>
<dt><tt>functions +M</tt> [ <tt>-m</tt> ] <var>mathfn</var> ...</dt>
<dd><p>Equivalent to <tt>typeset -f</tt>, with the exception of the <tt>-x</tt>,
<tt>-M</tt> and <tt>-W</tt> options. For <tt>functions -u</tt> and <tt>functions -U</tt>,
see <tt>autoload</tt>, which provides additional options.
</p>
<p>The <tt>-x</tt> option indicates that any functions output will have
each leading tab for indentation, added by the shell to show syntactic
structure, expanded to the given number <var>num</var> of spaces. <var>num</var>
can also be 0 to suppress all indentation.
</p>
<p>The <tt>-W</tt> option turns on the option <tt>WARN_NESTED_VAR</tt> for the named
function or functions only. The option is turned off at the start of
nested functions (apart from anonoymous functions) unless the called
function also has the <tt>-W</tt> attribute.
</p>
<p>Use of the <tt>-M</tt> option may not be combined with any of the options
handled by <tt>typeset -f</tt>.
</p>
<p><tt>functions -M</tt> <var>mathfn</var> defines <var>mathfn</var> as the name of
a mathematical function recognised in all forms of arithmetical expressions;
see
<a href="Arithmetic-Evaluation.html#Arithmetic-Evaluation">Arithmetic Evaluation</a>. By default <var>mathfn</var> may take
any number of comma-separated arguments. If <var>min</var> is given,
it must have exactly <var>min</var> args; if <var>min</var> and <var>max</var> are
both given, it must have at least <var>min</var> and at most <var>max</var>
args. <var>max</var> may be -1 to indicate that there is no upper limit.
</p>
<p>By default the function is implemented by a shell function of the same
name; if <var>shellfn</var> is specified it gives the name of the corresponding
shell function while <var>mathfn</var> remains the name used in arithmetical
expressions. The name of the function in <tt>$0</tt> is <var>mathfn</var> (not
<var>shellfn</var> as would usually be the case), provided the option
<tt>FUNCTION_ARGZERO</tt> is in effect. The positional parameters in the shell
function correspond to the arguments of the mathematical function call.
The result of the last arithmetical expression evaluated
inside the shell function (even if it is a form that normally only returns
a status) gives the result of the mathematical function.
</p>
<p>If the additional option <tt>-s</tt> is given to <tt>functions -M</tt>, the
argument to the function is a single string: anything between the
opening and matching closing parenthesis is passed to the function as a
single argument, even if it includes commas or white space. The minimum
and maximum argument specifiers must therefore be 1 if given. An empty
argument list is passed as a zero-length string.
</p>
<p><tt>functions -M</tt> with no arguments lists all such user-defined functions in
the same form as a definition. With the additional option <tt>-m</tt> and
a list of arguments, all functions whose <var>mathfn</var> matches one of
the pattern arguments are listed.
</p>
<p><tt>function +M</tt> removes the list of mathematical functions; with the
additional option <tt>-m</tt> the arguments are treated as patterns and
all functions whose <var>mathfn</var> matches the pattern are removed. Note
that the shell function implementing the behaviour is not removed
(regardless of whether its name coincides with <var>mathfn</var>).
</p>
<p>For example, the following prints the cube of 3:
</p>
<div class="example">
<pre class="example">zmath_cube() { (( $1 * $1 * $1 )) }
functions -M cube 1 1 zmath_cube
print $(( cube(3) ))
</pre></div>
<p>The following string function takes a single argument, including
the commas, so prints 11:
</p>
<div class="example">
<pre class="example">stringfn() { (( $#1 )) }
functions -Ms stringfn
print $(( stringfn(foo,bar,rod) ))
</pre></div>
</dd>
<dt><tt>getcap</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcap-Module">The zsh/cap Module</a>.
</p>
<a name="index-getln"></a>
<a name="index-line_002c-reading"></a>
<a name="index-reading-a-line"></a>
</dd>
<dt><tt>getln</tt> [ <tt>-AclneE</tt> ] <var>name</var> ...</dt>
<dd><p>Read the top value from the buffer stack and put it in
the shell parameter <var>name</var>. Equivalent to
<tt>read -zr</tt>.
</p>
<a name="index-getopts"></a>
<a name="index-options_002c-processing"></a>
</dd>
<dt><tt>getopts</tt> <var>optstring</var> <var>name</var> [ <var>arg</var> ... ]</dt>
<dd><p>Checks the <var>arg</var>s for legal options. If the <var>arg</var>s are omitted,
use the positional parameters. A valid option argument
begins with a ‘<tt>+</tt>’ or a ‘<tt>-</tt>’. An argument not beginning with
a ‘<tt>+</tt>’ or a ‘<tt>-</tt>’, or the argument ‘<tt>-</tt><tt>-</tt>’, ends the options.
Note that a single ‘<tt>-</tt>’ is not considered a valid option argument.
<var>optstring</var> contains the letters that <tt>getopts</tt>
recognizes. If a letter is followed by a ‘<tt>:</tt>’, that option
requires an argument. The options can be
separated from the argument by blanks.
</p>
<p>Each time it is invoked, <tt>getopts</tt> places the option letter it finds
in the shell parameter <var>name</var>, prepended with a ‘<tt>+</tt>’ when
<var>arg</var> begins with a ‘<tt>+</tt>’. The index of the next <var>arg</var>
is stored in <tt>OPTIND</tt>. The option argument, if any,
is stored in <tt>OPTARG</tt>.
<a name="index-OPTIND_002c-use-of"></a>
<a name="index-OPTARG_002c-use-of"></a>
</p>
<p>The first option to be examined may be changed by explicitly assigning
to <tt>OPTIND</tt>. <tt>OPTIND</tt> has an initial value of <tt>1</tt>, and is
normally set to <tt>1</tt> upon entry to a shell function and restored
upon exit (this is disabled by the <tt>POSIX_BUILTINS</tt> option). <tt>OPTARG</tt>
is not reset and retains its value from the most recent call to
<tt>getopts</tt>. If either of <tt>OPTIND</tt> or <tt>OPTARG</tt> is explicitly
unset, it remains unset, and the index or option argument is not
stored. The option itself is still stored in <var>name</var> in this case.
</p>
<p>A leading ‘<tt>:</tt>’ in <var>optstring</var> causes <tt>getopts</tt> to store the
letter of any invalid option in <tt>OPTARG</tt>, and to set <var>name</var> to
‘<tt>?</tt>’ for an unknown option and to ‘<tt>:</tt>’ when a required argument is
missing. Otherwise, <tt>getopts</tt> sets <var>name</var> to ‘<tt>?</tt>’ and prints
an error message when an option is invalid. The exit status is
nonzero when there are no more options.
</p>
<a name="index-hash-1"></a>
</dd>
<dt><tt>hash</tt> [ <tt>-Ldfmrv</tt> ] [ <var>name</var>[<tt>=</tt><var>value</var>] ] ...</dt>
<dd><p><tt>hash</tt> can be used to directly modify the contents of the command
hash table, and the named directory hash table. Normally one would
modify these tables by modifying one’s <tt>PATH</tt>
(for the command hash table) or by creating appropriate shell parameters
(for the named directory hash table).
The choice of hash table to work on is determined by the <tt>-d</tt> option;
without the option the command hash table is used, and with the option the
named directory hash table is used.
</p>
<p>Given no arguments, and neither the <tt>-r</tt> or <tt>-f</tt> options,
the selected hash table will be listed in full.
</p>
<p>The <tt>-r</tt> option causes the selected hash table to be emptied.
It will be subsequently rebuilt in the normal fashion.
The <tt>-f</tt> option causes the selected hash table to be fully
rebuilt immediately. For the command hash table this hashes
all the absolute directories in the <tt>PATH</tt>,
and for the named directory hash table this adds all users’ home directories.
These two options cannot be used with any arguments.
</p>
<p>The <tt>-m</tt> option causes the arguments to be taken as patterns
(which should be quoted) and the elements of the hash table
matching those patterns are printed. This is the only way to display
a limited selection of hash table elements.
</p>
<p>For each <var>name</var> with a corresponding <var>value</var>, put ‘<var>name</var>’ in
the selected hash table, associating it with the pathname ‘<var>value</var>’.
In the command hash table, this means that
whenever ‘<var>name</var>’ is used as a command argument, the shell will try
to execute the file given by ‘<var>value</var>’.
In the named directory hash table, this means
that ‘<var>value</var>’ may be referred to as ‘<tt>~</tt><var>name</var>’.
</p>
<p>For each <var>name</var> with no
corresponding <var>value</var>, attempt to add <var>name</var> to the hash table,
checking what the appropriate <tt>value</tt> is in the normal manner for
that hash table. If an appropriate <tt>value</tt> can’t be found, then
the hash table will be unchanged.
</p>
<p>The <tt>-v</tt> option causes hash table entries to be listed as they are
added by explicit specification. If has no effect if used with <tt>-f</tt>.
</p>
<p>If the <tt>-L</tt> flag is present, then each hash table entry is printed in
the form of a call to hash.
</p>
<a name="index-history-1"></a>
</dd>
<dt><tt>history</tt></dt>
<dd><p>Same as <tt>fc -l</tt>.
</p>
<a name="index-integer"></a>
</dd>
<dt><tt>integer</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>Hghlprtux</tt> ] [ {<tt>+</tt>|<tt>-</tt>}<tt>LRZi</tt> [ <var>n</var> ] ] [ <var>name</var>[<tt>=</tt><var>value</var>] ... ]</dt>
<dd><p>Equivalent to <tt>typeset -i</tt>, except that options irrelevant to
integers are not permitted.
</p>
<a name="index-jobs-1"></a>
</dd>
<dt><tt>jobs</tt> [ <tt>-dlprs</tt> ] [ <var>job</var> ... ]</dt>
<dt><tt>jobs -Z</tt> <var>string</var></dt>
<dd><p>Lists information about each given job, or all jobs
if <var>job</var> is omitted. The <tt>-l</tt> flag lists process
IDs, and the <tt>-p</tt> flag lists process groups.
If the <tt>-r</tt> flag is specified only running jobs will be listed
and if the <tt>-s</tt> flag is given only stopped jobs are shown.
If the <tt>-d</tt> flag is given, the directory from which the job was
started (which may not be the current directory of the job) will also
be shown.
</p>
<p>The <tt>-Z</tt> option replaces the shell’s argument and environment space with
the given string, truncated if necessary to fit. This will normally be
visible in <tt>ps</tt> (man page ps(1)) listings. This feature is typically
used by daemons, to indicate their state.
</p>
<a name="index-kill"></a>
<a name="index-killing-jobs"></a>
<a name="index-jobs_002c-killing"></a>
</dd>
<dt><tt>kill</tt> [ <tt>-s</tt> <var>signal_name</var> | <tt>-n</tt> <var>signal_number</var> | <tt>-</tt><var>sig</var> ] <var>job</var> ...</dt>
<dt><tt>kill</tt> <tt>-l</tt> [ <var>sig</var> ... ]</dt>
<dd><p>Sends either <tt>SIGTERM</tt> or the specified signal to the given
jobs or processes.
Signals are given by number or by names, with or without the ‘<tt>SIG</tt>’
prefix.
If the signal being sent is not ‘<tt>KILL</tt>’ or ‘<tt>CONT</tt>’, then the job
will be sent a ‘<tt>CONT</tt>’ signal if it is stopped.
The argument <var>job</var> can be the process ID of a job
not in the job list.
In the second form, <tt>kill -l</tt>, if <var>sig</var> is not
specified the signal names are listed. Otherwise, for each
<var>sig</var> that is a name, the corresponding signal number is
listed. For each <var>sig</var> that is a signal number or a number
representing the exit status of a process which was terminated or
stopped by a signal the name of the signal is printed.
</p>
<p>On some systems, alternative signal names are allowed for a few signals.
Typical examples are <tt>SIGCHLD</tt> and <tt>SIGCLD</tt> or <tt>SIGPOLL</tt> and
<tt>SIGIO</tt>, assuming they correspond to the same signal number. <tt>kill
-l</tt> will only list the preferred form, however <tt>kill -l</tt> <var>alt</var> will
show if the alternative form corresponds to a signal number. For example,
under Linux <tt>kill -l IO</tt> and <tt>kill -l POLL</tt> both output 29, hence
<tt>kill -IO</tt> and <tt>kill -POLL</tt> have the same effect.
</p>
<p>Many systems will allow process IDs to be negative to kill a process
group or zero to kill the current process group.
</p>
<a name="index-let"></a>
</dd>
<dt><tt>let</tt> <var>arg</var> ...</dt>
<dd><p>Evaluate each <var>arg</var> as an arithmetic expression.
See
<a href="Arithmetic-Evaluation.html#Arithmetic-Evaluation">Arithmetic Evaluation</a>
for a description of arithmetic expressions. The exit status is 0 if the
value of the last expression is nonzero, 1 if it is zero, and 2 if
an error occurred.
</p>
<a name="index-limit"></a>
<a name="index-resource-limits"></a>
<a name="index-limits_002c-resource"></a>
</dd>
<dt><tt>limit</tt> [ <tt>-hs</tt> ] [ <var>resource</var> [ <var>limit</var> ] ] ...</dt>
<dd><p>Set or display resource limits. Unless the <tt>-s</tt> flag is given,
the limit applies only the children of the shell. If <tt>-s</tt> is
given without other arguments, the resource limits of the current
shell is set to the previously set resource limits of the children.
</p>
<p>If <var>limit</var> is not specified, print the current limit placed
on <var>resource</var>, otherwise
set the limit to the specified value. If the <tt>-h</tt> flag
is given, use hard limits instead of soft limits.
If no <var>resource</var> is given, print all limits.
</p>
<p>When looping over multiple resources, the shell will abort immediately if
it detects a badly formed argument. However, if it fails to set a limit
for some other reason it will continue trying to set the remaining limits.
</p>
<p><var>resource</var> can be one of:
</p>
<dl compact="compact">
<dt><tt>addressspace</tt></dt>
<dd><p>Maximum amount of address space used.
</p></dd>
<dt><tt>aiomemorylocked</tt></dt>
<dd><p>Maximum amount of memory locked in RAM for AIO operations.
</p></dd>
<dt><tt>aiooperations</tt></dt>
<dd><p>Maximum number of AIO operations.
</p></dd>
<dt><tt>cachedthreads</tt></dt>
<dd><p>Maximum number of cached threads.
</p></dd>
<dt><tt>coredumpsize</tt></dt>
<dd><p>Maximum size of a core dump.
</p></dd>
<dt><tt>cputime</tt></dt>
<dd><p>Maximum CPU seconds per process.
</p></dd>
<dt><tt>datasize</tt></dt>
<dd><p>Maximum data size (including stack) for each process.
</p></dd>
<dt><tt>descriptors</tt></dt>
<dd><p>Maximum value for a file descriptor.
</p></dd>
<dt><tt>filesize</tt></dt>
<dd><p>Largest single file allowed.
</p></dd>
<dt><tt>kqueues</tt></dt>
<dd><p>Maximum number of kqueues allocated.
</p></dd>
<dt><tt>maxproc</tt></dt>
<dd><p>Maximum number of processes.
</p></dd>
<dt><tt>maxpthreads</tt></dt>
<dd><p>Maximum number of threads per process.
</p></dd>
<dt><tt>memorylocked</tt></dt>
<dd><p>Maximum amount of memory locked in RAM.
</p></dd>
<dt><tt>memoryuse</tt></dt>
<dd><p>Maximum resident set size.
</p></dd>
<dt><tt>msgqueue</tt></dt>
<dd><p>Maximum number of bytes in POSIX message queues.
</p></dd>
<dt><tt>posixlocks</tt></dt>
<dd><p>Maximum number of POSIX locks per user.
</p></dd>
<dt><tt>pseudoterminals</tt></dt>
<dd><p>Maximum number of pseudo-terminals.
</p></dd>
<dt><tt>resident</tt></dt>
<dd><p>Maximum resident set size.
</p></dd>
<dt><tt>sigpending</tt></dt>
<dd><p>Maximum number of pending signals.
</p></dd>
<dt><tt>sockbufsize</tt></dt>
<dd><p>Maximum size of all socket buffers.
</p></dd>
<dt><tt>stacksize</tt></dt>
<dd><p>Maximum stack size for each process.
</p></dd>
<dt><tt>swapsize</tt></dt>
<dd><p>Maximum amount of swap used.
</p></dd>
<dt><tt>vmemorysize</tt></dt>
<dd><p>Maximum amount of virtual memory.
</p></dd>
</dl>
<p>Which of these resource limits are available depends on the system.
<var>resource</var> can be abbreviated to any unambiguous prefix. It
can also be an integer, which corresponds to the integer defined
for the resource by the operating system.
</p>
<p>If argument corresponds to a number which is out of the range of the
resources configured into the shell, the shell will try to read or write
the limit anyway, and will report an error if this fails. As the shell
does not store such resources internally, an attempt to set the limit will
fail unless the <tt>-s</tt> option is present.
</p>
<p><var>limit</var> is a number, with an optional scaling factor, as follows:
</p>
<dl compact="compact">
<dt><var>n</var><tt>h</tt></dt>
<dd><p>hours
</p></dd>
<dt><var>n</var><tt>k</tt></dt>
<dd><p>kilobytes (default)
</p></dd>
<dt><var>n</var><tt>m</tt></dt>
<dd><p>megabytes or minutes
</p></dd>
<dt><var>n</var><tt>g</tt></dt>
<dd><p>gigabytes
</p></dd>
<dt>[<var>mm</var><tt>:</tt>]<var>ss</var></dt>
<dd><p>minutes and seconds
</p></dd>
</dl>
<p>The <tt>limit</tt> command is not made available by default when the
shell starts in a mode emulating another shell. It can be made available
with the command ‘<tt>zmodload -F zsh/rlimits b:limit</tt>’.
</p>
<a name="index-local"></a>
</dd>
<dt><tt>local</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>AHUahlprtux</tt> ] [ {<tt>+</tt>|<tt>-</tt>}<tt>EFLRZi</tt> [ <var>n</var> ] ] [ <var>name</var>[<tt>=</tt><var>value</var>] ... ]</dt>
<dd><p>Same as <tt>typeset</tt>, except that the options <tt>-g</tt>, and
<tt>-f</tt> are not permitted. In this case the <tt>-x</tt> option does not force
the use of <tt>-g</tt>, i.e. exported variables will be local to functions.
</p>
<a name="index-log"></a>
<a name="index-watch_002c-use-of"></a>
<a name="index-watching-users"></a>
<a name="index-users_002c-watching"></a>
</dd>
<dt><tt>log</tt></dt>
<dd><p>List all users currently logged in who are affected by
the current setting of the <tt>watch</tt> parameter.
</p>
<a name="index-logout"></a>
</dd>
<dt><tt>logout</tt> [ <var>n</var> ]</dt>
<dd><p>Same as <tt>exit</tt>, except that it only works in a login shell.
</p>
</dd>
<dt><tt>noglob</tt> <var>simple command</var></dt>
<dd><p>See <a href="Shell-Grammar.html#Precommand-Modifiers">Precommand Modifiers</a>.
</p>
<a name="index-popd"></a>
</dd>
<dt><tt>popd</tt> [ <tt>-q</tt> ] [ {<tt>+</tt>|<tt>-</tt>}<var>n</var> ]</dt>
<dd><p>Remove an entry from the directory stack, and perform a <tt>cd</tt> to
the new top directory. With no argument, the current top entry is
removed. An argument of the form ‘<tt>+</tt><var>n</var>’ identifies a stack
entry by counting from the left of the list shown by the <tt>dirs</tt> command,
starting with zero. An argument of the form <tt>-</tt><var>n</var> counts from the right.
<a name="index-PUSHD_005fMINUS_002c-use-of-1"></a>
If the <tt>PUSHD_MINUS</tt> option is set, the meanings of ‘<tt>+</tt>’ and
‘<tt>-</tt>’ in this context are swapped.
</p>
<p>If the <tt>-q</tt> (quiet) option is specified, the hook function <tt>chpwd</tt>
and the functions in the array <tt>$chpwd_functions</tt> are not called,
and the new directory stack is not printed. This is useful for calls to
<tt>popd</tt> that do not change the environment seen by an interactive user.
</p>
<a name="index-print"></a>
</dd>
<dt><tt>print </tt>[ <tt>-abcDilmnNoOpPrsSz</tt> ] [ <tt>-u</tt> <var>n</var> ] [ <tt>-f</tt> <var>format</var> ] [ <tt>-C</tt> <var>cols</var> ]</dt>
<dt><tt> </tt>[ <tt>-v</tt> <var>name</var> ] [ <tt>-xX</tt> <var>tabstop</var> ] [ <tt>-R</tt> [ <tt>-en</tt> ]] [ <var>arg</var> ... ]</dt>
<dd><p>With the ‘<tt>-f</tt>’ option the arguments are printed as described by <tt>printf</tt>.
With no flags or with the flag ‘<tt>-</tt>’, the arguments are printed on
the standard output as described by <tt>echo</tt>, with the following differences:
the escape sequence ‘<tt>\M-</tt><var>x</var>’ (or ‘<tt>\M</tt><var>x</var>’) metafies the character
<var>x</var> (sets the highest bit),
‘<tt>\C-</tt><var>x</var>’ (or ‘<tt>\C</tt><var>x</var>’) produces a control character
(‘<tt>\C-@</tt>’ and ‘<tt>\C-?</tt>’ give the characters NULL and delete),
a character code in octal is represented by ‘<tt>\</tt><var>NNN</var>’
(instead of ‘<tt>\0</tt><var>NNN</var>’),
and ‘<tt>\E</tt>’ is a synonym for ‘<tt>\e</tt>’.
Finally, if not in an escape
sequence, ‘<tt>\</tt>’ escapes the following character and is not printed.
</p>
<dl compact="compact">
<dt><tt>-a</tt></dt>
<dd><p>Print arguments with the column incrementing first. Only useful with the
<tt>-c</tt> and <tt>-C</tt> options.
</p>
</dd>
<dt><tt>-b</tt></dt>
<dd><p>Recognize all the escape sequences defined for the <tt>bindkey</tt> command,
see
<a href="Zsh-Line-Editor.html#Zle-Builtins">Zle Builtins</a>.
</p>
</dd>
<dt><tt>-c</tt></dt>
<dd><p>Print the arguments in columns. Unless <tt>-a</tt> is also given, arguments are
printed with the row incrementing first.
</p>
</dd>
<dt><tt>-C</tt> <var>cols</var></dt>
<dd><p>Print the arguments in <var>cols</var> columns. Unless <tt>-a</tt> is also given,
arguments are printed with the row incrementing first.
</p>
</dd>
<dt><tt>-D</tt></dt>
<dd><p>Treat the arguments as paths, replacing directory prefixes with <tt>~</tt>
expressions corresponding to directory names, as appropriate.
</p>
</dd>
<dt><tt>-i</tt></dt>
<dd><p>If given together with <tt>-o</tt> or <tt>-O</tt>, sorting is performed
case-independently.
</p>
</dd>
<dt><tt>-l</tt></dt>
<dd><p>Print the arguments separated by newlines instead of spaces.
</p>
</dd>
<dt><tt>-m</tt></dt>
<dd><p>Take the first argument as a pattern (should be quoted), and remove
it from the argument list together with subsequent arguments that
do not match this pattern.
</p>
</dd>
<dt><tt>-n</tt></dt>
<dd><p>Do not add a newline to the output.
</p>
</dd>
<dt><tt>-N</tt></dt>
<dd><p>Print the arguments separated and terminated by nulls.
</p>
</dd>
<dt><tt>-o</tt></dt>
<dd><p>Print the arguments sorted in ascending order.
</p>
</dd>
<dt><tt>-O</tt></dt>
<dd><p>Print the arguments sorted in descending order.
</p>
</dd>
<dt><tt>-p</tt></dt>
<dd><p>Print the arguments to the input of the coprocess.
</p>
</dd>
<dt><tt>-P</tt></dt>
<dd><p>Perform prompt expansion (see
<a href="Prompt-Expansion.html#Prompt-Expansion">Prompt Expansion</a>).
In combination with ‘<tt>-f</tt>’,
prompt escape sequences are parsed only within interpolated arguments,
not within the format string.
</p>
</dd>
<dt><tt>-r</tt></dt>
<dd><p>Ignore the escape conventions of <tt>echo</tt>.
</p>
</dd>
<dt><tt>-R</tt></dt>
<dd><p>Emulate the BSD <tt>echo</tt> command, which does not process escape sequences
unless the <tt>-e</tt> flag is given. The <tt>-n</tt> flag suppresses the trailing
newline. Only the <tt>-e</tt> and <tt>-n</tt> flags are recognized after
<tt>-R</tt>; all other arguments and options are printed.
</p>
</dd>
<dt><tt>-s</tt></dt>
<dd><p>Place the results in the history list instead of on the standard output.
Each argument to the <tt>print</tt> command is treated as a single word in the
history, regardless of its content.
</p>
</dd>
<dt><tt>-S</tt></dt>
<dd><p>Place the results in the history list instead of on the standard output.
In this case only a single argument is allowed; it will be split into
words as if it were a full shell command line. The effect is
similar to reading the line from a history file with the
<tt>HIST_LEX_WORDS</tt> option active.
</p>
</dd>
<dt><tt>-u</tt> <var>n</var></dt>
<dd><p>Print the arguments to file descriptor <var>n</var>.
</p>
</dd>
<dt><tt>-v</tt> <var>name</var></dt>
<dd><p>Store the printed arguments as the value of the parameter <var>name</var>.
</p>
</dd>
<dt><tt>-x</tt> <var>tab-stop</var></dt>
<dd><p>Expand leading tabs on each line of output in the printed string
assuming a tab stop every <var>tab-stop</var> characters. This is appropriate
for formatting code that may be indented with tabs. Note that leading
tabs of any argument to print, not just the first, are expanded, even if
<tt>print</tt> is using spaces to separate arguments (the column count
is maintained across arguments but may be incorrect on output
owing to previous unexpanded tabs).
</p>
<p>The start of the output of each print command is assumed to be aligned
with a tab stop. Widths of multibyte characters are handled if the
option <tt>MULTIBYTE</tt> is in effect. This option is ignored if other
formatting options are in effect, namely column alignment or
<tt>printf</tt> style, or if output is to a special location such as shell
history or the command line editor.
</p>
</dd>
<dt><tt>-X</tt> <var>tab-stop</var></dt>
<dd><p>This is similar to <tt>-x</tt>, except that all tabs in the printed string
are expanded. This is appropriate if tabs in the arguments are
being used to produce a table format.
</p>
</dd>
<dt><tt>-z</tt></dt>
<dd><p>Push the arguments onto the editing buffer stack, separated by spaces.
</p>
</dd>
</dl>
<p>If any of ‘<tt>-m</tt>’, ‘<tt>-o</tt>’ or ‘<tt>-O</tt>’ are used in combination with
‘<tt>-f</tt>’ and there are no arguments (after the removal process in the
case of ‘<tt>-m</tt>’) then nothing is printed.
</p>
<a name="index-printf"></a>
</dd>
<dt><tt>printf</tt> [ -v <var>name</var> ] <var>format</var> [ <var>arg</var> ... ]</dt>
<dd><p>Print the arguments according to the format specification. Formatting
rules are the same as used in C. The same escape sequences as for <tt>echo</tt>
are recognised in the format. All C conversion specifications ending in
one of <tt>csdiouxXeEfgGn</tt> are handled. In addition to this, ‘<tt>%b</tt>’ can be
used instead of ‘<tt>%s</tt>’ to cause escape sequences in the argument to be
recognised and ‘<tt>%q</tt>’ can be used to quote the argument in such a way
that allows it to be reused as shell input. With the numeric format
specifiers, if the corresponding argument starts with a quote character,
the numeric value of the following character is used as the number to
print; otherwise the argument is evaluated as an arithmetic expression. See
<a href="Arithmetic-Evaluation.html#Arithmetic-Evaluation">Arithmetic Evaluation</a>
for a description of arithmetic
expressions. With ‘<tt>%n</tt>’, the corresponding argument is taken as an
identifier which is created as an integer parameter.
</p>
<p>Normally, conversion specifications are applied to each argument in order
but they can explicitly specify the <var>n</var>th argument is to be used by
replacing ‘<tt>%</tt>’ by ‘<tt>%</tt><var>n</var><tt>$</tt>’ and ‘<tt>*</tt>’ by ‘<tt>*</tt><var>n</var><tt>$</tt>’.
It is recommended that you do not mix references of this explicit style
with the normal style and the handling of such mixed styles may be subject
to future change.
</p>
<p>If arguments remain unused after formatting, the format string is reused
until all arguments have been consumed. With the <tt>print</tt> builtin, this
can be suppressed by using the <tt>-r</tt> option. If more arguments are
required by the format than have been specified, the behaviour is as if
zero or an empty string had been specified as the argument.
</p>
<p>The <tt>-v</tt> option causes the output to be stored as the value of the
parameter <var>name</var>, instead of printed. If <var>name</var> is an array and
the format string is reused when consuming arguments then one
array element will be used for each use of the format string.
</p>
<a name="index-pushd"></a>
<a name="index-PUSHD_005fTO_005fHOME_002c-use-of"></a>
<a name="index-PUSHD_005fMINUS_002c-use-of-2"></a>
<a name="index-CDABLE_005fVARS_002c-use-of"></a>
<a name="index-PUSHD_005fSILENT_002c-use-of"></a>
</dd>
<dt><tt>pushd</tt> [ <tt>-qsLP</tt> ] [ <var>arg</var> ]</dt>
<dt><tt>pushd</tt> [ <tt>-qsLP</tt> ] <var>old</var> <var>new</var></dt>
<dt><tt>pushd</tt> [ <tt>-qsLP</tt> ] {<tt>+</tt>|<tt>-</tt>}<var>n</var></dt>
<dd><p>Change the current directory, and push the old current directory
onto the directory stack. In the first form, change the
current directory to <var>arg</var>.
If <var>arg</var> is not specified, change to the second directory
on the stack (that is, exchange the top two entries), or
change to <tt>$HOME</tt> if the <tt>PUSHD_TO_HOME</tt>
option is set or if there is only one entry on the stack.
Otherwise, <var>arg</var> is interpreted as it would be by <tt>cd</tt>.
The meaning of <var>old</var> and <var>new</var> in the second form is also
the same as for <tt>cd</tt>.
</p>
<p>The third form of <tt>pushd</tt> changes directory by rotating the
directory list. An argument of the form ‘<tt>+</tt><var>n</var>’ identifies a stack
entry by counting from the left of the list shown by the <tt>dirs</tt>
command, starting with zero. An argument of the form ‘<tt>-</tt><var>n</var>’ counts
from the right. If the <tt>PUSHD_MINUS</tt> option is set, the meanings
of ‘<tt>+</tt>’ and ‘<tt>-</tt>’ in this context are swapped.
</p>
<p>If the <tt>-q</tt> (quiet) option is specified, the hook function <tt>chpwd</tt>
and the functions in the array <tt>$chpwd_functions</tt> are not called,
and the new directory stack is not printed. This is useful for calls to
<tt>pushd</tt> that do not change the environment seen by an interactive user.
</p>
<p>If the option <tt>-q</tt> is not specified and the shell option <tt>PUSHD_SILENT</tt>
is not set, the directory stack will be printed after a <tt>pushd</tt> is
performed.
</p>
<p>The options <tt>-s</tt>, <tt>-L</tt> and <tt>-P</tt> have the same meanings as for the
<tt>cd</tt> builtin.
</p>
<a name="index-pushln"></a>
</dd>
<dt><tt>pushln</tt> [ <var>arg</var> ... ]</dt>
<dd><p>Equivalent to <tt>print -nz</tt>.
</p>
<a name="index-pwd"></a>
<a name="index-CHASE_005fLINKS_002c-use-of"></a>
</dd>
<dt><tt>pwd</tt> [ <tt>-rLP</tt> ]</dt>
<dd><p>Print the absolute pathname of the current working directory.
If the <tt>-r</tt> or the <tt>-P</tt> flag is specified, or the <tt>CHASE_LINKS</tt>
option is set and the <tt>-L</tt> flag is not given, the printed path will not
contain symbolic links.
</p>
<a name="index-r"></a>
</dd>
<dt><tt>r</tt></dt>
<dd><p>Same as <tt>fc -e -</tt>.
</p>
<a name="index-read"></a>
<a name="index-IFS_002c-use-of-2"></a>
</dd>
<dt><tt>read </tt>[ <tt>-rszpqAclneE</tt> ] [ <tt>-t</tt> [ <var>num</var> ] ] [ <tt>-k</tt> [ <var>num</var> ] ] [ <tt>-d</tt> <var>delim</var> ]</dt>
<dt><tt> </tt>[ <tt>-u</tt> <var>n</var> ] [ <var>name</var>[<tt>?</tt><var>prompt</var>] ] [ <var>name</var> ... ]</dt>
<dd><a name="index-REPLY_002c-use-of-2"></a>
<a name="index-reply_002c-use-of-1"></a>
<p>Read one line and break it into fields using the characters
in <tt>$IFS</tt> as separators, except as noted below.
The first field is assigned to the first <var>name</var>, the second field
to the second <var>name</var>, etc., with leftover
fields assigned to the last <var>name</var>.
If <var>name</var> is omitted then
<tt>REPLY</tt> is used for scalars and <tt>reply</tt> for arrays.
</p>
<dl compact="compact">
<dt><tt>-r</tt></dt>
<dd><p>Raw mode: a ‘<tt>\</tt>’ at the end of a line does not signify line
continuation and backslashes in the line don’t quote the following
character and are not removed.
</p>
</dd>
<dt><tt>-s</tt></dt>
<dd><p>Don’t echo back characters if reading from the terminal.
</p>
</dd>
<dt><tt>-q</tt></dt>
<dd><p>Read only one character from the terminal and set <var>name</var> to
‘<tt>y</tt>’ if this character was ‘<tt>y</tt>’ or ‘<tt>Y</tt>’ and to ‘<tt>n</tt>’ otherwise.
With this flag set the return status is zero only if the character was
‘<tt>y</tt>’ or ‘<tt>Y</tt>’. This option may be used with a timeout (see <tt>-t</tt>); if
the read times out, or encounters end of file, status 2 is returned. Input is
read from the terminal unless one of <tt>-u</tt> or <tt>-p</tt> is present. This option
may also be used within zle widgets.
</p>
</dd>
<dt><tt>-k</tt> [ <var>num</var> ]</dt>
<dd><p>Read only one (or <var>num</var>) characters. All are assigned to the first
<var>name</var>, without word splitting. This flag is ignored when <tt>-q</tt> is
present. Input is read from the terminal unless one of <tt>-u</tt> or <tt>-p</tt>
is present. This option may also be used within zle widgets.
</p>
<p>Note that despite the mnemonic ‘key’ this option does read full
characters, which may consist of multiple bytes if the option
<tt>MULTIBYTE</tt> is set.
</p>
</dd>
<dt><tt>-z</tt></dt>
<dd><p>Read one entry from the editor buffer stack and assign it to the first
<var>name</var>, without word splitting. Text is pushed onto the stack with
‘<tt>print -z</tt>’ or with <tt>push-line</tt> from the line editor (see
<a href="Zsh-Line-Editor.html#Zsh-Line-Editor">Zsh Line Editor</a>). This flag is ignored when the <tt>-k</tt> or <tt>-q</tt> flags are present.
</p>
</dd>
<dt><tt>-e</tt></dt>
<dt><tt>-E</tt></dt>
<dd><p>The input read is printed (echoed) to the standard output. If the <tt>-e</tt>
flag is used, no input is assigned to the parameters.
</p>
</dd>
<dt><tt>-A</tt></dt>
<dd><p>The first <var>name</var> is taken as the name of an array and all words are
assigned to it.
</p>
</dd>
<dt><tt>-c</tt></dt>
<dt><tt>-l</tt></dt>
<dd><p>These flags are allowed only if called inside a
function used for completion (specified with the <tt>-K</tt> flag to
<tt>compctl</tt>). If the <tt>-c</tt> flag is given, the words of the
current command are read. If the <tt>-l</tt> flag is given, the whole
line is assigned as a scalar. If both flags are present, <tt>-l</tt>
is used and <tt>-c</tt> is ignored.
</p>
</dd>
<dt><tt>-n</tt></dt>
<dd><p>Together with <tt>-c</tt>, the number of the word the cursor is on is
read. With <tt>-l</tt>, the index of the character the cursor is on is
read. Note that the command name is word number 1, not word 0,
and that when the cursor is at the end of the line, its character
index is the length of the line plus one.
</p>
</dd>
<dt><tt>-u</tt> <var>n</var></dt>
<dd><p>Input is read from file descriptor <var>n</var>.
</p>
</dd>
<dt><tt>-p</tt></dt>
<dd><p>Input is read from the coprocess.
</p>
</dd>
<dt><tt>-d</tt> <var>delim</var></dt>
<dd><p>Input is terminated by the first character of <var>delim</var> instead of
by newline.
</p>
</dd>
<dt><tt>-t</tt> [ <var>num</var> ]</dt>
<dd><p>Test if input is available before attempting to read. If <var>num</var>
is present, it must begin with a digit and will be evaluated
to give a number of seconds, which may be a floating point number;
in this case the read times out if input is not available within this
time. If <var>num</var> is not present, it is taken to be zero, so that
<tt>read</tt> returns immediately if no input is available.
If no input is available, return status 1 and do not set any variables.
</p>
<p>This option is not available when reading from the editor buffer with
<tt>-z</tt>, when called from within completion with <tt>-c</tt> or <tt>-l</tt>, with
<tt>-q</tt> which clears the input queue before reading, or within zle where
other mechanisms should be used to test for input.
</p>
<p>Note that read does not attempt to alter the input processing mode. The
default mode is canonical input, in which an entire line is read at a time,
so usually ‘<tt>read -t</tt>’ will not read anything until an entire line has
been typed. However, when reading from the terminal with <tt>-k</tt>
input is processed one key at a time; in this case, only availability of
the first character is tested, so that e.g. ‘<tt>read -t -k 2</tt>’ can still
block on the second character. Use two instances of ‘<tt>read -t -k</tt>’ if
this is not what is wanted.
</p>
</dd>
</dl>
<p>If the first argument contains a ‘<tt>?</tt>’, the remainder of this
word is used as a <var>prompt</var> on standard error when the shell
is interactive.
</p>
<p>The value (exit status) of <tt>read</tt> is 1 when an end-of-file is
encountered, or when <tt>-c</tt> or <tt>-l</tt> is present and the command is
not called from a <tt>compctl</tt> function, or as described for <tt>-q</tt>.
Otherwise the value is 0.
</p>
<p>The behavior of some combinations of the <tt>-k</tt>, <tt>-p</tt>, <tt>-q</tt>, <tt>-u</tt>
and <tt>-z</tt> flags is undefined. Presently <tt>-q</tt> cancels all the others,
<tt>-p</tt> cancels <tt>-u</tt>, <tt>-k</tt> cancels <tt>-z</tt>, and otherwise <tt>-z</tt>
cancels both <tt>-p</tt> and <tt>-u</tt>.
</p>
<p>The <tt>-c</tt> or <tt>-l</tt> flags cancel any and all of <tt>-kpquz</tt>.
</p>
<a name="index-parameters_002c-marking-readonly"></a>
</dd>
<dt><tt>readonly</tt></dt>
<dd><p>Same as <tt>typeset -r</tt>. With the <tt>POSIX_BUILTINS</tt> option set, same
as <tt>typeset -gr</tt>.
</p>
<a name="index-rehash"></a>
</dd>
<dt><tt>rehash</tt></dt>
<dd><p>Same as <tt>hash -r</tt>.
</p>
<a name="index-return"></a>
<a name="index-functions_002c-returning-from"></a>
</dd>
<dt><tt>return</tt> [ <var>n</var> ]</dt>
<dd><p>Causes a shell function or ‘<tt>.</tt>’ script to return to
the invoking script with the return status specified by
an arithmetic expression <var>n</var>. If <var>n</var>
is omitted, the return status is that of the last command
executed.
</p>
<p>If <tt>return</tt> was executed from a trap in a <tt>TRAP</tt><var>NAL</var> function,
the effect is different for zero and non-zero return status. With zero
status (or after an implicit return at the end of the trap), the shell
will return to whatever it was previously processing; with a non-zero
status, the shell will behave as interrupted except that the return
status of the trap is retained. Note that the numeric value of the signal
which caused the trap is passed as the first argument, so the statement
‘<tt>return $((128+$1))</tt>’ will return the same status as if the signal
had not been trapped.
</p>
</dd>
<dt><tt>sched</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fsched-Module">The zsh/sched Module</a>.
</p>
<a name="index-set"></a>
<a name="index-parameters_002c-listing"></a>
<a name="index-parameters_002c-positional"></a>
<a name="index-parameters_002c-setting-array"></a>
<a name="index-array-parameters_002c-setting"></a>
<a name="index-KSH_005fARRAYS_002c-use-of-1"></a>
</dd>
<dt><tt>set </tt>[ {<tt>+</tt>|<tt>-</tt>}<var>options</var> | {<tt>+</tt>|<tt>-</tt>}<tt>o</tt> [ <var>option_name</var> ] ] ... [ {<tt>+</tt>|<tt>-</tt>}<tt>A</tt> [ <var>name</var> ] ]</dt>
<dt><tt> </tt>[ <var>arg</var> ... ]</dt>
<dd><p>Set the options for the shell and/or set the positional parameters, or
declare and set an array. If the <tt>-s</tt> option is given, it causes the
specified arguments to be sorted before assigning them to the positional
parameters (or to the array <var>name</var> if <tt>-A</tt> is used). With <tt>+s</tt>
sort arguments in descending order. For the meaning of the other flags, see
<a href="Options.html#Options">Options</a>. Flags may be specified by name using the <tt>-o</tt> option. If no option
name is supplied with <tt>-o</tt>, the current option states are printed: see
the description of <tt>setopt</tt> below for more information on the format.
With <tt>+o</tt> they are printed in a form that can be used as input
to the shell.
</p>
<p>If the <tt>-A</tt> flag is specified, <var>name</var> is set to an array containing
the given <var>arg</var>s; if no <var>name</var> is specified, all arrays are printed
together with their values.
</p>
<p>If <tt>+A</tt> is used and <var>name</var> is an array, the
given arguments will replace the initial elements of that array; if no
<var>name</var> is specified, all arrays are printed without their values.
</p>
<p>The behaviour of arguments after <tt>-A</tt> <var>name</var> or <tt>+A</tt> <var>name</var>
depends on whether the option <tt>KSH_ARRAYS</tt> is set. If it is not set, all
arguments following <var>name</var> are treated as values for the array,
regardless of their form. If the option is set, normal option processing
continues at that point; only regular arguments are treated as values for
the array. This means that
</p>
<div class="example">
<pre class="example">set -A array -x -- foo
</pre></div>
<p>sets <tt>array</tt> to ‘<tt>-x -</tt><tt>- foo</tt>’ if <tt>KSH_ARRAYS</tt> is not set, but sets
the array to <tt>foo</tt> and turns on the option ‘<tt>-x</tt>’ if it is set.
</p>
<p>If the <tt>-A</tt> flag is not present, but there are arguments beyond the
options, the positional parameters are set. If the option list (if any)
is terminated by ‘<tt>-</tt><tt>-</tt>’, and there are no further arguments, the
positional parameters will be unset.
</p>
<p>If no arguments and no ‘<tt>-</tt><tt>-</tt>’ are given, then the names and values of
all parameters are printed on the standard output. If the only argument is
‘<tt>+</tt>’, the names of all parameters are printed.
</p>
<p>For historical reasons, ‘<tt>set -</tt>’ is treated as ‘<tt>set +xv</tt>’
and ‘<tt>set -</tt> <var>args</var>’ as ‘<tt>set +xv --</tt> <var>args</var>’ when in
any other emulation mode than zsh’s native mode.
</p>
</dd>
<dt><tt>setcap</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fcap-Module">The zsh/cap Module</a>.
</p>
<a name="index-setopt"></a>
<a name="index-options_002c-setting"></a>
</dd>
<dt><tt>setopt</tt> [ {<tt>+</tt>|<tt>-</tt>}<var>options</var> | {<tt>+</tt>|<tt>-</tt>}<tt>o</tt> <var>option_name</var> ] [ <tt>-m</tt> ] [ <var>name</var> ... ]</dt>
<dd><p>Set the options for the shell. All options specified either
with flags or by name are set.
</p>
<p>If no arguments are supplied, the names of all options currently set are
printed. The form is chosen so as to minimize the differences from the
default options for the current emulation (the default emulation being
native <tt>zsh</tt>, shown as <tt><Z></tt> in
<a href="Options.html#Description-of-Options">Description of Options</a>).
Options that are on by default for the emulation are
shown with the prefix <tt>no</tt> only if they are off, while other options are
shown without the prefix <tt>no</tt> and only if they are on. In addition to
options changed from the default state by the user, any options activated
automatically by the shell (for example, <tt>SHIN_STDIN</tt> or <tt>INTERACTIVE</tt>)
will be shown in the list. The format is further modified by the option
<tt>KSH_OPTION_PRINT</tt>, however the rationale for choosing options with
or without the <tt>no</tt> prefix remains the same in this case.
</p>
<p>If the <tt>-m</tt> flag is given the arguments are taken as patterns
(which should be quoted to protect them from filename expansion), and all
options with names matching these patterns are set.
</p>
<p>Note that a bad option name does not cause execution of subsequent shell
code to be aborted; this is behaviour is different from that of ‘<tt>set
-o</tt>’. This is because <tt>set</tt> is regarded as a special builtin by the
POSIX standard, but <tt>setopt</tt> is not.
</p>
<a name="index-shift"></a>
<a name="index-parameters_002c-positional-1"></a>
</dd>
<dt><tt>shift</tt> [ <tt>-p</tt> ] [ <var>n</var> ] [ <var>name</var> ... ]</dt>
<dd><p>The positional parameters <tt>${</tt><var>n</var>+1<tt>}</tt> ... are renamed
to <tt>$1</tt> ..., where <var>n</var> is an arithmetic expression that
defaults to 1.
If any <var>name</var>s are given then the arrays with these names are
shifted instead of the positional parameters.
</p>
<p>If the option <tt>-p</tt> is given arguments are instead removed (popped)
from the end rather than the start of the array.
</p>
<a name="index-source"></a>
</dd>
<dt><tt>source</tt> <var>file</var> [ <var>arg</var> ... ]</dt>
<dd><p>Same as ‘<tt>.</tt>’, except that the current directory is always searched and
is always searched first, before directories in <tt>$path</tt>.
</p>
</dd>
<dt><tt>stat</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fstat-Module">The zsh/stat Module</a>.
</p>
<a name="index-suspend"></a>
<a name="index-shell_002c-suspending"></a>
<a name="index-suspending-the-shell"></a>
</dd>
<dt><tt>suspend</tt> [ <tt>-f</tt> ]</dt>
<dd><p>Suspend the execution of the shell (send it a <tt>SIGTSTP</tt>)
until it receives a <tt>SIGCONT</tt>.
Unless the <tt>-f</tt> option is given, this will refuse to suspend a login shell.
</p>
<a name="index-test"></a>
</dd>
<dt><tt>test</tt> [ <var>arg</var> ... ]</dt>
<dt><tt>[</tt> [ <var>arg</var> ... ] <tt>]</tt></dt>
<dd><p>Like the system version of <tt>test</tt>. Added for compatibility;
use conditional expressions instead (see <a href="Conditional-Expressions.html#Conditional-Expressions">Conditional Expressions</a>).
The main differences between the conditional expression syntax and the
<tt>test</tt> and <tt>[</tt> builtins are: these commands are not handled
syntactically, so for example an empty variable expansion may cause an
argument to be omitted; syntax errors cause status 2 to be returned instead
of a shell error; and arithmetic operators expect integer arguments rather
than arithmetic expressions.
</p>
<p>The command attempts to implement POSIX and its extensions where these
are specified. Unfortunately there are intrinsic ambiguities in
the syntax; in particular there is no distinction between test operators
and strings that resemble them. The standard attempts to resolve these
for small numbers of arguments (up to four); for five or more arguments
compatibility cannot be relied on. Users are urged wherever possible to
use the ‘<tt>[[</tt>’ test syntax which does not have these ambiguities.
</p>
<a name="index-times"></a>
<a name="index-shell_002c-timing"></a>
<a name="index-timing-the-shell"></a>
</dd>
<dt><tt>times</tt></dt>
<dd><p>Print the accumulated user and system times for the shell
and for processes run from the shell.
</p>
<a name="index-trap"></a>
<a name="index-signals_002c-trapping-1"></a>
<a name="index-trapping-signals-1"></a>
</dd>
<dt><tt>trap</tt> [ <var>arg</var> ] [ <var>sig</var> ... ]</dt>
<dd><p><var>arg</var> is a series of commands (usually quoted to protect it from
immediate evaluation by the shell) to be read and executed when the shell
receives any of the signals specified by one or more <var>sig</var> args.
Each <var>sig</var> can be given as a number,
or as the name of a signal either with or without the string <tt>SIG</tt>
in front (e.g. 1, HUP, and SIGHUP are all the same signal).
</p>
<p>If <var>arg</var> is ‘<tt>-</tt>’, then the specified signals are reset to their
defaults, or, if no <var>sig</var> args are present, all traps are reset.
</p>
<p>If <var>arg</var> is an empty string, then the specified signals
are ignored by the shell (and by the commands it invokes).
</p>
<p>If <var>arg</var> is omitted but one or more <var>sig</var> args are provided (i.e.
the first argument is a valid signal number or name), the effect is the
same as if <var>arg</var> had been specified as ‘<tt>-</tt>’.
</p>
<p>The <tt>trap</tt> command with no arguments prints a list of commands
associated with each signal.
</p>
<p>If <var>sig</var> is <tt>ZERR</tt> then <var>arg</var> will be executed
after each command with a nonzero exit status. <tt>ERR</tt> is an alias
for <tt>ZERR</tt> on systems that have no <tt>SIGERR</tt> signal (this is the
usual case).
</p>
<p>If <var>sig</var> is <tt>DEBUG</tt> then <var>arg</var> will be executed
before each command if the option <tt>DEBUG_BEFORE_CMD</tt> is set
(as it is by default), else after each command. Here, a ‘command’ is
what is described as a ‘sublist’ in the shell grammar, see
<a href="Shell-Grammar.html#Simple-Commands-_0026-Pipelines">Simple Commands & Pipelines</a>.
If <tt>DEBUG_BEFORE_CMD</tt> is set various additional features are available.
First, it is possible to skip the next command by setting the option
<tt>ERR_EXIT</tt>; see the description of the <tt>ERR_EXIT</tt> option in
<a href="Options.html#Description-of-Options">Description of Options</a>. Also, the shell parameter
<tt>ZSH_DEBUG_CMD</tt> is set to the string corresponding to the command
to be executed following the trap. Note that this string is reconstructed
from the internal format and may not be formatted the same way as the
original text. The parameter is unset after the trap is executed.
</p>
<p>If <var>sig</var> is <tt>0</tt> or <tt>EXIT</tt>
and the <tt>trap</tt> statement is executed inside the body of a function,
then the command <var>arg</var> is executed after the function completes.
The value of <tt>$?</tt> at the start of execution is the exit status of the
shell or the return status of the function exiting.
If <var>sig</var> is <tt>0</tt> or <tt>EXIT</tt>
and the <tt>trap</tt> statement is not executed inside the body of a function,
then the command <var>arg</var> is executed when the shell terminates; the
trap runs before any <tt>zshexit</tt> hook functions.
</p>
<p><tt>ZERR</tt>, <tt>DEBUG</tt>, and <tt>EXIT</tt> traps are not executed inside other
traps. <tt>ZERR</tt> and <tt>DEBUG</tt> traps are kept within subshells, while
other traps are reset.
</p>
<p>Note that traps defined with the <tt>trap</tt> builtin are slightly different
from those defined as ‘<tt>TRAP</tt><var>NAL</var> () { ... }’, as the latter have
their own function environment (line numbers, local variables, etc.) while
the former use the environment of the command in which they were called.
For example,
</p>
<div class="example">
<pre class="example">trap 'print $LINENO' DEBUG
</pre></div>
<p>will print the line number of a command executed after it has run, while
</p>
<div class="example">
<pre class="example">TRAPDEBUG() { print $LINENO; }
</pre></div>
<p>will always print the number zero.
</p>
<p>Alternative signal names are allowed as described under <tt>kill</tt> above.
Defining a trap under either name causes any trap under an alternative
name to be removed. However, it is recommended that for consistency
users stick exclusively to one name or another.
</p>
<a name="index-true"></a>
<a name="index-doing-nothing_002c-successfully"></a>
</dd>
<dt><tt>true</tt> [ <var>arg</var> ... ]</dt>
<dd><p>Do nothing and return an exit status of 0.
</p>
<a name="index-ttyctl"></a>
<a name="index-tty_002c-freezing"></a>
</dd>
<dt><tt>ttyctl</tt> [ <tt>-fu</tt> ]</dt>
<dd><p>The <tt>-f</tt> option freezes the tty (i.e. terminal or terminal emulator), and
<tt>-u</tt> unfreezes it.
When the tty is frozen, no changes made to the tty settings by
external programs will be honored by the shell, except for changes in the
size of the screen; the shell will
simply reset the settings to their previous values as soon as each
command exits or is suspended. Thus, <tt>stty</tt> and similar programs have
no effect when the tty is frozen. Freezing the tty does not cause
the current state to be remembered: instead, it causes future changes
to the state to be blocked.
</p>
<p>Without options it reports whether the terminal is frozen or not.
</p>
<p>Note that, regardless of whether the tty is frozen or not, the
shell needs to change the settings when the line editor starts, so
unfreezing the tty does not guarantee settings made on the
command line are preserved. Strings of commands run between
editing the command line will see a consistent tty state.
See also the shell variable <tt>STTY</tt> for a means of initialising
the tty before running external commands.
</p>
<a name="index-type"></a>
</dd>
<dt><tt>type</tt> [ <tt>-wfpamsS</tt> ] <var>name</var> ...</dt>
<dd><p>Equivalent to <tt>whence -v</tt>.
</p>
<a name="index-typeset"></a>
<a name="index-parameters_002c-setting"></a>
<a name="index-parameters_002c-declaring"></a>
</dd>
<dt><tt>typeset </tt>[ {<tt>+</tt>|<tt>-</tt>}<tt>AHUaghlmrtux</tt> ] [ {<tt>+</tt>|<tt>-</tt>}<tt>EFLRZip</tt> [ <var>n</var> ] ]</dt>
<dt><tt> </tt>[ <tt>+</tt> ] [ <var>name</var>[<tt>=</tt><var>value</var>] ... ]</dt>
<dt><tt>typeset </tt><tt>-T</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>Uglrux</tt> ] [ {<tt>+</tt>|<tt>-</tt>}<tt>LRZp</tt> [ <var>n</var> ] ]</dt>
<dt><tt> </tt>[ <tt>+</tt> | <var>SCALAR</var>[<tt>=</tt><var>value</var>] <var>array</var>[<tt>=(</tt><var>value</var> ...<tt>)</tt>] [ <var>sep</var> ] ]</dt>
<dt><tt>typeset</tt> <tt>-f</tt> [ {<tt>+</tt>|<tt>-</tt>}<tt>TUkmtuz</tt> ] [ <tt>+</tt> ] [ <var>name</var> ... ]</dt>
<dd><p>Set or display attributes and values for shell parameters.
</p>
<p>Except as noted below for control flags that change the behavior,
a parameter is created for each <var>name</var> that does not already refer
to one. When inside a function, a new parameter is created for every
<var>name</var> (even those that already exist), and is unset again when the
function completes. See
<a href="Parameters.html#Local-Parameters">Local Parameters</a>. The same rules apply to special shell parameters, which
retain their special attributes when made local.
</p>
<p>For each <var>name</var><tt>=</tt><var>value</var> assignment, the parameter
<var>name</var> is set to <var>value</var>.
</p>
<p>If the shell option <tt>TYPESET_SILENT</tt> is not set, for each remaining
<var>name</var> that refers to a parameter that is already set, the name and
value of the parameter are printed in the form of an assignment.
Nothing is printed for newly-created parameters, or when any attribute
flags listed below are given along with the <var>name</var>. Using
‘<tt>+</tt>’ instead of minus to introduce an attribute turns it off.
</p>
<p>If no <var>name</var> is present, the names and values of all parameters are
printed. In this case the attribute flags restrict the display to only
those parameters that have the specified attributes, and using ‘<tt>+</tt>’
rather than ‘<tt>-</tt>’ to introduce the flag suppresses printing of the values
of parameters when there is no parameter name.
</p>
<p>All forms of the command handle scalar assignment. Array assignment is
possible if any of the reserved words <tt>declare</tt>, <tt>export</tt>, <tt>float</tt>,
<tt>integer</tt>, <tt>local</tt>, <tt>readonly</tt> or <tt>typeset</tt> is matched when the
line is parsed (N.B. not when it is executed). In this case the arguments
are parsed as assignments, except that the ‘<tt>+=</tt>’ syntax and the
<tt>GLOB_ASSIGN</tt> option are not supported, and scalar values after <tt>=</tt>
are <em>not</em> split further into words, even if expanded (regardless of the
setting of the <tt>KSH_TYPESET</tt> option; this option is obsolete).
</p>
<p>Examples of the differences between command and reserved word parsing:
</p>
<div class="example">
<pre class="example"># Reserved word parsing
typeset svar=$(echo one word) avar=(several words)
</pre></div>
<p>The above creates a scalar parameter <tt>svar</tt> and an array
parameter <tt>avar</tt> as if the assignments had been
</p>
<div class="example">
<pre class="example">svar="one word"
avar=(several words)
</pre></div>
<p>On the other hand:
</p>
<div class="example">
<pre class="example"># Normal builtin interface
builtin typeset svar=$(echo two words)
</pre></div>
<p>The <tt>builtin</tt> keyword causes the above to use the standard builtin
interface to <tt>typeset</tt> in which argument parsing is performed in the same
way as for other commands. This example creates a scalar <tt>svar</tt>
containing the value <tt>two</tt> and another scalar parameter <tt>words</tt> with
no value. An array value in this case would either cause an error or be
treated as an obscure set of glob qualifiers.
</p>
<p>Arbitrary arguments are allowed if they take the form of assignments
after command line expansion; however, these only perform scalar
assignment:
</p>
<div class="example">
<pre class="example">var='svar=val'
typeset $var
</pre></div>
<p>The above sets the scalar parameter <tt>svar</tt> to the value <tt>val</tt>.
Parentheses around the value within <tt>var</tt> would not cause array
assignment as they will be treated as ordinary characters when <tt>$var</tt>
is substituted. Any non-trivial expansion in the name part of the
assignment causes the argument to be treated in this fashion:
</p>
<div class="example">
<pre class="example">typeset {var1,var2,var3}=name
</pre></div>
<p>The above syntax is valid, and has the expected effect of setting the
three parameters to the same value, but the command line is parsed as
a set of three normal command line arguments to <tt>typeset</tt> after
expansion. Hence it is not possible to assign to multiple arrays by
this means.
</p>
<p>Note that each interface to any of the commands my be disabled
separately. For example, ‘<tt>disable -r typeset</tt>’ disables the reserved
word interface to <tt>typeset</tt>, exposing the builtin interface, while
‘<tt>disable typeset</tt>’ disables the builtin. Note that disabling the
reserved word interface for <tt>typeset</tt> may cause problems with the
output of ‘<tt>typeset -p</tt>’, which assumes the reserved word interface is
available in order to restore array and associative array values.
</p>
<p>Unlike parameter assignment statements, <tt>typeset</tt>’s exit status on an
assignment that involves a command substitution does not reflect the exit
status of the command substitution. Therefore, to test for an error in
a command substitution, separate the declaration of the parameter from its
initialization:
</p>
<div class="example">
<pre class="example"># WRONG
typeset var1=$(exit 1) || echo "Trouble with var1"
# RIGHT
typeset var1 && var1=$(exit 1) || echo "Trouble with var1"
</pre></div>
<p>To initialize a parameter <var>param</var> to a command output and mark it readonly,
use <tt>typeset -r </tt><var>param</var> or <tt>readonly </tt><var>param</var> after the parameter
assignment statement.
</p>
<p>If no attribute flags are given, and either no <var>name</var> arguments are
present or the flag <tt>+m</tt> is used, then each parameter name printed is
preceded by a list of the attributes of that parameter (<tt>array</tt>,
<tt>association</tt>, <tt>exported</tt>, <tt>float</tt>, <tt>integer</tt>, <tt>readonly</tt>,
or <tt>undefined</tt> for autoloaded parameters not yet loaded). If <tt>+m</tt> is
used with attribute flags, and all those flags are introduced with
<tt>+</tt>, the matching parameter names are printed but their values
are not.
</p>
<p>The following control flags change the behavior of <tt>typeset</tt>:
</p>
<dl compact="compact">
<dt><tt>+</tt></dt>
<dd><p>If ‘<tt>+</tt>’ appears by itself in a separate word as the last option,
then the names of all parameters (functions with <tt>-f</tt>) are printed, but
the values (function bodies) are not. No <var>name</var> arguments may appear,
and it is an error for any other options to follow ‘<tt>+</tt>’. The
effect of ‘<tt>+</tt>’ is as if all attribute flags which precede it were
given with a ‘<tt>+</tt>’ prefix. For example, ‘<tt>typeset -U +</tt>’ is
equivalent to ‘<tt>typeset +U</tt>’ and displays the names of all arrays having
the uniqueness attribute, whereas ‘<tt>typeset -f -U +</tt>’ displays the
names of all autoloadable functions. If <tt>+</tt> is the only option,
then type information (array, readonly, etc.) is also printed for each
parameter, in the same manner as ‘<tt>typeset +m "*"</tt>’.
</p>
</dd>
<dt><tt>-g</tt></dt>
<dd><p>The <tt>-g</tt> (global) means that any resulting parameter will not be
restricted to local scope. Note that this does not necessarily mean that
the parameter will be global, as the flag will apply to any existing
parameter (even if unset) from an enclosing function. This flag does not
affect the parameter after creation, hence it has no effect when listing
existing parameters, nor does the flag <tt>+g</tt> have any effect except in
combination with <tt>-m</tt> (see below).
</p>
</dd>
<dt><tt>-m</tt></dt>
<dd><p>If the <tt>-m</tt> flag is given the <var>name</var> arguments are taken as patterns
(use quoting to prevent these from being interpreted as file patterns).
With no attribute flags, all parameters (or functions with the <tt>-f</tt>
flag) with matching names are printed (the shell option <tt>TYPESET_SILENT</tt>
is not used in this case).
</p>
<p>If the <tt>+g</tt> flag is combined with <tt>-m</tt>, a new local parameter is
created for every matching parameter that is not already local. Otherwise
<tt>-m</tt> applies all other flags or assignments to the existing parameters.
</p>
<p>Except when assignments are made with <var>name</var><tt>=</tt><var>value</var>, using
<tt>+m</tt> forces the matching parameters and their attributes to be printed,
even inside a function. Note that <tt>-m</tt> is ignored if no patterns are
given, so ‘<tt>typeset -m</tt>’ displays attributes but ‘<tt>typeset -a +m</tt>’
does not.
</p>
</dd>
<dt><tt>-p</tt> [ <var>n</var> ]</dt>
<dd><p>If the <tt>-p</tt> option is given, parameters and values are printed in the
form of a typeset command with an assignment, regardless of other flags
and options. Note that the <tt>-H</tt> flag on parameters is respected; no
value will be shown for these parameters.
</p>
<p><tt>-p</tt> may be followed by an optional integer argument. Currently
only the value <tt>1</tt> is supported. In this case arrays and associative
arrays are printed with newlines between indented elements for
readability.
</p>
</dd>
<dt><tt>-T</tt> [ <var>scalar</var>[<tt>=</tt><var>value</var>] <var>array</var>[<tt>=(</tt><var>value</var> ...<tt>)</tt>] [ <var>sep</var> ] ]</dt>
<dd><p>This flag has a different meaning when used with <tt>-f</tt>; see below.
Otherwise the <tt>-T</tt> option requires zero, two, or three arguments to be
present. With no arguments, the list of parameters created in this
fashion is shown. With two or three arguments, the first two are the name
of a scalar and of an array parameter (in that order) that will be tied
together in the manner of <tt>$PATH</tt> and <tt>$path</tt>. The optional third
argument is a single-character separator which will be used to join the
elements of the array to form the scalar; if absent, a colon is used, as
with <tt>$PATH</tt>. Only the first character of the separator is significant;
any remaining characters are ignored. Multibyte characters are not
yet supported.
</p>
<p>Only one of the scalar and array parameters may be assigned an initial
value (the restrictions on assignment forms described above also apply).
</p>
<p>Both the scalar and the array may be manipulated as normal. If one is
unset, the other will automatically be unset too. There is no way of
untying the variables without unsetting them, nor of converting the type
of one of them with another <tt>typeset</tt> command; <tt>+T</tt> does not work,
assigning an array to <var>scalar</var> is an error, and assigning a scalar to
<var>array</var> sets it to be a single-element array.
</p>
<p>Note that both ‘<tt>typeset -xT ...</tt>’ and ‘<tt>export -T ...</tt>’ work, but
only the scalar will be marked for export. Setting the value using the
scalar version causes a split on all separators (which cannot be quoted).
It is possible to apply <tt>-T</tt> to two previously tied variables but with a
different separator character, in which case the variables remain joined
as before but the separator is changed.
</p>
</dd>
</dl>
<p>Attribute flags that transform the final value (<tt>-L</tt>, <tt>-R</tt>, <tt>-Z</tt>,
<tt>-l</tt>, <tt>-u</tt>) are only applied to the expanded value at the point
of a parameter expansion expression using ‘<tt>$</tt>’. They are not applied
when a parameter is retrieved internally by the shell for any purpose.
</p>
<p>The following attribute flags may be specified:
</p>
<dl compact="compact">
<dt><tt>-A</tt></dt>
<dd><p>The names refer to associative array parameters; see
<a href="Parameters.html#Array-Parameters">Array Parameters</a>.
</p>
</dd>
<dt><tt>-L</tt> [ <var>n</var> ]</dt>
<dd><p>Left justify and remove leading blanks from the value when the parameter
is expanded.
If <var>n</var> is nonzero, it defines the width of the field.
If <var>n</var> is zero, the width is determined by the width of the value of
the first assignment. In the case of numeric parameters, the length of the
complete value assigned to the parameter is used to determine the width,
not the value that would be output.
</p>
<p>The width is the count of characters, which may be multibyte characters
if the <tt>MULTIBYTE</tt> option is in effect. Note that the screen
width of the character is not taken into account; if this is required,
use padding with parameter expansion flags
<tt>${(ml</tt><var>...</var><tt>)</tt><var>...</var><tt>}</tt> as described in
‘Parameter Expansion Flags’ in
<a href="Expansion.html#Parameter-Expansion">Parameter Expansion</a>.
</p>
<p>When the parameter is expanded, it is filled on the right with
blanks or truncated if necessary to fit the field.
Note truncation can lead to unexpected results with numeric parameters.
Leading zeros are removed if the <tt>-Z</tt> flag is also set.
</p>
</dd>
<dt><tt>-R</tt> [ <var>n</var> ]</dt>
<dd><p>Similar to <tt>-L</tt>, except that right justification is used;
when the parameter is expanded, the field is left filled with
blanks or truncated from the end. May not be combined with the <tt>-Z</tt>
flag.
</p>
</dd>
<dt><tt>-U</tt></dt>
<dd><p>For arrays (but not for associative arrays), keep only the first
occurrence of each duplicated value. This may also be set for
colon-separated special parameters like <tt>PATH</tt> or <tt>FIGNORE</tt>, etc.
Note the flag takes effect on assignment, and the type of the
variable being assigned to is determinative; for variables with
shared values it is therefore recommended to set the flag for
all interfaces, e.g. ‘<tt>typeset -U PATH path</tt>’.
</p>
<p>This flag has a different meaning when used with <tt>-f</tt>; see below.
</p>
</dd>
<dt><tt>-Z</tt> [ <var>n</var> ]</dt>
<dd><p>Specially handled if set along with the <tt>-L</tt> flag.
Otherwise, similar to <tt>-R</tt>, except that leading zeros are used for
padding instead of blanks if the first non-blank character is a digit.
Numeric parameters are specially handled: they are always eligible
for padding with zeroes, and the zeroes are inserted at an appropriate
place in the output.
</p>
</dd>
<dt><tt>-a</tt></dt>
<dd><p>The names refer to array parameters. An array parameter may be
created this way, but it may be assigned to in the <tt>typeset</tt>
statement only if the reserved word form of <tt>typeset</tt> is enabled
(as it is by default). When displaying, both normal and associative
arrays are shown.
</p>
</dd>
<dt><tt>-f</tt></dt>
<dd><p>The names refer to functions rather than parameters. No assignments
can be made, and the only other valid flags are <tt>-t</tt>, <tt>-T</tt>, <tt>-k</tt>,
<tt>-u</tt>, <tt>-U</tt> and <tt>-z</tt>. The flag <tt>-t</tt> turns on execution tracing
for this function; the flag <tt>-T</tt> does the same, but turns off tracing
for any named (not anonymous) function called from the present one,
unless that function also
has the <tt>-t</tt> or <tt>-T</tt> flag. The <tt>-u</tt> and <tt>-U</tt> flags cause the
function to be marked for autoloading; <tt>-U</tt> also causes alias
expansion to be suppressed when the function is loaded. See the
description of the ‘<tt>autoload</tt>’ builtin for details.
</p>
<p>Note that the builtin <tt>functions</tt> provides the same basic capabilities
as <tt>typeset -f</tt> but gives access to a few extra options; <tt>autoload</tt>
gives further additional options for the case <tt>typeset -fu</tt> and
<tt>typeset -fU</tt>.
</p>
</dd>
<dt><tt>-h</tt></dt>
<dd><p>Hide: only useful for special parameters (those marked ‘<S>’ in the table in
<a href="Parameters.html#Parameters-Set-By-The-Shell">Parameters Set By The Shell</a>), and for local parameters with the same name as a special parameter,
though harmless for others. A special parameter with this attribute will
not retain its special effect when made local. Thus after ‘<tt>typeset -h
PATH</tt>’, a function containing ‘<tt>typeset PATH</tt>’ will create an ordinary
local parameter without the usual behaviour of <tt>PATH</tt>. Alternatively,
the local parameter may itself be given this attribute; hence inside a
function ‘<tt>typeset -h PATH</tt>’ creates an ordinary local parameter and the
special <tt>PATH</tt> parameter is not altered in any way. It is also possible
to create a local parameter using ‘<tt>typeset +h </tt><var>special</var>’, where the
local copy of <var>special</var> will retain its special properties regardless of
having the <tt>-h</tt> attribute. Global special parameters loaded from shell
modules (currently those in <tt>zsh/mapfile</tt> and <tt>zsh/parameter</tt>) are
automatically given the <tt>-h</tt> attribute to avoid name clashes.
</p>
</dd>
<dt><tt>-H</tt></dt>
<dd><p>Hide value: specifies that <tt>typeset</tt> will not display the value of the
parameter when listing parameters; the display for such parameters is
always as if the ‘<tt>+</tt>’ flag had been given. Use of the parameter is
in other respects normal, and the option does not apply if the parameter is
specified by name, or by pattern with the <tt>-m</tt> option. This is on by
default for the parameters in the <tt>zsh/parameter</tt> and <tt>zsh/mapfile</tt>
modules. Note, however, that unlike the <tt>-h</tt> flag this is also useful
for non-special parameters.
</p>
</dd>
<dt><tt>-i</tt> [ <var>n</var> ]</dt>
<dd><p>Use an internal integer representation. If <var>n</var> is nonzero it
defines the output arithmetic base, otherwise it is determined by the
first assignment. Bases from 2 to 36 inclusive are allowed.
</p>
</dd>
<dt><tt>-E</tt> [ <var>n</var> ]</dt>
<dd><p>Use an internal double-precision floating point representation. On output
the variable will be converted to scientific notation. If <var>n</var> is
nonzero it defines the number of significant figures to display; the
default is ten.
</p>
</dd>
<dt><tt>-F</tt> [ <var>n</var> ]</dt>
<dd><p>Use an internal double-precision floating point representation. On output
the variable will be converted to fixed-point decimal notation. If <var>n</var>
is nonzero it defines the number of digits to display after the decimal
point; the default is ten.
</p>
</dd>
<dt><tt>-l</tt></dt>
<dd><p>Convert the result to lower case whenever the parameter is expanded.
The value is <em>not</em> converted when assigned.
</p>
</dd>
<dt><tt>-r</tt></dt>
<dd><p>The given <var>name</var>s are marked readonly. Note that if <var>name</var> is a
special parameter, the readonly attribute can be turned on, but cannot then
be turned off.
</p>
<p>If the <tt>POSIX_BUILTINS</tt> option is set, the readonly attribute is
more restrictive: unset variables can be marked readonly and cannot then
be set; furthermore, the readonly attribute cannot be removed from any
variable. Note that in zsh (unlike other shells) it is still possible
to create a local variable of the same name as this is considered a
different variable (though this variable, too, can be marked readonly).
</p>
</dd>
<dt><tt>-t</tt></dt>
<dd><p>Tags the named parameters. Tags have no special meaning to the shell.
This flag has a different meaning when used with <tt>-f</tt>; see above.
</p>
</dd>
<dt><tt>-u</tt></dt>
<dd><p>Convert the result to upper case whenever the parameter is expanded.
The value is <em>not</em> converted when assigned.
This flag has a different meaning when used with <tt>-f</tt>; see above.
</p>
</dd>
<dt><tt>-x</tt></dt>
<dd><p>Mark for automatic export to the environment of subsequently
executed commands. If the option <tt>GLOBAL_EXPORT</tt> is set, this implies
the option <tt>-g</tt>, unless <tt>+g</tt> is also explicitly given; in other words
the parameter is not made local to the enclosing function. This is for
compatibility with previous versions of zsh.
</p>
</dd>
</dl>
<a name="index-ulimit"></a>
<a name="index-resource-limits-1"></a>
<a name="index-limits_002c-resource-1"></a>
</dd>
<dt><tt>ulimit</tt> [ <tt>-HSa</tt> ] [ { <tt>-bcdfiklmnpqrsTtvwx</tt> | <tt>-N</tt> <var>resource</var> } [ <var>limit</var> ] ... ]</dt>
<dd><p>Set or display resource limits of the shell and the processes started by
the shell. The value of <var>limit</var> can be a number in the unit specified
below or one of the values ‘<tt>unlimited</tt>’, which removes the limit on the
resource, or ‘<tt>hard</tt>’, which uses the current value of the hard limit on
the resource.
</p>
<p>By default, only soft limits are manipulated. If the <tt>-H</tt> flag
is given use hard limits instead of soft limits. If the <tt>-S</tt> flag is given
together with the <tt>-H</tt> flag set both hard and soft limits.
</p>
<p>If no options are used, the file size limit (<tt>-f</tt>) is assumed.
</p>
<p>If <var>limit</var> is omitted the current value of the specified resources are
printed. When more than one resource value is printed, the limit name and
unit is printed before each value.
</p>
<p>When looping over multiple resources, the shell will abort immediately if
it detects a badly formed argument. However, if it fails to set a limit
for some other reason it will continue trying to set the remaining limits.
</p>
<p>Not all the following resources are supported on all systems. Running
<tt>ulimit -a</tt> will show which are supported.
</p>
<dl compact="compact">
<dt><tt>-a</tt></dt>
<dd><p>Lists all of the current resource limits.
</p></dd>
<dt><tt>-b</tt></dt>
<dd><p>Socket buffer size in bytes (N.B. not kilobytes)
</p></dd>
<dt><tt>-c</tt></dt>
<dd><p>512-byte blocks on the size of core dumps.
</p></dd>
<dt><tt>-d</tt></dt>
<dd><p>Kilobytes on the size of the data segment.
</p></dd>
<dt><tt>-f</tt></dt>
<dd><p>512-byte blocks on the size of files written.
</p></dd>
<dt><tt>-i</tt></dt>
<dd><p>The number of pending signals.
</p></dd>
<dt><tt>-k</tt></dt>
<dd><p>The number of kqueues allocated.
</p></dd>
<dt><tt>-l</tt></dt>
<dd><p>Kilobytes on the size of locked-in memory.
</p></dd>
<dt><tt>-m</tt></dt>
<dd><p>Kilobytes on the size of physical memory.
</p></dd>
<dt><tt>-n</tt></dt>
<dd><p>open file descriptors.
</p></dd>
<dt><tt>-p</tt></dt>
<dd><p>The number of pseudo-terminals.
</p></dd>
<dt><tt>-q</tt></dt>
<dd><p>Bytes in POSIX message queues.
</p></dd>
<dt><tt>-r</tt></dt>
<dd><p>Maximum real time priority. On some systems where this
is not available, such as NetBSD, this has the same effect as <tt>-T</tt>
for compatibility with <tt>sh</tt>.
</p></dd>
<dt><tt>-s</tt></dt>
<dd><p>Kilobytes on the size of the stack.
</p></dd>
<dt><tt>-T</tt></dt>
<dd><p>The number of simultaneous threads available to the user.
</p></dd>
<dt><tt>-t</tt></dt>
<dd><p>CPU seconds to be used.
</p></dd>
<dt><tt>-u</tt></dt>
<dd><p>The number of processes available to the user.
</p></dd>
<dt><tt>-v</tt></dt>
<dd><p>Kilobytes on the size of virtual memory. On some systems this
refers to the limit called ‘address space’.
</p></dd>
<dt><tt>-w</tt></dt>
<dd><p>Kilobytes on the size of swapped out memory.
</p></dd>
<dt><tt>-x</tt></dt>
<dd><p>The number of locks on files.
</p></dd>
</dl>
<p>A resource may also be specified by integer in the form ‘<tt>-N</tt>
<var>resource</var>’, where <var>resource</var> corresponds to the integer defined for
the resource by the operating system. This may be used to set the limits
for resources known to the shell which do not correspond to option letters.
Such limits will be shown by number in the output of ‘<tt>ulimit -a</tt>’.
</p>
<p>The number may alternatively be out of the range of limits compiled into
the shell. The shell will try to read or write the limit anyway, and
will report an error if this fails.
</p>
<a name="index-umask-1"></a>
<a name="index-umask"></a>
</dd>
<dt><tt>umask</tt> [ <tt>-S</tt> ] [ <var>mask</var> ]</dt>
<dd><p>The umask is set to <var>mask</var>. <var>mask</var> can be either
an octal number or a symbolic value as described in man page chmod(1).
If <var>mask</var> is omitted, the current value is printed. The <tt>-S</tt>
option causes the mask to be printed as a symbolic value. Otherwise,
the mask is printed as an octal number. Note that in
the symbolic form the permissions you specify are those which are to be
allowed (not denied) to the users specified.
</p>
<a name="index-aliases_002c-removing"></a>
</dd>
<dt><tt>unalias</tt> [ <tt>-ams</tt> ] <var>name</var> ...</dt>
<dd><p>Removes aliases. This command works the same as <tt>unhash -a</tt>, except that
the <tt>-a</tt> option removes all regular or global aliases, or with <tt>-s</tt>
all suffix aliases: in this case no <var>name</var> arguments may appear. The
options <tt>-m</tt> (remove by pattern) and <tt>-s</tt> without <tt>-a</tt> (remove
listed suffix aliases) behave as for <tt>unhash -a</tt>. Note that
the meaning of <tt>-a</tt> is different between <tt>unalias</tt> and <tt>unhash</tt>.
</p>
<a name="index-functions_002c-removing"></a>
<a name="index-unfunction"></a>
</dd>
<dt><tt>unfunction</tt></dt>
<dd><p>Same as <tt>unhash -f</tt>.
</p>
<a name="index-unhash"></a>
</dd>
<dt><tt>unhash</tt> [ <tt>-adfms</tt> ] <var>name</var> ...</dt>
<dd><p>Remove the element named <var>name</var> from an internal hash table. The
default is remove elements from the command hash table. The <tt>-a</tt>
option causes <tt>unhash</tt> to remove regular or global aliases; note
when removing a global aliases that the argument must be quoted to prevent
it from being expanded before being passed to the command.
The <tt>-s</tt> option causes <tt>unhash</tt> to remove suffix aliases.
The <tt>-f</tt> option causes
<tt>unhash</tt> to remove shell functions. The <tt>-d</tt> options causes
<tt>unhash</tt> to remove named directories. If the <tt>-m</tt> flag is given
the arguments are taken as patterns (should be quoted) and all elements
of the corresponding hash table with matching names will be removed.
</p>
<a name="index-unlimit"></a>
<a name="index-resource-limits-2"></a>
<a name="index-limits_002c-resource-2"></a>
</dd>
<dt><tt>unlimit</tt> [ <tt>-hs</tt> ] <var>resource</var> ...</dt>
<dd><p>The resource limit for each <var>resource</var> is set to the hard limit.
If the <tt>-h</tt> flag is given and the shell has appropriate privileges,
the hard resource limit for each <var>resource</var> is removed.
The resources of the shell process are only changed if the <tt>-s</tt>
flag is given.
</p>
<p>The <tt>unlimit</tt> command is not made available by default when the
shell starts in a mode emulating another shell. It can be made available
with the command ‘<tt>zmodload -F zsh/rlimits b:unlimit</tt>’.
</p>
<a name="index-unset"></a>
<a name="index-parameters_002c-unsetting"></a>
</dd>
<dt><tt>unset</tt> [ <tt>-fmv</tt> ] <var>name</var> ...</dt>
<dd><p>Each named parameter is unset.
Local parameters remain local even if unset; they appear unset within scope,
but the previous value will still reappear when the scope ends.
</p>
<p>Individual elements of associative array parameters may be unset by using
subscript syntax on <var>name</var>, which should be quoted (or the entire command
prefixed with <tt>noglob</tt>) to protect the subscript from filename generation.
</p>
<p>If the <tt>-m</tt> flag is specified the arguments are taken as patterns (should
be quoted) and all parameters with matching names are unset. Note that this
cannot be used when unsetting associative array elements, as the subscript
will be treated as part of the pattern.
</p>
<p>The <tt>-v</tt> flag specifies that <var>name</var> refers to parameters. This is the
default behaviour.
</p>
<p><tt>unset -f</tt> is equivalent to <tt>unfunction</tt>.
</p>
<a name="index-unsetopt"></a>
<a name="index-options_002c-unsetting"></a>
</dd>
<dt><tt>unsetopt</tt> [ {<tt>+</tt>|<tt>-</tt>}<var>options</var> | {<tt>+</tt>|<tt>-</tt>}<tt>o</tt> <var>option_name</var> ] [ <var>name</var> ... ]</dt>
<dd><p>Unset the options for the shell. All options specified either
with flags or by name are unset. If no arguments are supplied,
the names of all options currently unset are printed.
If the <tt>-m</tt> flag is given the arguments are taken as patterns
(which should be quoted to preserve them from being interpreted as glob
patterns), and all options with names matching these patterns are unset.
</p>
</dd>
<dt><tt>vared</tt></dt>
<dd><p>See <a href="Zsh-Line-Editor.html#Zle-Builtins">Zle Builtins</a>.
</p>
<a name="index-wait"></a>
<a name="index-waiting-for-jobs"></a>
<a name="index-jobs_002c-waiting-for"></a>
</dd>
<dt><tt>wait</tt> [ <var>job</var> ... ]</dt>
<dd><p>Wait for the specified jobs or processes. If <var>job</var> is not given
then all currently active child processes are waited for.
Each <var>job</var> can be either a job specification or the process ID
of a job in the job table.
The exit status from this command is that of the job waited for.
</p>
<p>It is possible to wait for recent processes (specified by process ID,
not by job) that were running in the background even if the process has
exited. Typically the process ID will be recorded by capturing the
value of the variable <tt>$!</tt> immediately after the process has been
started. There is a limit on the number of process IDs remembered by
the shell; this is given by the value of the system configuration
parameter <tt>CHILD_MAX</tt>. When this limit is reached, older process IDs
are discarded, least recently started processes first.
</p>
<p>Note there is no protection against the process ID wrapping, i.e. if the
wait is not executed soon enough there is a chance the process waited
for is the wrong one. A conflict implies both process IDs have been
generated by the shell, as other processes are not recorded, and that
the user is potentially interested in both, so this problem is intrinsic
to process IDs.
</p>
<a name="index-whence"></a>
</dd>
<dt><tt>whence</tt> [ <tt>-vcwfpamsS</tt> ] [ <tt>-x</tt> <var>num</var> ] <var>name</var> ...</dt>
<dd><p>For each <var>name</var>, indicate how it would be interpreted if used as a
command name.
</p>
<p><tt>whence</tt> is most useful when <var>name</var> is only the last path component
of a command, i.e. does not include a ‘<tt>/</tt>’; in particular, pattern
matching only succeeds if just the non-directory component of the command is
passed.
</p>
<dl compact="compact">
<dt><tt>-v</tt></dt>
<dd><p>Produce a more verbose report.
</p>
</dd>
<dt><tt>-c</tt></dt>
<dd><p>Print the results in a <cite>csh</cite>-like format.
This takes precedence over <tt>-v</tt>.
</p>
</dd>
<dt><tt>-w</tt></dt>
<dd><p>For each <var>name</var>, print ‘<var>name</var><tt>:</tt> <var>word</var>’ where <var>word</var>
is one of <tt>alias</tt>, <tt>builtin</tt>, <tt>command</tt>, <tt>function</tt>,
<tt>hashed</tt>, <tt>reserved</tt> or <tt>none</tt>, according as <var>name</var>
corresponds to an alias, a built-in command, an external command, a
shell function, a command defined with the <tt>hash</tt> builtin, a
reserved word, or is not recognised. This takes precedence over
<tt>-v</tt> and <tt>-c</tt>.
</p>
</dd>
<dt><tt>-f</tt></dt>
<dd><p>Causes the contents of a shell function to be
displayed, which would otherwise not happen unless the <tt>-c</tt>
flag were used.
</p>
</dd>
<dt><tt>-p</tt></dt>
<dd><p>Do a path search for <var>name</var>
even if it is an alias, reserved word, shell function or builtin.
</p>
</dd>
<dt><tt>-a</tt></dt>
<dd><p>Do a search for all occurrences of <var>name</var>
throughout the command path.
Normally only the first occurrence is printed.
</p>
</dd>
<dt><tt>-m</tt></dt>
<dd><p>The arguments are taken as patterns (pattern characters should be
quoted), and the information is displayed for each command matching one
of these patterns.
</p>
</dd>
<dt><tt>-s</tt></dt>
<dd><p>If a pathname contains symlinks, print the symlink-free pathname as well.
</p>
</dd>
<dt><tt>-S</tt></dt>
<dd><p>As <tt>-s</tt>, but if the pathname had to be resolved by following
multiple symlinks, the intermediate steps are printed, too. The
symlink resolved at each step might be anywhere in the path.
</p>
</dd>
<dt><tt>-x</tt> <var>num</var></dt>
<dd><p>Expand tabs when outputting shell functions using the <tt>-c</tt> option.
This has the same effect as the <tt>-x</tt> option to the <tt>functions</tt>
builtin.
</p>
</dd>
</dl>
<a name="index-where"></a>
</dd>
<dt><tt>where</tt> [ <tt>-wpmsS</tt> ] [ <tt>-x</tt> <var>num</var> ] <var>name</var> ...</dt>
<dd><p>Equivalent to <tt>whence -ca</tt>.
</p>
<a name="index-which"></a>
</dd>
<dt><tt>which</tt> [ <tt>-wpamsS</tt> ] [ <tt>-x</tt> <var>num</var> ] <var>name</var> ...</dt>
<dd><p>Equivalent to <tt>whence -c</tt>.
</p>
<a name="index-zcompile"></a>
<a name="index-_002ezwc-files_002c-creation"></a>
<a name="index-compilation"></a>
</dd>
<dt><tt>zcompile</tt> [ <tt>-U</tt> ] [ <tt>-z</tt> | <tt>-k</tt> ] [ <tt>-R</tt> | <tt>-M</tt> ] <var>file</var> [ <var>name</var> ... ]</dt>
<dt><tt>zcompile</tt> <tt>-ca</tt> [ <tt>-m</tt> ] [ <tt>-R</tt> | <tt>-M</tt> ] <var>file</var> [ <var>name</var> ... ]</dt>
<dt><tt>zcompile -t</tt> <var>file</var> [ <var>name</var> ... ]</dt>
<dd><p>This builtin command can be used to compile functions or scripts,
storing the compiled form in a file, and to examine files containing
the compiled form. This allows faster autoloading of functions and
sourcing of scripts by avoiding parsing of the text when the files
are read.
</p>
<p>The first form (without the <tt>-c</tt>, <tt>-a</tt> or <tt>-t</tt> options) creates a
compiled file. If only the <var>file</var> argument is given, the
output file has the name ‘<var>file</var><tt>.zwc</tt>’ and will be placed in
the same directory as the <var>file</var>. The shell will load the compiled
file instead of the normal function file when the function
is autoloaded; see
<a href="Functions.html#Functions">Functions</a>
for a description of how autoloaded functions are searched. The
extension <tt>.zwc</tt> stands for ‘zsh word code’.
</p>
<a name="index-fpath_002c-with-zcompile"></a>
<p>If there is at least one <var>name</var> argument, all the named files
are compiled into the output <var>file</var> given as the first argument. If
<var>file</var> does not end in <tt>.zwc</tt>, this extension is automatically
appended. Files containing multiple compiled functions are called ‘digest’
files, and are intended to be used as elements of the <tt>FPATH</tt>/<tt>fpath</tt>
special array.
</p>
<p>The second form, with the <tt>-c</tt> or <tt>-a</tt> options, writes the compiled
definitions for all the named functions into <var>file</var>. For <tt>-c</tt>, the
names must be functions currently defined in the shell, not those marked
for autoloading. Undefined functions that are marked for autoloading
may be written by using the <tt>-a</tt> option, in which case the <tt>fpath</tt>
is searched and the contents of the definition files for those
functions, if found, are compiled into <var>file</var>. If both <tt>-c</tt> and
<tt>-a</tt> are given, names of both defined functions and functions marked
for autoloading may be given. In either case, the functions in files
written with the <tt>-c</tt> or <tt>-a</tt> option will be autoloaded as if the
<tt>KSH_AUTOLOAD</tt> option were unset.
</p>
<p>The reason for handling loaded and not-yet-loaded functions with
different options is that some definition files for autoloading define
multiple functions, including the function with the same name as the
file, and, at the end, call that function. In such cases the output of
‘<tt>zcompile -c</tt>’ does not include the additional functions defined in
the file, and any other initialization code in the file is lost. Using
‘<tt>zcompile -a</tt>’ captures all this extra information.
</p>
<p>If the <tt>-m</tt> option is combined with <tt>-c</tt> or <tt>-a</tt>,
the <var>name</var>s are used as patterns and all functions whose names
match one of these patterns will be written. If no <var>name</var> is given,
the definitions of all functions currently defined or marked as
autoloaded will be written.
</p>
<p>Note the second form cannot be used for compiling functions that
include redirections as part of the definition rather than within
the body of the function; for example
</p>
<div class="example">
<pre class="example">fn1() { { ... } >~/logfile }
</pre></div>
<p>can be compiled but
</p>
<div class="example">
<pre class="example">fn1() { ... } >~/logfile
</pre></div>
<p>cannot. It is possible to use the first form of <tt>zcompile</tt> to compile
autoloadable functions that include the full function definition instead
of just the body of the function.
</p>
<p>The third form, with the <tt>-t</tt> option, examines an existing
compiled file. Without further arguments, the names of the original
files compiled into it are listed. The first line of output shows
the version of the shell which compiled the file and how the file
will be used (i.e. by reading it directly or by mapping it into memory).
With arguments, nothing is output and the return status is set to zero if
definitions for <em>all</em> <var>name</var>s were found in the compiled
file, and non-zero if the definition for at least one <var>name</var> was not
found.
</p>
<p>Other options:
</p>
<dl compact="compact">
<dt><tt>-U</tt></dt>
<dd><p>Aliases are not expanded when compiling the <var>name</var>d files.
</p>
</dd>
<dt><tt>-R</tt></dt>
<dd><p>When the compiled file is read, its contents are copied into the
shell’s memory, rather than memory-mapped (see <tt>-M</tt>). This
happens automatically on systems that do not support memory mapping.
</p>
<p>When compiling scripts instead of autoloadable functions, it is
often desirable to use this option; otherwise the whole file, including the
code to define functions which have already been defined, will
remain mapped, consequently wasting memory.
</p>
</dd>
<dt><tt>-M</tt></dt>
<dd><p>The compiled file is mapped into the shell’s memory when read. This
is done in such a way that multiple instances of the shell running
on the same host will share this mapped file. If neither <tt>-R</tt> nor
<tt>-M</tt> is given, the <tt>zcompile</tt> builtin decides what to do based
on the size of the compiled file.
</p>
</dd>
<dt><tt>-k</tt></dt>
<dt><tt>-z</tt></dt>
<dd><p>These options are used when the compiled file contains functions which
are to be autoloaded. If <tt>-z</tt> is given, the
function will be autoloaded as if the <tt>KSH_AUTOLOAD</tt> option is
<em>not</em> set, even if it is set at the time the compiled file is
read, while if the <tt>-k</tt> is given, the function will be loaded as if
<tt>KSH_AUTOLOAD</tt> <em>is</em> set. These options also take precedence over
any <tt>-k</tt> or <tt>-z</tt> options specified to the <tt>autoload</tt> builtin. If
neither of these options is given, the function will be loaded as
determined by the setting of the <tt>KSH_AUTOLOAD</tt> option at the time
the compiled file is read.
</p>
<p>These options may also appear as many times as necessary between the listed
<var>name</var>s to specify the loading style of all following functions, up to
the next <tt>-k</tt> or <tt>-z</tt>.
</p>
</dd>
</dl>
<p>The created file always contains two versions of the compiled
format, one for big-endian machines and one for small-endian
machines. The upshot of this is that the compiled file is machine
independent and if it is read or mapped, only one half of the file
is actually used (and mapped).
</p>
</dd>
<dt><tt>zformat</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fzutil-Module">The zsh/zutil Module</a>.
</p>
</dd>
<dt><tt>zftp</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fzftp-Module">The zsh/zftp Module</a>.
</p>
</dd>
<dt><tt>zle</tt></dt>
<dd><p>See <a href="Zsh-Line-Editor.html#Zle-Builtins">Zle Builtins</a>.
</p>
<a name="index-zmodload"></a>
<a name="index-modules_002c-loading"></a>
<a name="index-loading-modules"></a>
</dd>
<dt><tt>zmodload</tt> [ <tt>-dL</tt> ] [ <tt>-s</tt> ] [ ... ]</dt>
<dt><tt>zmodload -F</tt> [ <tt>-alLme</tt> <tt>-P</tt> <var>param</var> ] <var>module</var> [ [<tt>+-</tt>]<var>feature</var> ... ]</dt>
<dt><tt>zmodload -e</tt> [ <tt>-A</tt> ] [ ... ]</dt>
<dt><tt>zmodload</tt> [ <tt>-a</tt> [ <tt>-bcpf</tt> [ <tt>-I</tt> ] ] ] [ <tt>-iL</tt> ] ...</dt>
<dt><tt>zmodload</tt> <tt>-u</tt> [ <tt>-abcdpf</tt> [ <tt>-I</tt> ] ] [ <tt>-iL</tt> ] ...</dt>
<dt><tt>zmodload</tt> <tt>-A</tt> [ <tt>-L</tt> ] [ <var>modalias</var>[<tt>=</tt><var>module</var>] ... ]</dt>
<dt><tt>zmodload</tt> <tt>-R</tt> <var>modalias</var> ...</dt>
<dd><p>Performs operations relating to zsh’s loadable modules.
Loading of modules while the shell is running (‘dynamical loading’) is not
available on all operating systems, or on all installations on a particular
operating system, although the <tt>zmodload</tt> command itself is always
available and can be used to manipulate modules built into versions of the
shell executable without dynamical loading.
</p>
<p>Without arguments the names of all currently loaded binary modules are
printed. The <tt>-L</tt> option causes this list to be in the form of a
series of <tt>zmodload</tt> commands. Forms with arguments are:
</p>
<dl compact="compact">
<dt><tt>zmodload</tt> [ <tt>-is</tt> ] <var>name</var> ...</dt>
<dt><tt>zmodload</tt> <tt>-u</tt> [ <tt>-i</tt> ] <var>name</var> ...</dt>
<dd><p>In the simplest case, <tt>zmodload</tt> loads a binary module. The module must
be in a file with a name consisting of the specified <var>name</var> followed by
a standard suffix, usually ‘<tt>.so</tt>’ (‘<tt>.sl</tt>’ on HPUX).
If the module to be loaded is already loaded the duplicate module is
ignored. If <tt>zmodload</tt> detects an inconsistency, such as an
invalid module name or circular dependency list, the current code block is
aborted. If it is available, the module is loaded if necessary, while if it
is not available, non-zero status is silently returned. The option
<tt>-i</tt> is accepted for compatibility but has no effect.
</p>
<p>The <var>name</var>d module is searched for in the same way a command is, using
<tt>$module_path</tt> instead of <tt>$path</tt>. However, the path search is
performed even when the module name contains a ‘<tt>/</tt>’, which it usually does.
There is no way to prevent the path search.
</p>
<p>If the module supports features (see below), <tt>zmodload</tt> tries to
enable all features when loading a module. If the module was successfully
loaded but not all features could be enabled, <tt>zmodload</tt> returns status 2.
</p>
<p>If the option <tt>-s</tt> is given, no error is printed if the module was not
available (though other errors indicating a problem with the module are
printed). The return status indicates if the module was loaded. This
is appropriate if the caller considers the module optional.
</p>
<p>With <tt>-u</tt>, <tt>zmodload</tt> unloads modules. The same <var>name</var>
must be given that was given when the module was loaded, but it is not
necessary for the module to exist in the file system.
The <tt>-i</tt> option suppresses the error if the module is already
unloaded (or was never loaded).
</p>
<p>Each module has a boot and a cleanup function. The module
will not be loaded if its boot function fails. Similarly a module
can only be unloaded if its cleanup function runs successfully.
</p>
</dd>
<dt><tt>zmodload -F</tt> [ <tt>-almLe</tt> <tt>-P</tt> <var>param</var> ] <var>module</var> [ [<tt>+-</tt>]<var>feature</var> ... ]</dt>
<dd><p><tt>zmodload -F</tt> allows more selective control over the features provided
by modules. With no options apart from <tt>-F</tt>, the module named
<var>module</var> is loaded, if it was not already loaded, and the list of
<var>feature</var>s is set to the required state. If no
<var>feature</var>s are specified, the module is loaded, if it was not already
loaded, but the state of features is unchanged. Each feature
may be preceded by a <tt>+</tt> to turn the feature on, or <tt>-</tt> to turn it
off; the <tt>+</tt> is assumed if neither character is present.
Any feature not explicitly mentioned is left in its current state;
if the module was not previously loaded this means any such features will
remain disabled. The return status is zero if all features were
set, 1 if the module failed to load, and 2 if some features could
not be set (for example, a parameter couldn’t be added because there
was a different parameter of the same name) but the module was loaded.
</p>
<p>The standard features are builtins, conditions, parameters and math
functions; these are indicated by the prefix ‘<tt>b:</tt>’, ‘<tt>c:</tt>’
(‘<tt>C:</tt>’ for an infix condition), ‘<tt>p:</tt>’ and ‘<tt>f:</tt>’, respectively,
followed by the name that the corresponding feature would have in the
shell. For example, ‘<tt>b:strftime</tt>’ indicates a builtin named
<tt>strftime</tt> and <tt>p:EPOCHSECONDS</tt> indicates a parameter named
<tt>EPOCHSECONDS</tt>. The module may provide other (‘abstract’) features of
its own as indicated by its documentation; these have no prefix.
</p>
<p>With <tt>-l</tt> or <tt>-L</tt>, features provided by the module are listed. With
<tt>-l</tt> alone, a list of features together with their states is shown, one
feature per line. With <tt>-L</tt> alone, a <tt>zmodload -F</tt> command that would
cause enabled features of the module to be turned on is shown. With
<tt>-lL</tt>, a <tt>zmodload -F</tt> command that would cause all the features to be
set to their current state is shown. If one of these combinations is given
with the option <tt>-P</tt> <var>param</var> then the parameter <var>param</var> is set to an
array of features, either features together with their state or (if
<tt>-L</tt> alone is given) enabled features.
</p>
<p>With the option <tt>-L</tt> the module name may be omitted; then a list
of all enabled features for all modules providing features is printed
in the form of <tt>zmodload -F</tt> commands. If <tt>-l</tt> is also given,
the state of both enabled and disabled features is output in that form.
</p>
<p>A set of features may be provided together with <tt>-l</tt> or <tt>-L</tt> and a
module name; in that case only the state of those features is
considered. Each feature may be preceded by <tt>+</tt> or <tt>-</tt> but the
character has no effect. If no set of features is provided, all
features are considered.
</p>
<p>With <tt>-e</tt>, the command first tests that the module is loaded;
if it is not, status 1 is returned. If the module is loaded,
the list of features given as an argument is examined. Any feature
given with no prefix is simply tested to see if the module provides it;
any feature given with a prefix <tt>+</tt> or <tt>-</tt> is tested to
see if is provided and in the given state. If the tests on all features
in the list succeed, status 0 is returned, else status 1.
</p>
<p>With <tt>-m</tt>, each entry in the given list of features is taken
as a pattern to be matched against the list of features provided
by the module. An initial <tt>+</tt> or <tt>-</tt> must be given explicitly.
This may not be combined with the <tt>-a</tt> option as autoloads must
be specified explicitly.
</p>
<p>With <tt>-a</tt>, the given list of features is marked for autoload from
the specified module, which may not yet be loaded. An optional <tt>+</tt>
may appear before the feature name. If the feature is prefixed with
<tt>-</tt>, any existing autoload is removed. The options <tt>-l</tt> and <tt>-L</tt>
may be used to list autoloads. Autoloading is specific to individual
features; when the module is loaded only the requested feature is
enabled. Autoload requests are preserved if the module is
subsequently unloaded until an explicit ‘<tt>zmodload -Fa</tt> <var>module</var>
<tt>-</tt><var>feature</var>’ is issued. It is not an error to request an autoload
for a feature of a module that is already loaded.
</p>
<p>When the module is loaded each autoload is checked against the features
actually provided by the module; if the feature is not provided the
autoload request is deleted. A warning message is output; if the
module is being loaded to provide a different feature, and that autoload
is successful, there is no effect on the status of the current command.
If the module is already loaded at the time when <tt>zmodload -Fa</tt> is
run, an error message is printed and status 1 returned.
</p>
<p><tt>zmodload -Fa</tt> can be used with the <tt>-l</tt>, <tt>-L</tt>, <tt>-e</tt> and
<tt>-P</tt> options for listing and testing the existence of autoloadable
features. In this case <tt>-l</tt> is ignored if <tt>-L</tt> is specified.
<tt>zmodload -FaL</tt> with no module name lists autoloads for all modules.
</p>
<p>Note that only standard features as described above can be autoloaded;
other features require the module to be loaded before enabling.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-d</tt> [ <tt>-L</tt> ] [ <var>name</var> ]</dt>
<dt><tt>zmodload</tt> <tt>-d</tt> <var>name</var> <var>dep</var> ...</dt>
<dt><tt>zmodload</tt> <tt>-ud</tt> <var>name</var> [ <var>dep</var> ... ]</dt>
<dd><p>The <tt>-d</tt> option can be used to specify module dependencies. The modules
named in the second and subsequent arguments will be loaded before the
module named in the first argument.
</p>
<p>With <tt>-d</tt> and one argument, all dependencies for that module are listed.
With <tt>-d</tt> and no arguments, all module dependencies are listed. This
listing is by default in a Makefile-like format. The <tt>-L</tt> option
changes this format to a list of <tt>zmodload -d</tt> commands.
</p>
<p>If <tt>-d</tt> and <tt>-u</tt> are both used, dependencies are removed. If only one
argument is given, all dependencies for that module are removed.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-ab</tt> [ <tt>-L</tt> ]</dt>
<dt><tt>zmodload</tt> <tt>-ab</tt> [ <tt>-i</tt> ] <var>name</var> [ <var>builtin</var> ... ]</dt>
<dt><tt>zmodload</tt> <tt>-ub</tt> [ <tt>-i</tt> ] <var>builtin</var> ...</dt>
<dd><p>The <tt>-ab</tt> option defines autoloaded builtins. It defines the specified
<var>builtin</var>s. When any of those builtins is called, the module specified
in the first argument is loaded and all its features are enabled (for
selective control of features use ‘<tt>zmodload -F -a</tt>’ as described
above). If only the <var>name</var> is given, one builtin is defined, with
the same name as the module. <tt>-i</tt> suppresses the error if the builtin
is already defined or autoloaded, but not if another builtin of the
same name is already defined.
</p>
<p>With <tt>-ab</tt> and no arguments, all autoloaded builtins are listed, with the
module name (if different) shown in parentheses after the builtin name.
The <tt>-L</tt> option changes this format to a list of <tt>zmodload -a</tt>
commands.
</p>
<p>If <tt>-b</tt> is used together with the <tt>-u</tt> option, it removes builtins
previously defined with <tt>-ab</tt>. This is only possible if the builtin is
not yet loaded. <tt>-i</tt> suppresses the error if the builtin is already
removed (or never existed).
</p>
<p>Autoload requests are retained if the module is subsequently unloaded
until an explicit ‘<tt>zmodload -ub</tt> <var>builtin</var>’ is issued.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-ac</tt> [ <tt>-IL</tt> ]</dt>
<dt><tt>zmodload</tt> <tt>-ac</tt> [ <tt>-iI</tt> ] <var>name</var> [ <var>cond</var> ... ]</dt>
<dt><tt>zmodload</tt> <tt>-uc</tt> [ <tt>-iI</tt> ] <var>cond</var> ...</dt>
<dd><p>The <tt>-ac</tt> option is used to define autoloaded condition codes. The
<var>cond</var> strings give the names of the conditions defined by the
module. The optional <tt>-I</tt> option is used to define infix condition
names. Without this option prefix condition names are defined.
</p>
<p>If given no condition names, all defined names are listed (as a series of
<tt>zmodload</tt> commands if the <tt>-L</tt> option is given).
</p>
<p>The <tt>-uc</tt> option removes definitions for autoloaded conditions.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-ap</tt> [ <tt>-L</tt> ]</dt>
<dt><tt>zmodload</tt> <tt>-ap</tt> [ <tt>-i</tt> ] <var>name</var> [ <var>parameter</var> ... ]</dt>
<dt><tt>zmodload</tt> <tt>-up</tt> [ <tt>-i</tt> ] <var>parameter</var> ...</dt>
<dd><p>The <tt>-p</tt> option is like the <tt>-b</tt> and <tt>-c</tt> options, but makes
<tt>zmodload</tt> work on autoloaded parameters instead.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-af</tt> [ <tt>-L</tt> ]</dt>
<dt><tt>zmodload</tt> <tt>-af</tt> [ <tt>-i</tt> ] <var>name</var> [ <var>function</var> ... ]</dt>
<dt><tt>zmodload</tt> <tt>-uf</tt> [ <tt>-i</tt> ] <var>function</var> ...</dt>
<dd><p>The <tt>-f</tt> option is like the <tt>-b</tt>, <tt>-p</tt>, and <tt>-c</tt> options, but
makes <tt>zmodload</tt> work on autoloaded math functions instead.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-a</tt> [ <tt>-L</tt> ]</dt>
<dt><tt>zmodload</tt> <tt>-a</tt> [ <tt>-i</tt> ] <var>name</var> [ <var>builtin</var> ... ]</dt>
<dt><tt>zmodload</tt> <tt>-ua</tt> [ <tt>-i</tt> ] <var>builtin</var> ...</dt>
<dd><p>Equivalent to <tt>-ab</tt> and <tt>-ub</tt>.
</p>
</dd>
<dt><tt>zmodload -e</tt> [ <tt>-A</tt> ] [ <var>string</var> ... ]</dt>
<dd><p>The <tt>-e</tt> option without arguments lists all loaded modules; if the <tt>-A</tt>
option is also given, module aliases corresponding to loaded modules are
also shown. If arguments are provided, nothing is printed;
the return status is set to zero if all <var>string</var>s given as arguments
are names of loaded modules and to one if at least on <var>string</var> is not
the name of a loaded module. This can be used to test for the
availability of things implemented by modules. In this case, any
aliases are automatically resolved and the <tt>-A</tt> flag is not used.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-A</tt> [ <tt>-L</tt> ] [ <var>modalias</var>[<tt>=</tt><var>module</var>] ... ]</dt>
<dd><p>For each argument, if both <var>modalias</var> and <var>module</var> are given,
define <var>modalias</var> to be an alias for the module <var>module</var>.
If the module <var>modalias</var> is ever subsequently requested, either via a
call to <tt>zmodload</tt> or implicitly, the shell will attempt to load
<var>module</var> instead. If <var>module</var> is not given, show the definition of
<var>modalias</var>. If no arguments are given, list all defined module aliases.
When listing, if the <tt>-L</tt> flag was also given, list the definition as a
<tt>zmodload</tt> command to recreate the alias.
</p>
<p>The existence of aliases for modules is completely independent of whether
the name resolved is actually loaded as a module: while the alias exists,
loading and unloading the module under any alias has exactly the same
effect as using the resolved name, and does not affect the connection
between the alias and the resolved name which can be removed either by
<tt>zmodload -R</tt> or by redefining the alias. Chains of aliases (i.e. where
the first resolved name is itself an alias) are valid so long as these are
not circular. As the aliases take the same format as module names, they
may include path separators: in this case, there is no requirement for any
part of the path named to exist as the alias will be resolved first. For
example, ‘<tt>any/old/alias</tt>’ is always a valid alias.
</p>
<p>Dependencies added to aliased modules are actually added to the resolved
module; these remain if the alias is removed. It is valid to create an
alias whose name is one of the standard shell modules and which resolves to
a different module. However, if a module has dependencies, it
will not be possible to use the module name as an alias as the module will
already be marked as a loadable module in its own right.
</p>
<p>Apart from the above, aliases can be used in the <tt>zmodload</tt> command
anywhere module names are required. However, aliases will not be
shown in lists of loaded modules with a bare ‘<tt>zmodload</tt>’.
</p>
</dd>
<dt><tt>zmodload</tt> <tt>-R</tt> <var>modalias</var> ...</dt>
<dd><p>For each <var>modalias</var> argument that was previously defined as a module
alias via <tt>zmodload -A</tt>, delete the alias. If any was not defined, an
error is caused and the remainder of the line is ignored.
</p>
</dd>
</dl>
<p>Note that <tt>zsh</tt> makes no distinction between modules that were linked
into the shell and modules that are loaded dynamically. In both cases
this builtin command has to be used to make available the builtins and
other things defined by modules (unless the module is autoloaded on
these definitions). This is true even for systems that don’t support
dynamic loading of modules.
</p>
</dd>
<dt><tt>zparseopts</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fzutil-Module">The zsh/zutil Module</a>.
</p>
</dd>
<dt><tt>zprof</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fzprof-Module">The zsh/zprof Module</a>.
</p>
</dd>
<dt><tt>zpty</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fzpty-Module">The zsh/zpty Module</a>.
</p>
</dd>
<dt><tt>zregexparse</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fzutil-Module">The zsh/zutil Module</a>.
</p>
</dd>
<dt><tt>zsocket</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fnet_002fsocket-Module">The zsh/net/socket Module</a>.
</p>
</dd>
<dt><tt>zstyle</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fzutil-Module">The zsh/zutil Module</a>.
</p>
</dd>
<dt><tt>ztcp</tt></dt>
<dd><p>See <a href="Zsh-Modules.html#The-zsh_002fnet_002ftcp-Module">The zsh/net/tcp Module</a>.
</p>
</dd>
</dl>
<hr>
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This document was generated on <em>April 8, 2018</em> using <a href="http://www.gnu.org/software/texinfo/"><em>texi2any</em></a>.
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