ZSHBUILTINS(1) General Commands Manual ZSHBUILTINS(1)
NAME
zshbuiltins - zsh built-in commands
SHELL BUILTIN COMMANDS
Some shell builtin commands take options as described in individual en-
tries; these are often referred to in the list below as `flags' to
avoid confusion with shell options, which may also have an effect on
the behaviour of builtin commands. In this introductory section, `op-
tion' always has the meaning of an option to a command that should be
familiar to most command line users.
Typically, options are single letters preceded by a hyphen (-). Op-
tions that take an argument accept it either immediately following the
option letter or after white space, for example `print -C3 {1..9}' or
`print -C 3 {1..9}' 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 sin-
gle word, for example `print -rca -- *' and `print -r -c -a -- *' are
equivalent.
Some shell builtin commands also take options that begin with `+' in-
stead of `-'. The list below makes clear which commands these are.
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.
All builtin commands other than `echo' and precommand modifiers, even
those that have no options, can be given the argument `--' to terminate
option processing. This indicates that the following words are non-op-
tion arguments, but is otherwise ignored. This is useful in cases
where arguments to the command may begin with `-'. For historical rea-
sons, most builtin commands (including `echo') also recognize a single
`-' in a separate word for this purpose; note that this is less stan-
dard and use of `--' is recommended.
- simple command
See the section `Precommand Modifiers' in zshmisc(1).
. file [ arg ... ]
Read commands from file and execute them in the current shell
environment.
If file does not contain a slash, or if PATH_DIRS is set, the
shell looks in the components of $path to find the directory
containing file. Files in the current directory are not read
unless `.' appears somewhere in $path. If a file named
`file.zwc' is found, is newer than file, and is the compiled
form (created with the zcompile builtin) of file, then commands
are read from that file instead of file.
If any arguments arg are given, they become the positional pa-
rameters; the old positional parameters are restored when the
file is done executing. However, if no arguments are given, the
positional parameters remain those of the calling context, and
no restoring is done.
If file was not found the return status is 127; if file 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.
: [ arg ... ]
This command does nothing, although normal argument expansions
is performed which may have effects on shell parameters. A zero
exit status is returned.
alias [ {+|-}gmrsL ] [ name[=value] ... ]
For each name with a corresponding value, define an alias with
that value. A trailing space in value causes the next word to
be checked for alias expansion. If the -g flag is present, de-
fine a global alias; global aliases are expanded even if they do
not occur in command position:
% perldoc --help 2>&1 | grep 'built-in functions'
-f Search Perl built-in functions
% alias -g HG='--help 2>&1 | grep'
% perldoc HG 'built-in functions'
-f Search Perl built-in functions
If the -s flag is present, define a suffix alias: if the command
word on a command line is in the form `text.name', where text is
any non-empty string, it is replaced by the text `value
text.name'. Note that name is treated as a literal string, not
a pattern. A trailing space in value is not special in this
case. For example,
alias -s ps='gv --'
will cause the command `*.ps' to be expanded to `gv -- *.ps'.
As alias expansion is carried out earlier than globbing, the
`*.ps' will then be expanded. Suffix aliases constitute a dif-
ferent name space from other aliases (so in the above example it
is still possible to create an alias for the command ps) and the
two sets are never listed together.
For each name with no value, print the value of name, if any.
With no arguments, print all currently defined aliases other
than suffix aliases. If the -m 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 -g, -r or -s 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 `+'
instead of `-', or ending the option list with a single `+',
prevents the values of the aliases from being printed.
If the -L flag is present, then print each alias in a manner
suitable for putting in a startup script. The exit status is
nonzero if a name (with no value) is given for which no alias
has been defined.
For more on aliases, include common problems, see the section
ALIASING in zshmisc(1).
autoload [ {+|-}RTUXdkmrtWz ] [ -w ] [ name ... ]
See the section `Autoloading Functions' in zshmisc(1) for full
details. The fpath parameter will be searched to find the func-
tion definition when the function is first referenced.
If name 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 -d is given, searching for the function defaults to
$fpath. If a function is loaded by absolute path, any functions
loaded from it that are marked for autoload without an absolute
path have the load path of the parent function temporarily
prepended to $fpath.
If the option -r or -R 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 $PWD. This protects against a change to $fpath after
the call to autoload. With -r, if the function is not found, it
is silently left unresolved until execution; with -R, an error
message is printed and command processing aborted immediately
the search fails, i.e. at the autoload command rather than at
function execution..
The flag -X may be used only inside a shell function. It causes
the calling function to be marked for autoloading and then imme-
diately loaded and executed, with the current array of posi-
tional parameters as arguments. This replaces the previous def-
inition 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 di-
rectory (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
-d option to allow the function search to default to $fpath if
it is not in the given location.
The flag +X attempts to load each name as an autoloaded func-
tion, but does not execute it. The exit status is zero (suc-
cess) if the function was not previously defined and a defini-
tion for it was found. This does not replace any existing defi-
nition 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 -m flag is also given each name is treated as a pattern and
all functions already marked for autoload that match the pattern
are loaded.
With the -t flag, turn on execution tracing; with -T, 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.
With the -U flag, alias expansion is suppressed when the func-
tion is loaded.
With the -w flag, the names are taken as names of files compiled
with the zcompile builtin, and all functions defined in them are
marked for autoloading.
The flags -z and -k mark the function to be autoloaded using the
zsh or ksh style, as if the option KSH_AUTOLOAD were unset or
were set, respectively. The flags override the setting of the
option at the time the function is loaded.
Note that the autoload 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 emulate command can be
used:
emulate zsh -c 'autoload -Uz func'
arranges that when func is loaded the shell is in native zsh em-
ulation, and this emulation is also applied when func is run.
Some of the functions of autoload are also provided by functions
-u or functions -U, but autoload is a more comprehensive inter-
face.
bg [ job ... ]
job ... &
Put each specified job in the background, or the current job if
none is specified.
bindkey
See the section `Zle Builtins' in zshzle(1).
break [ n ]
Exit from an enclosing for, while, until, select or repeat loop.
If an arithmetic expression n is specified, then break n levels
instead of just one.
builtin name [ args ... ]
Executes the builtin name, with the given args.
bye Same as exit.
cap See the section `The zsh/cap Module' in zshmodules(1).
cd [ -qsLP ] [ arg ]
cd [ -qsLP ] old new
cd [ -qsLP ] {+|-}n
Change the current directory. In the first form, change the
current directory to arg, or to the value of $HOME if arg is not
specified. If arg is `-', change to the previous directory.
Otherwise, if arg begins with a slash, attempt to change to the
directory given by arg.
If arg does not begin with a slash, the behaviour depends on
whether the current directory `.' occurs in the list of directo-
ries contained in the shell parameter cdpath. If it does not,
first attempt to change to the directory arg under the current
directory, and if that fails but cdpath is set and contains at
least one element attempt to change to the directory arg under
each component of cdpath in turn until successful. If `.' oc-
curs in cdpath, then cdpath is searched strictly in order so
that `.' is only tried at the appropriate point.
The order of testing cdpath is modified if the option POSIX_CD
is set, as described in the documentation for the option.
If no directory is found, the option CDABLE_VARS is set, and a
parameter named arg 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.
The second form of cd substitutes the string new for the string
old in the name of the current directory, and tries to change to
this new directory.
The third form of cd extracts an entry from the directory stack,
and changes to that directory. An argument of the form `+n'
identifies a stack entry by counting from the left of the list
shown by the dirs command, starting with zero. An argument of
the form `-n' counts from the right. If the PUSHD_MINUS option
is set, the meanings of `+' and `-' in this context are swapped.
If the POSIX_CD option is set, this form of cd is not recognised
and will be interpreted as the first form.
If the -q (quiet) option is specified, the hook function chpwd
and the functions in the array chpwd_functions are not called.
This is useful for calls to cd that do not change the environ-
ment seen by an interactive user.
If the -s option is specified, cd refuses to change the current
directory if the given pathname contains symlinks. If the -P
option is given or the CHASE_LINKS option is set, symbolic links
are resolved to their true values. If the -L option is given
symbolic links are retained in the directory (and not resolved)
regardless of the state of the CHASE_LINKS option.
chdir Same as cd.
clone See the section `The zsh/clone Module' in zshmodules(1).
command [ -pvV ] simple command
The simple command argument is taken as an external command in-
stead of a function or builtin and is executed. If the
POSIX_BUILTINS option is set, builtins will also be executed but
certain special properties of them are suppressed. The -p flag
causes a default path to be searched instead of that in $path.
With the -v flag, command is similar to whence and with -V, it
is equivalent to whence -v.
See also the section `Precommand Modifiers' in zshmisc(1).
comparguments
See the section `The zsh/computil Module' in zshmodules(1).
compcall
See the section `The zsh/compctl Module' in zshmodules(1).
compctl
See the section `The zsh/compctl Module' in zshmodules(1).
compdescribe
See the section `The zsh/computil Module' in zshmodules(1).
compfiles
See the section `The zsh/computil Module' in zshmodules(1).
compgroups
See the section `The zsh/computil Module' in zshmodules(1).
compquote
See the section `The zsh/computil Module' in zshmodules(1).
comptags
See the section `The zsh/computil Module' in zshmodules(1).
comptry
See the section `The zsh/computil Module' in zshmodules(1).
compvalues
See the section `The zsh/computil Module' in zshmodules(1).
continue [ n ]
Resume the next iteration of the enclosing for, while, until,
select or repeat loop. If an arithmetic expression n is speci-
fied, break out of n-1 loops and resume at the nth enclosing
loop.
declare
Same as typeset.
dirs [ -c ] [ arg ... ]
dirs [ -lpv ]
With no arguments, print the contents of the directory stack.
Directories are added to this stack with the pushd command, and
removed with the cd or popd commands. If arguments are speci-
fied, load them onto the directory stack, replacing anything
that was there, and push the current directory onto the stack.
-c clear the directory stack.
-l print directory names in full instead of using of using ~
expressions (see Dynamic and Static named directories in
zshexpn(1)).
-p print directory entries one per line.
-v number the directories in the stack when printing.
disable [ -afmprs ] name ...
Temporarily disable the named 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 -a option causes disable to act on regular or global
aliases. The -s option causes disable to act on suffix aliases.
The -f option causes disable to act on shell functions. The -r
options causes disable to act on reserved words. Without argu-
ments all disabled hash table elements from the corresponding
hash table are printed. With the -m 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 dis-
abled. Disabled objects can be enabled with the enable command.
With the option -p, name ... refer to elements of the shell's
pattern syntax as described in the section `Filename Genera-
tion'. Certain elements can be disabled separately, as given
below.
Note that patterns not allowed by the current settings for the
options EXTENDED_GLOB, KSH_GLOB and SH_GLOB are never enabled,
regardless of the setting here. For example, if EXTENDED_GLOB
is not active, the pattern ^ is ineffective even if `disable -p
"^"' has not been issued. The list below indicates any option
settings that restrict the use of the pattern. It should be
noted that setting SH_GLOB has a wider effect than merely dis-
abling patterns as certain expressions, in particular those in-
volving parentheses, are parsed differently.
The following patterns may be disabled; all the strings need
quoting on the command line to prevent them from being inter-
preted immediately as patterns and the patterns are shown below
in single quotes as a reminder.
'?' The pattern character ? wherever it occurs, including
when preceding a parenthesis with KSH_GLOB.
'*' The pattern character * wherever it occurs, including re-
cursive globbing and when preceding a parenthesis with
KSH_GLOB.
'[' Character classes.
'<' (NO_SH_GLOB)
Numeric ranges.
'|' (NO_SH_GLOB)
Alternation in grouped patterns, case statements, or
KSH_GLOB parenthesised expressions.
'(' (NO_SH_GLOB)
Grouping using single parentheses. Disabling this does
not disable the use of parentheses for KSH_GLOB where
they are introduced by a special character, nor for glob
qualifiers (use `setopt NO_BARE_GLOB_QUAL' to disable
glob qualifiers that use parentheses only).
'~' (EXTENDED_GLOB)
Exclusion in the form A~B.
'^' (EXTENDED_GLOB)
Exclusion in the form A^B.
'#' (EXTENDED_GLOB)
The pattern character # wherever it occurs, both for rep-
etition of a previous pattern and for indicating globbing
flags.
'?(' (KSH_GLOB)
The grouping form ?(...). Note this is also disabled if
'?' is disabled.
'*(' (KSH_GLOB)
The grouping form *(...). Note this is also disabled if
'*' is disabled.
'+(' (KSH_GLOB)
The grouping form +(...).
'!(' (KSH_GLOB)
The grouping form !(...).
'@(' (KSH_GLOB)
The grouping form @(...).
disown [ job ... ]
job ... &|
job ... &!
Remove the specified jobs 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
job is specified, disown the current job.
If the jobs are currently stopped and the AUTO_CONTINUE 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 jobs will automatically be
made running, independent of the setting of the AUTO_CONTINUE
option.
echo [ -neE ] [ arg ... ]
Write each arg on the standard output, with a space separating
each one. If the -n flag is not present, print a newline at the
end. echo recognizes the following escape sequences:
\a bell character
\b backspace
\c suppress subsequent characters and final newline
\e escape
\f form feed
\n linefeed (newline)
\r carriage return
\t horizontal tab
\v vertical tab
\\ backslash
\0NNN character code in octal
\xNN character code in hexadecimal
\uNNNN unicode character code in hexadecimal
\UNNNNNNNN
unicode character code in hexadecimal
The -E flag, or the BSD_ECHO option, can be used to disable
these escape sequences. In the latter case, -e flag can be used
to enable them.
Note that for standards compliance a double dash does not termi-
nate option processing; instead, it is printed directly. How-
ever, a single dash does terminate option processing, so the
first dash, possibly following options, is not printed, but ev-
erything following it is printed as an argument. The single
dash behaviour is different from other shells. For a more por-
table way of printing text, see printf, and for a more control-
lable way of printing text within zsh, see print.
echotc See the section `The zsh/termcap Module' in zshmodules(1).
echoti See the section `The zsh/terminfo Module' in zshmodules(1).
emulate [ -lLR ] [ {zsh|sh|ksh|csh} [ flags ... ] ]
Without any argument print current emulation mode.
With single argument set up zsh options to emulate the specified
shell as much as possible. csh will never be fully emulated.
If the argument is not one of the shells listed above, zsh 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 the section COMPATIBIL-
ITY in zsh(1) . In addition to setting shell options, the com-
mand also restores the pristine state of pattern enables, as if
all patterns had been enabled using enable -p.
If the emulate command occurs inside a function that has been
marked for execution tracing with functions -t then the xtrace
option will be turned on regardless of emulation mode or other
options. Note that code executed inside the function by the .,
source, or eval commands is not considered to be running di-
rectly from the function, hence does not provoke this behaviour.
If the -R 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 en-
vironment; otherwise, only those options likely to cause porta-
bility problems in scripts and functions are altered. If the -L
switch is given, the options LOCAL_OPTIONS, LOCAL_PATTERNS and
LOCAL_TRAPS will be set as well, causing the effects of the emu-
late command and any setopt, disable -p or enable -p, and trap
commands to be local to the immediately surrounding shell func-
tion, if any; normally these options are turned off in all emu-
lation modes except ksh. The -L switch is mutually exclusive
with the use of -c in flags.
If there is a single argument and the -l switch is given, the
options that would be set or unset (the latter indicated with
the prefix `no') are listed. -l can be combined with -L or -R
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.
The flags may be any of the invocation-time flags described in
the section INVOCATION in zsh(1), except that `-o EMACS' and `-o
VI' may not be used. Flags such as `+r'/`+o RESTRICTED' may be
prohibited in some circumstances.
If -c arg appears in flags, arg 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 be-
fore emulate returns. The -R switch may precede the name of the
shell to emulate; note this has a meaning distinct from includ-
ing -R in flags.
Use of -c enables `sticky' emulation mode for functions defined
within the evaluated expression: the emulation mode is associ-
ated thereafter with the function so that whenever the function
is executed the emulation (respecting the -R 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 `emulate shell -c' 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 LOCAL_OPTIONS 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.
For example:
emulate sh -c 'fni() { setopt cshnullglob; }
fno() { fni; }'
fno
The two functions fni and fno are defined with sticky sh emula-
tion. fno is then executed, causing options associated with em-
ulations to be set to their values in sh. fno then calls fni;
because fni is also marked for sticky sh emulation, no option
changes take place on entry to or exit from it. Hence the op-
tion cshnullglob, turned off by sh emulation, will be turned on
within fni and remain on return to fno. On exit from fno, the
emulation mode and all options will be restored to the state
they were in before entry to the temporary emulation.
The documentation above is typically sufficient for the intended
purpose of executing code designed for other shells in a suit-
able environment. More detailed rules follow.
1. The sticky emulation environment provided by `emulate
shell -c' 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 exam-
ple, the sticky emulation is inherited by subfunctions
defined within functions with sticky emulation.
2. 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.
3. No special handling is provided for functions marked for
autoload nor for functions present in wordcode created by
the zcompile command.
4. The presence or absence of the -R switch to emulate cor-
responds to different sticky emulation modes, so for ex-
ample `emulate sh -c', `emulate -R sh -c' and `emulate
csh -c' are treated as three distinct sticky emulations.
5. Difference in shell options supplied in addition to the
basic emulation also mean the sticky emulations are dif-
ferent, so for example `emulate zsh -c' and `emulate zsh
-o cbases -c' are treated as distinct sticky emulations.
enable [ -afmprs ] name ...
Enable the named hash table elements, presumably disabled ear-
lier with disable. The default is to enable builtin commands.
The -a option causes enable to act on regular or global aliases.
The -s option causes enable to act on suffix aliases. The -f
option causes enable to act on shell functions. The -r option
causes enable to act on reserved words. Without arguments all
enabled hash table elements from the corresponding hash table
are printed. With the -m flag the arguments are taken as pat-
terns (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 disable builtin com-
mand.
enable -p reenables patterns disabled with disable -p. Note
that it does not override globbing options; for example, `enable
-p "~"' does not cause the pattern character ~ to be active un-
less the EXTENDED_GLOB option is also set. To enable all possi-
ble patterns (so that they may be individually disabled with
disable -p), use `setopt EXTENDED_GLOB KSH_GLOB NO_SH_GLOB'.
eval [ arg ... ]
Read the arguments as input to the shell and execute the result-
ing 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 args or they contain no commands (i.e.
are an empty string or whitespace) the return status is zero.
exec [ -cl ] [ -a argv0 ] [ command [ arg ... ] ]
Replace the current shell with command rather than forking. If
command is a shell builtin command or a shell function, the
shell executes it, and exits when the command is complete.
With -c clear the environment; with -l prepend - to the argv[0]
string of the command executed (to simulate a login shell); with
-a argv0 set the argv[0] string of the command executed. See
the section `Precommand Modifiers' in zshmisc(1).
If the option POSIX_BUILTINS is set, command is never inter-
preted as a shell builtin command or shell function. This means
further precommand modifiers such as builtin and noglob are also
not interpreted within the shell. Hence command is always found
by searching the command path.
If command is omitted but any redirections are specified, then
the redirections will take effect in the current shell.
exit [ n ]
Exit the shell with the exit status specified by an arithmetic
expression n; if none is specified, use the exit status from the
last command executed. An EOF condition will also cause the
shell to exit, unless the IGNORE_EOF option is set.
See notes at the end of the section JOBS in zshmisc(1) for some
possibly unexpected interactions of the exit command with jobs.
export [ name[=value] ... ]
The specified names are marked for automatic export to the envi-
ronment of subsequently executed commands. Equivalent to type-
set -gx. If a parameter specified does not already exist, it is
created in the global scope.
false [ arg ... ]
Do nothing and return an exit status of 1.
fc [ -e ename ] [ -s ] [ -LI ] [ -m match ] [ old=new ... ] [ first [
last ] ]
fc -l [ -LI ] [ -nrdfEiD ] [ -t timefmt ] [ -m match ]
[ old=new ... ] [ first [ last ] ]
fc -p [ -a ] [ filename [ histsize [ savehistsize ] ] ]
fc -P
fc -ARWI [ filename ]
The fc 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 automati-
cally, but it can be forced by setting the interactive option
when starting the shell.
The first two forms of this command select a range of events
from first to last from the history list. The arguments first
and last may be specified as a number or as a string. A nega-
tive 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 old=new, if any, are then
performed on the text of the events.
The range of events selected by numbers can be narrowed further
by the following flags.
-I restricts to only internal events (not from $HISTFILE)
-L restricts to only local events (not from other shells,
see SHARE_HISTORY in zshoptions(1) -- note that $HISTFILE
is considered local when read at startup)
-m takes the first argument as a pattern (which should be
quoted) and only the history events matching this pattern
are considered
If first is not specified, it will be set to -1 (the most recent
event), or to -16 if the -l flag is given. If last is not spec-
ified, it will be set to first, or to -1 if the -l flag is
given. However, if the current event has added entries to the
history with `print -s' or `fc -R', then the default last for -l
includes all new history entries since the current event began.
When the -l flag is given, the resulting events are listed on
standard output. Otherwise the editor program specified by -e
ename is invoked on a file containing these history events. If
-e is not given, the value of the parameter FCEDIT is used; if
that is not set the value of the parameter EDITOR is used; if
that is not set a builtin default, usually `vi' is used. If
ename is `-', no editor is invoked. When editing is complete,
the edited command is executed.
The flag `-s' is equivalent to `-e -'. The flag -r reverses the
order of the events and the flag -n suppresses event numbers
when listing.
Also when listing,
-d prints timestamps for each event
-f prints full time-date stamps in the US `MM/DD/YY hh:mm'
format
-E prints full time-date stamps in the European `dd.mm.yyyy
hh:mm' format
-i prints full time-date stamps in ISO8601 `yyyy-mm-dd
hh:mm' format
-t fmt prints time and date stamps in the given format; fmt is
formatted with the strftime function with the zsh exten-
sions described for the %D{string} prompt format in the
section EXPANSION OF PROMPT SEQUENCES in zshmisc(1). The
resulting formatted string must be no more than 256 char-
acters or will not be printed
-D prints elapsed times; may be combined with one of the op-
tions above
`fc -p' pushes the current history list onto a stack and
switches to a new history list. If the -a option is also speci-
fied, this history list will be automatically popped when the
current function scope is exited, which is a much better solu-
tion than creating a trap function to call `fc -P' manually. If
no arguments are specified, the history list is left empty,
$HISTFILE is unset, and $HISTSIZE & $SAVEHIST are set to their
default values. If one argument is given, $HISTFILE is set to
that filename, $HISTSIZE & $SAVEHIST are left unchanged, and the
history file is read in (if it exists) to initialize the new
list. If a second argument is specified, $HISTSIZE & $SAVEHIST
are instead set to the single specified numeric value. Finally,
if a third argument is specified, $SAVEHIST is set to a separate
value from $HISTSIZE. You are free to change these environment
values for the new history list however you desire in order to
manipulate the new history list.
`fc -P' pops the history list back to an older list saved by `fc
-p'. The current list is saved to its $HISTFILE before it is
destroyed (assuming that $HISTFILE and $SAVEHIST are set appro-
priately, of course). The values of $HISTFILE, $HISTSIZE, and
$SAVEHIST are restored to the values they had when `fc -p' was
called. Note that this restoration can conflict with making
these variables "local", so your best bet is to avoid local dec-
larations for these variables in functions that use `fc -p'.
The one other guaranteed-safe combination is declaring these
variables to be local at the top of your function and using the
automatic option (-a) with `fc -p'. 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.
`fc -R' reads the history from the given file, `fc -W' writes
the history out to the given file, and `fc -A' appends the his-
tory out to the given file. If no filename is specified, the
$HISTFILE is assumed. If the -I option is added to -R, only
those events that are not already contained within the internal
history list are added. If the -I option is added to -A or -W,
only those events that are new since last incremental ap-
pend/write to the history file are appended/written. In any
case, the created file will have no more than $SAVEHIST entries.
fg [ job ... ]
job ...
Bring each specified job in turn to the foreground. If no job
is specified, resume the current job.
float [ {+|-}Hghlprtux ] [ {+|-}EFLRZ [ n ] ] [ name[=value] ... ]
Equivalent to typeset -E, except that options irrelevant to
floating point numbers are not permitted.
functions [ {+|-}UkmtTuWz ] [ -x num ] [ name ... ]
functions -c oldfn newfn
functions -M [-s] mathfn [ min [ max [ shellfn ] ] ]
functions -M [ -m pattern ... ]
functions +M [ -m ] mathfn ...
Equivalent to typeset -f, with the exception of the -c, -x, -M
and -W options. For functions -u and functions -U, see au-
toload, which provides additional options. For functions -t and
functions -T, see typeset -f.
The -x option indicates that any functions output will have each
leading tab for indentation, added by the shell to show syntac-
tic structure, expanded to the given number num of spaces. num
can also be 0 to suppress all indentation.
The -W option turns on the option WARN_NESTED_VAR for the named
function or functions only. The option is turned off at the
start of nested functions (apart from anonoymous functions) un-
less the called function also has the -W attribute.
The -c option causes oldfn to be copied to newfn. The copy is
efficiently handled internally by reference counting. If oldfn
was marked for autoload it is first loaded and if this fails the
copy fails. Either function may subsequently be redefined with-
out affecting the other. A typical idiom is that oldfn is the
name of a library shell function which is then redefined to call
newfn, thereby installing a modified version of the function.
The -M and +M flags
Use of the -M option may not be combined with any of the options
handled by typeset -f.
functions -M mathfn defines mathfn as the name of a mathematical
function recognised in all forms of arithmetical expressions;
see the section `Arithmetic Evaluation' in zshmisc(1). By de-
fault mathfn may take any number of comma-separated arguments.
If min is given, it must have exactly min args; if min and max
are both given, it must have at least min and at most max args.
max may be -1 to indicate that there is no upper limit.
By default the function is implemented by a shell function of
the same name; if shellfn is specified it gives the name of the
corresponding shell function while mathfn remains the name used
in arithmetical expressions. The name of the function in $0 is
mathfn (not shellfn as would usually be the case), provided the
option FUNCTION_ARGZERO is in effect. The positional parameters
in the shell function correspond to the arguments of the mathe-
matical function call.
The result of the last arithmetical expression evaluated inside
the shell function gives the result of the mathematical func-
tion. This is not limited to arithmetic substitutions of the
form $((...)), but also includes arithmetical expressions evalu-
ated in any other way, including by the let builtin, by ((...))
statements, and even by the return builtin and by array sub-
scripts. Therefore, care must be taken not to use syntactical
constructs that perform arithmetic evaluation after evaluating
what is to be the result of the function. For example:
# WRONG
zmath_cube() {
(( $1 * $1 * $1 ))
return 0
}
functions -M cube 1 1 zmath_cube
print $(( cube(3) ))
This will print `0' because of the return.
Commenting the return out would lead to a different problem: the
((...)) statement would become the last statement in the func-
tion, so the return status ($?) of the function would be
non-zero (indicating failure) whenever the arithmetic result of
the function would happen to be zero (numerically):
# WRONG
zmath_cube() {
(( $1 * $1 * $1 ))
}
functions -M cube 1 1 zmath_cube
print $(( cube(0) ))
Instead, the true builtin can be used:
# RIGHT
zmath_cube() {
(( $1 * $1 * $1 ))
true
}
functions -M cube 1 1 zmath_cube
print $(( cube(3) ))
If the additional option -s is given to functions -M, the argu-
ment to the function is a single string: anything between the
opening and matching closing parenthesis is passed to the func-
tion as a single argument, even if it includes commas or white
space. The minimum and maximum argument specifiers must there-
fore be 1 if given. An empty argument list is passed as a
zero-length string. Thus, the following string function takes a
single argument, including the commas, and prints 11:
stringfn() { (( $#1 )); true }
functions -Ms stringfn
print $(( stringfn(foo,bar,rod) ))
functions -M with no arguments lists all such user-defined func-
tions in the same form as a definition. With the additional op-
tion -m and a list of arguments, all functions whose mathfn
matches one of the pattern arguments are listed.
function +M removes the list of mathematical functions; with the
additional option -m the arguments are treated as patterns and
all functions whose mathfn matches the pattern are removed.
Note that the shell function implementing the behaviour is not
removed (regardless of whether its name coincides with mathfn).
getcap See the section `The zsh/cap Module' in zshmodules(1).
getln [ -AclneE ] name ...
Read the top value from the buffer stack and put it in the shell
parameter name. Equivalent to read -zr.
getopts optstring name [ arg ... ]
Checks the args for legal options. If the args are omitted, use
the positional parameters. A valid option argument begins with
a `+' or a `-'. An argument not beginning with a `+' or a `-',
or the argument `--', ends the options. Note that a single `-'
is not considered a valid option argument. optstring contains
the letters that getopts recognizes. If a letter is followed by
a `:', that option requires an argument. The options can be
separated from the argument by blanks.
Each time it is invoked, getopts places the option letter it
finds in the shell parameter name, prepended with a `+' when arg
begins with a `+'. The index of the next arg is stored in
OPTIND. The option argument, if any, is stored in OPTARG.
The first option to be examined may be changed by explicitly as-
signing to OPTIND. OPTIND has an initial value of 1, and is
normally set to 1 upon entry to a shell function and restored
upon exit. (The POSIX_BUILTINS option disables this, and also
changes the way the value is calculated to match other shells.)
OPTARG is not reset and retains its value from the most recent
call to getopts. If either of OPTIND or OPTARG is explicitly
unset, it remains unset, and the index or option argument is not
stored. The option itself is still stored in name in this case.
A leading `:' in optstring causes getopts to store the letter of
any invalid option in OPTARG, and to set name to `?' for an un-
known option and to `:' when a required argument is missing.
Otherwise, getopts sets name to `?' and prints an error message
when an option is invalid. The exit status is nonzero when
there are no more options.
hash [ -Ldfmrv ] [ name[=value] ] ...
hash 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 PATH (for the com-
mand 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 -d option; without the option
the command hash table is used, and with the option the named
directory hash table is used.
A command name starting with a / is never hashed, whether by ex-
plicit use of the hash command or otherwise. Such a command is
always found by direct look up in the file system.
Given no arguments, and neither the -r or -f options, the se-
lected hash table will be listed in full.
The -r option causes the selected hash table to be emptied. It
will be subsequently rebuilt in the normal fashion. The -f op-
tion causes the selected hash table to be fully rebuilt immedi-
ately. For the command hash table this hashes all the absolute
directories in the PATH, and for the named directory hash table
this adds all users' home directories. These two options cannot
be used with any arguments.
The -m 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.
For each name with a corresponding value, put `name' in the se-
lected hash table, associating it with the pathname `value'. In
the command hash table, this means that whenever `name' is used
as a command argument, the shell will try to execute the file
given by `value'. In the named directory hash table, this means
that `value' may be referred to as `~name'.
For each name with no corresponding value, attempt to add name
to the hash table, checking what the appropriate value is in the
normal manner for that hash table. If an appropriate value
can't be found, then the hash table will be unchanged.
The -v option causes hash table entries to be listed as they are
added by explicit specification. If has no effect if used with
-f.
If the -L flag is present, then each hash table entry is printed
in the form of a call to hash.
history
Same as fc -l.
integer [ {+|-}Hghlprtux ] [ {+|-}LRZi [ n ] ] [ name[=value] ... ]
Equivalent to typeset -i, except that options irrelevant to in-
tegers are not permitted.
jobs [ -dlprs ] [ job ... ]
jobs -Z string
Lists information about each given job, or all jobs if job is
omitted. The -l flag lists process IDs, and the -p flag lists
process groups. If the -r flag is specified only running jobs
will be listed and if the -s flag is given only stopped jobs are
shown. If the -d 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.
The -Z option replaces the shell's argument and environment
space with the given string, truncated if necessary to fit.
This will normally be visible in ps (ps(1)) listings. This fea-
ture is typically used by daemons, to indicate their state.
Full job control is only available in the top-level interactive
shell, not in commands run in the left hand side of pipelines or
within the (...) construct. However, a snapshot of the job
state at that point is taken, so it is still possible to use the
jobs builtin, or any parameter providing job information. This
gives information about the state of jobs at the point the sub-
shell was created. If background processes are created within
the subshell, then instead information about those processes is
provided.
For example,
sleep 10 & # Job in background
( # Shell forks
jobs # Shows information about "sleep 10 &"
sleep 5 & # Process in background (no job control)
jobs # Shows information about "sleep 5 &"
)
kill [ -s signal_name | -n signal_number | -sig ] job ...
kill -l [ sig ... ]
Sends either SIGTERM or the specified signal to the given jobs
or processes. Signals are given by number or by names, with or
without the `SIG' prefix. If the signal being sent is not
`KILL' or `CONT', then the job will be sent a `CONT' signal if
it is stopped. The argument job can be the process ID of a job
not in the job list. In the second form, kill -l, if sig is not
specified the signal names are listed. Otherwise, for each sig
that is a name, the corresponding signal number is listed. For
each sig 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.
On some systems, alternative signal names are allowed for a few
signals. Typical examples are SIGCHLD and SIGCLD or SIGPOLL and
SIGIO, assuming they correspond to the same signal number. kill
-l will only list the preferred form, however kill -l alt will
show if the alternative form corresponds to a signal number.
For example, under Linux kill -l IO and kill -l POLL both output
29, hence kill -IO and kill -POLL have the same effect.
Many systems will allow process IDs to be negative to kill a
process group or zero to kill the current process group.
let arg ...
Evaluate each arg as an arithmetic expression. See the section
`Arithmetic Evaluation' in zshmisc(1) 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 er-
ror occurred.
limit [ -hs ] [ resource [ limit ] ] ...
Set or display resource limits. Unless the -s flag is given,
the limit applies only the children of the shell. If -s is
given without other arguments, the resource limits of the cur-
rent shell is set to the previously set resource limits of the
children.
If limit is not specified, print the current limit placed on re-
source, otherwise set the limit to the specified value. If the
-h flag is given, use hard limits instead of soft limits. If no
resource is given, print all limits.
When looping over multiple resources, the shell will abort imme-
diately if it detects a badly formed argument. However, if it
fails to set a limit for some other reason it will continue try-
ing to set the remaining limits.
resource can be one of:
addressspace
Maximum amount of address space used.
aiomemorylocked
Maximum amount of memory locked in RAM for AIO opera-
tions.
aiooperations
Maximum number of AIO operations.
cachedthreads
Maximum number of cached threads.
coredumpsize
Maximum size of a core dump.
cputime
Maximum CPU seconds per process.
datasize
Maximum data size (including stack) for each process.
descriptors
Maximum value for a file descriptor.
filesize
Largest single file allowed.
kqueues
Maximum number of kqueues allocated.
maxproc
Maximum number of processes.
maxpthreads
Maximum number of threads per process.
memorylocked
Maximum amount of memory locked in RAM.
memoryuse
Maximum resident set size.
msgqueue
Maximum number of bytes in POSIX message queues.
posixlocks
Maximum number of POSIX locks per user.
pseudoterminals
Maximum number of pseudo-terminals.
resident
Maximum resident set size.
sigpending
Maximum number of pending signals.
sockbufsize
Maximum size of all socket buffers.
stacksize
Maximum stack size for each process.
swapsize
Maximum amount of swap used.
vmemorysize
Maximum amount of virtual memory.
Which of these resource limits are available depends on the sys-
tem. resource 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.
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 -s option is
present.
limit is a number, with an optional scaling factor, as follows:
nh hours
nk kilobytes (default)
nm megabytes or minutes
ng gigabytes
[mm:]ss
minutes and seconds
The limit 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 `zmodload -F zsh/rlimits b:limit'.
local [ {+|-}AHUahlprtux ] [ {+|-}EFLRZi [ n ] ] [ name[=value] ... ]
Same as typeset, except that the options -g, and -f are not per-
mitted. In this case the -x option does not force the use of
-g, i.e. exported variables will be local to functions.
logout [ n ]
Same as exit, except that it only works in a login shell.
noglob simple command
See the section `Precommand Modifiers' in zshmisc(1).
popd [ -q ] [ {+|-}n ]
Remove an entry from the directory stack, and perform a cd to
the new top directory. With no argument, the current top entry
is removed. An argument of the form `+n' identifies a stack en-
try by counting from the left of the list shown by the dirs com-
mand, starting with zero. An argument of the form -n counts
from the right. If the PUSHD_MINUS option is set, the meanings
of `+' and `-' in this context are swapped.
If the -q (quiet) option is specified, the hook function chpwd
and the functions in the array $chpwd_functions are not called,
and the new directory stack is not printed. This is useful for
calls to popd that do not change the environment seen by an in-
teractive user.
print [ -abcDilmnNoOpPrsSz ] [ -u n ] [ -f format ] [ -C cols ]
[ -v name ] [ -xX tabstop ] [ -R [ -en ]] [ arg ... ]
With the `-f' option the arguments are printed as described by
printf. With no flags or with the flag `-', the arguments are
printed on the standard output as described by echo, with the
following differences: the escape sequence `\M-x' (or `\Mx')
metafies the character x (sets the highest bit), `\C-x' (or
`\Cx') produces a control character (`\C-@' and `\C-?' give the
characters NULL and delete), a character code in octal is repre-
sented by `\NNN' (instead of `\0NNN'), and `\E' is a synonym for
`\e'. Finally, if not in an escape sequence, `\' escapes the
following character and is not printed.
-a Print arguments with the column incrementing first. Only
useful with the -c and -C options.
-b Recognize all the escape sequences defined for the bind-
key command, see the section `Zle Builtins' in zshzle(1).
-c Print the arguments in columns. Unless -a is also given,
arguments are printed with the row incrementing first.
-C cols
Print the arguments in cols columns. Unless -a is also
given, arguments are printed with the row incrementing
first.
-D Treat the arguments as paths, replacing directory pre-
fixes with ~ expressions corresponding to directory
names, as appropriate.
-i If given together with -o or -O, sorting is performed
case-independently.
-l Print the arguments separated by newlines instead of spa-
ces. Note: if the list of arguments is empty, print -l
will still output one empty line. To print a possi-
bly-empty list of arguments one per line, use print -C1,
as in `print -rC1 -- "$list[@]"'.
-m Take the first argument as a pattern (should be quoted),
and remove it from the argument list together with subse-
quent arguments that do not match this pattern.
-n Do not add a newline to the output.
-N Print the arguments separated and terminated by nulls.
Again, print -rNC1 -- "$list[@]" is a canonical way to
print an arbitrary list as null-delimited records.
-o Print the arguments sorted in ascending order.
-O Print the arguments sorted in descending order.
-p Print the arguments to the input of the coprocess.
-P Perform prompt expansion (see EXPANSION OF PROMPT SE-
QUENCES in zshmisc(1)). In combination with `-f', prompt
escape sequences are parsed only within interpolated ar-
guments, not within the format string.
-r Ignore the escape conventions of echo.
-R Emulate the BSD echo command, which does not process es-
cape sequences unless the -e flag is given. The -n flag
suppresses the trailing newline. Only the -e and -n
flags are recognized after -R; all other arguments and
options are printed.
-s Place the results in the history list instead of on the
standard output. Each argument to the print command is
treated as a single word in the history, regardless of
its content.
-S 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 HIST_LEX_WORDS option
active.
-u n Print the arguments to file descriptor n.
-v name
Store the printed arguments as the value of the parameter
name.
-x tab-stop
Expand leading tabs on each line of output in the printed
string assuming a tab stop every tab-stop characters.
This is appropriate for formatting code that may be in-
dented with tabs. Note that leading tabs of any argument
to print, not just the first, are expanded, even if print
is using spaces to separate arguments (the column count
is maintained across arguments but may be incorrect on
output owing to previous unexpanded tabs).
The start of the output of each print command is assumed
to be aligned with a tab stop. Widths of multibyte char-
acters are handled if the option MULTIBYTE is in effect.
This option is ignored if other formatting options are in
effect, namely column alignment or printf style, or if
output is to a special location such as shell history or
the command line editor.
-X tab-stop
This is similar to -x, 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 for-
mat.
-z Push the arguments onto the editing buffer stack, sepa-
rated by spaces.
If any of `-m', `-o' or `-O' are used in combination with `-f'
and there are no arguments (after the removal process in the
case of `-m') then nothing is printed.
printf [ -v name ] format [ arg ... ]
Print the arguments according to the format specification. For-
matting rules are the same as used in C. The same escape se-
quences as for echo are recognised in the format. All C conver-
sion specifications ending in one of csdiouxXeEfgGn are handled.
In addition to this, `%b' can be used instead of `%s' to cause
escape sequences in the argument to be recognised and `%q' 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 the section `Arithmetic Evaluation' in zsh-
misc(1) for a description of arithmetic expressions. With `%n',
the corresponding argument is taken as an identifier which is
created as an integer parameter.
Normally, conversion specifications are applied to each argument
in order but they can explicitly specify the nth argument is to
be used by replacing `%' by `%n$' and `*' by `*n$'. It is rec-
ommended 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.
If arguments remain unused after formatting, the format string
is reused until all arguments have been consumed. With the print
builtin, this can be suppressed by using the -r 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 speci-
fied as the argument.
The -v option causes the output to be stored as the value of the
parameter name, instead of printed. If name 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.
pushd [ -qsLP ] [ arg ]
pushd [ -qsLP ] old new
pushd [ -qsLP ] {+|-}n
Change the current directory, and push the old current directory
onto the directory stack. In the first form, change the current
directory to arg. If arg is not specified, change to the second
directory on the stack (that is, exchange the top two entries),
or change to $HOME if the PUSHD_TO_HOME option is set or if
there is only one entry on the stack. Otherwise, arg is inter-
preted as it would be by cd. The meaning of old and new in the
second form is also the same as for cd.
The third form of pushd changes directory by rotating the direc-
tory list. An argument of the form `+n' identifies a stack en-
try by counting from the left of the list shown by the dirs com-
mand, starting with zero. An argument of the form `-n' counts
from the right. If the PUSHD_MINUS option is set, the meanings
of `+' and `-' in this context are swapped.
If the -q (quiet) option is specified, the hook function chpwd
and the functions in the array $chpwd_functions are not called,
and the new directory stack is not printed. This is useful for
calls to pushd that do not change the environment seen by an in-
teractive user.
If the option -q is not specified and the shell option
PUSHD_SILENT is not set, the directory stack will be printed af-
ter a pushd is performed.
The options -s, -L and -P have the same meanings as for the cd
builtin.
pushln [ arg ... ]
Equivalent to print -nz.
pwd [ -rLP ]
Print the absolute pathname of the current working directory.
If the -r or the -P flag is specified, or the CHASE_LINKS option
is set and the -L flag is not given, the printed path will not
contain symbolic links.
r Same as fc -e -.
read [ -rszpqAclneE ] [ -t [ num ] ] [ -k [ num ] ] [ -d delim ]
[ -u n ] [ [name][?prompt] ] [ name ... ]
Read one line and break it into fields using the characters in
$IFS as separators, except as noted below. The first field is
assigned to the first name, the second field to the second name,
etc., with leftover fields assigned to the last name. If name
is omitted then REPLY is used for scalars and reply for arrays.
-r Raw mode: a `\' 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.
-s Don't echo back characters if reading from the terminal.
-q Read only one character from the terminal and set name to
`y' if this character was `y' or `Y' and to `n' other-
wise. With this flag set the return status is zero only
if the character was `y' or `Y'. This option may be used
with a timeout (see -t); if the read times out, or en-
counters end of file, status 2 is returned. Input is
read from the terminal unless one of -u or -p is present.
This option may also be used within zle widgets.
-k [ num ]
Read only one (or num) characters. All are assigned to
the first name, without word splitting. This flag is ig-
nored when -q is present. Input is read from the termi-
nal unless one of -u or -p is present. This option may
also be used within zle widgets.
Note that despite the mnemonic `key' this option does
read full characters, which may consist of multiple bytes
if the option MULTIBYTE is set.
-z Read one entry from the editor buffer stack and assign it
to the first name, without word splitting. Text is
pushed onto the stack with `print -z' or with push-line
from the line editor (see zshzle(1)). This flag is ig-
nored when the -k or -q flags are present.
-e
-E The input read is printed (echoed) to the standard out-
put. If the -e flag is used, no input is assigned to the
parameters.
-A The first name is taken as the name of an array and all
words are assigned to it.
-c
-l These flags are allowed only if called inside a function
used for completion (specified with the -K flag to com-
pctl). If the -c flag is given, the words of the current
command are read. If the -l flag is given, the whole line
is assigned as a scalar. If both flags are present, -l
is used and -c is ignored.
-n Together with -c, the number of the word the cursor is on
is read. With -l, 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.
-u n Input is read from file descriptor n.
-p Input is read from the coprocess.
-d delim
Input is terminated by the first character of delim in-
stead of by newline.
-t [ num ]
Test if input is available before attempting to read. If
num 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 num is not
present, it is taken to be zero, so that read returns im-
mediately if no input is available. If no input is
available, return status 1 and do not set any variables.
This option is not available when reading from the editor
buffer with -z, when called from within completion with
-c or -l, with -q which clears the input queue before
reading, or within zle where other mechanisms should be
used to test for input.
Note that read does not attempt to alter the input pro-
cessing mode. The default mode is canonical input, in
which an entire line is read at a time, so usually `read
-t' will not read anything until an entire line has been
typed. However, when reading from the terminal with -k
input is processed one key at a time; in this case, only
availability of the first character is tested, so that
e.g. `read -t -k 2' can still block on the second charac-
ter. Use two instances of `read -t -k' if this is not
what is wanted.
If the first argument contains a `?', the remainder of this word
is used as a prompt on standard error when the shell is interac-
tive.
The value (exit status) of read is 1 when an end-of-file is en-
countered, or when -c or -l is present and the command is not
called from a compctl function, or as described for -q. Other-
wise the value is 0.
The behavior of some combinations of the -k, -p, -q, -u and -z
flags is undefined. Presently -q cancels all the others, -p
cancels -u, -k cancels -z, and otherwise -z cancels both -p and
-u.
The -c or -l flags cancel any and all of -kpquz.
readonly
Same as typeset -r. With the POSIX_BUILTINS option set, same as
typeset -gr.
rehash Same as hash -r.
return [ n ]
Causes a shell function or `.' script to return to the invoking
script with the return status specified by an arithmetic expres-
sion n. For example, the following prints `42':
() { integer foo=40; return "foo + 2" }
echo $?
If n is omitted, the return status is that of the last command
executed.
If return was executed from a trap in a TRAPNAL 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 pro-
cessing; with a non-zero status, the shell will behave as inter-
rupted 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 `return
"128+$1"' will return the same status as if the signal had not
been trapped.
sched See the section `The zsh/sched Module' in zshmodules(1).
set [ {+|-}options | {+|-}o [ option_name ] ] ... [ {+|-}A [ name ] ]
[ arg ... ]
Set the options for the shell and/or set the positional parame-
ters, or declare and set an array. If the -s option is given,
it causes the specified arguments to be sorted before assigning
them to the positional parameters (or to the array name if -A is
used). With +s sort arguments in descending order. For the
meaning of the other flags, see zshoptions(1). Flags may be
specified by name using the -o option. If no option name is sup-
plied with -o, the current option states are printed: see the
description of setopt below for more information on the format.
With +o they are printed in a form that can be used as input to
the shell.
If the -A flag is specified, name is set to an array containing
the given args; if no name is specified, all arrays are printed
together with their values.
If +A is used and name is an array, the given arguments will re-
place the initial elements of that array; if no name is speci-
fied, all arrays are printed without their values.
The behaviour of arguments after -A name or +A name depends on
whether the option KSH_ARRAYS is set. If it is not set, all ar-
guments following name are treated as values for the array, re-
gardless 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
set -A array -x -- foo
sets array to `-x -- foo' if KSH_ARRAYS is not set, but sets the
array to foo and turns on the option `-x' if it is set.
If the -A 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 `--', and there are no further
arguments, the positional parameters will be unset.
If no arguments and no `--' are given, then the names and values
of all parameters are printed on the standard output. If the
only argument is `+', the names of all parameters are printed.
For historical reasons, `set -' is treated as `set +xv' and `set
- args' as `set +xv -- args' when in any other emulation mode
than zsh's native mode.
setcap See the section `The zsh/cap Module' in zshmodules(1).
setopt [ {+|-}options | {+|-}o option_name ] [ -m ] [ name ... ]
Set the options for the shell. All options specified either
with flags or by name are set.
If no arguments are supplied, the names of all options currently
set are printed. The form is chosen so as to minimize the dif-
ferences from the default options for the current emulation (the
default emulation being native zsh, shown as <Z> in zshop-
tions(1)). Options that are on by default for the emulation are
shown with the prefix no only if they are off, while other op-
tions are shown without the prefix no 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 ex-
ample, SHIN_STDIN or INTERACTIVE) will be shown in the list.
The format is further modified by the option KSH_OPTION_PRINT,
however the rationale for choosing options with or without the
no prefix remains the same in this case.
If the -m flag is given the arguments are taken as patterns
(which should be quoted to protect them from filename expan-
sion), and all options with names matching these patterns are
set.
Note that a bad option name does not cause execution of subse-
quent shell code to be aborted; this is behaviour is different
from that of `set -o'. This is because set is regarded as a
special builtin by the POSIX standard, but setopt is not.
shift [ -p ] [ n ] [ name ... ]
The positional parameters ${n+1} ... are renamed to $1 ...,
where n is an arithmetic expression that defaults to 1. If any
names are given then the arrays with these names are shifted in-
stead of the positional parameters.
If the option -p is given arguments are instead removed (popped)
from the end rather than the start of the array.
source file [ arg ... ]
Same as `.', except that the current directory is always
searched and is always searched first, before directories in
$path.
stat See the section `The zsh/stat Module' in zshmodules(1).
suspend [ -f ]
Suspend the execution of the shell (send it a SIGTSTP) until it
receives a SIGCONT. Unless the -f option is given, this will
refuse to suspend a login shell.
test [ arg ... ]
[ [ arg ... ] ]
Like the system version of test. Added for compatibility; use
conditional expressions instead (see the section `Conditional
Expressions'). The main differences between the conditional ex-
pression syntax and the test and [ 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 arith-
metic expressions.
The command attempts to implement POSIX and its extensions where
these are specified. Unfortunately there are intrinsic ambigui-
ties in the syntax; in particular there is no distinction be-
tween test operators and strings that resemble them. The stan-
dard 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 `[['
test syntax which does not have these ambiguities.
times Print the accumulated user and system times for the shell and
for processes run from the shell.
trap [ arg ] [ sig ... ]
arg 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
sig args. Each sig can be given as a number, or as the name of
a signal either with or without the string SIG in front (e.g. 1,
HUP, and SIGHUP are all the same signal).
If arg is `-', then the specified signals are reset to their de-
faults, or, if no sig args are present, all traps are reset.
If arg is an empty string, then the specified signals are ig-
nored by the shell (and by the commands it invokes).
If arg is omitted but one or more sig args are provided (i.e.
the first argument is a valid signal number or name), the effect
is the same as if arg had been specified as `-'.
The trap command with no arguments prints a list of commands as-
sociated with each signal.
If sig is ZERR then arg will be executed after each command with
a nonzero exit status. ERR is an alias for ZERR on systems that
have no SIGERR signal (this is the usual case).
If sig is DEBUG then arg will be executed before each command if
the option DEBUG_BEFORE_CMD 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 the section SIMPLE COMMANDS
& PIPELINES in zshmisc(1). If DEBUG_BEFORE_CMD is set various
additional features are available. First, it is possible to
skip the next command by setting the option ERR_EXIT; see the
description of the ERR_EXIT option in zshoptions(1). Also, the
shell parameter ZSH_DEBUG_CMD 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 parame-
ter is unset after the trap is executed.
If sig is 0 or EXIT and the trap statement is executed inside
the body of a function, then the command arg is executed after
the function completes. The value of $? at the start of execu-
tion is the exit status of the shell or the return status of the
function exiting. If sig is 0 or EXIT and the trap statement is
not executed inside the body of a function, then the command arg
is executed when the shell terminates; the trap runs before any
zshexit hook functions.
ZERR, DEBUG, and EXIT traps are not executed inside other traps.
ZERR and DEBUG traps are kept within subshells, while other
traps are reset.
Note that traps defined with the trap builtin are slightly dif-
ferent from those defined as `TRAPNAL () { ... }', as the latter
have their own function environment (line numbers, local vari-
ables, etc.) while the former use the environment of the command
in which they were called. For example,
trap 'print $LINENO' DEBUG
will print the line number of a command executed after it has
run, while
TRAPDEBUG() { print $LINENO; }
will always print the number zero.
Alternative signal names are allowed as described under kill
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 an-
other.
true [ arg ... ]
Do nothing and return an exit status of 0.
ttyctl [ -fu ]
The -f option freezes the tty (i.e. terminal or terminal emula-
tor), and -u 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, stty and sim-
ilar programs have no effect when the tty is frozen. Freezing
the tty does not cause the current state to be remembered: in-
stead, it causes future changes to the state to be blocked.
Without options it reports whether the terminal is frozen or
not.
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 STTY for a means of initialising the tty
before running external commands and/or freezing the tty around
a single command.
type [ -wfpamsS ] name ...
Equivalent to whence -v.
typeset [ {+|-}AHUaghlmrtux ] [ {+|-}EFLRZip [ n ] ]
[ + ] [ name[=value] ... ]
typeset -T [ {+|-}Uglrux ] [ {+|-}LRZp [ n ] ]
[ + | SCALAR[=value] array[=(value ...)] [ sep ] ]
typeset -f [ {+|-}TUkmtuz ] [ + ] [ name ... ]
Set or display attributes and values for shell parameters.
Except as noted below for control flags that change the behav-
ior, a parameter is created for each name that does not already
refer to one. When inside a function, a new parameter is cre-
ated for every name (even those that already exist), and is un-
set again when the function completes. See `Local Parameters'
in zshparam(1). The same rules apply to special shell parame-
ters, which retain their special attributes when made local.
For each name=value assignment, the parameter name is set to
value. If the assignment is omitted and name does not refer to
an existing parameter, a new parameter is initialized to empty
string, zero, or empty array (as appropriate), unless the shell
option TYPESET_TO_UNSET is set. When that option is set, the
parameter attributes are recorded but the parameter remains un-
set.
If the shell option TYPESET_SILENT is not set, for each remain-
ing name 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
name. Using `+' instead of minus to introduce an attribute
turns it off.
If no name is present, the names and values of all parameters
are printed. In this case the attribute flags restrict the dis-
play to only those parameters that have the specified at-
tributes, and using `+' rather than `-' to introduce the flag
suppresses printing of the values of parameters when there is no
parameter name.
All forms of the command handle scalar assignment. Array as-
signment is possible if any of the reserved words declare, ex-
port, float, integer, local, readonly or typeset 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 `+='
syntax and the GLOB_ASSIGN option are not supported, and scalar
values after = are not split further into words, even if ex-
panded (regardless of the setting of the KSH_TYPESET option;
this option is obsolete).
Examples of the differences between command and reserved word
parsing:
# Reserved word parsing
typeset svar=$(echo one word) avar=(several words)
The above creates a scalar parameter svar and an array parameter
avar as if the assignments had been
svar="one word"
avar=(several words)
On the other hand:
# Normal builtin interface
builtin typeset svar=$(echo two words)
The builtin keyword causes the above to use the standard builtin
interface to typeset in which argument parsing is performed in
the same way as for other commands. This example creates a
scalar svar containing the value two and another scalar parame-
ter words with no value. An array value in this case would ei-
ther cause an error or be treated as an obscure set of glob
qualifiers.
Arbitrary arguments are allowed if they take the form of assign-
ments after command line expansion; however, these only perform
scalar assignment:
var='svar=val'
typeset $var
The above sets the scalar parameter svar to the value val.
Parentheses around the value within var would not cause array
assignment as they will be treated as ordinary characters when
$var is substituted. Any non-trivial expansion in the name part
of the assignment causes the argument to be treated in this
fashion:
typeset {var1,var2,var3}=name
The above syntax is valid, and has the expected effect of set-
ting the three parameters to the same value, but the command
line is parsed as a set of three normal command line arguments
to typeset after expansion. Hence it is not possible to assign
to multiple arrays by this means.
Note that each interface to any of the commands may be disabled
separately. For example, `disable -r typeset' disables the re-
served word interface to typeset, exposing the builtin inter-
face, while `disable typeset' disables the builtin. Note that
disabling the reserved word interface for typeset may cause
problems with the output of `typeset -p', which assumes the re-
served word interface is available in order to restore array and
associative array values.
Unlike parameter assignment statements, typeset's exit status on
an assignment that involves a command substitution does not re-
flect the exit status of the command substitution. Therefore,
to test for an error in a command substitution, separate the
declaration of the parameter from its initialization:
# WRONG
typeset var1=$(exit 1) || echo "Trouble with var1"
# RIGHT
typeset var1 && var1=$(exit 1) || echo "Trouble with var1"
To initialize a parameter param to a command output and mark it
readonly, use typeset -r param or readonly param after the pa-
rameter assignment statement.
If no attribute flags are given, and either no name arguments
are present or the flag +m is used, then each parameter name
printed is preceded by a list of the attributes of that parame-
ter (array, association, exported, float, integer, readonly, or
undefined for autoloaded parameters not yet loaded). If +m is
used with attribute flags, and all those flags are introduced
with +, the matching parameter names are printed but their val-
ues are not.
The following control flags change the behavior of typeset:
+ If `+' appears by itself in a separate word as the last
option, then the names of all parameters (functions with
-f) are printed, but the values (function bodies) are
not. No name arguments may appear, and it is an error
for any other options to follow `+'. The effect of `+'
is as if all attribute flags which precede it were given
with a `+' prefix. For example, `typeset -U +' is equiv-
alent to `typeset +U' and displays the names of all ar-
rays having the uniqueness attribute, whereas `typeset -f
-U +' displays the names of all autoloadable functions.
If + is the only option, then type information (array,
readonly, etc.) is also printed for each parameter, in
the same manner as `typeset +m "*"'.
-g The -g (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 ef-
fect when listing existing parameters, nor does the flag
+g have any effect except in combination with -m (see be-
low).
-m If the -m flag is given the name arguments are taken as
patterns (use quoting to prevent these from being inter-
preted as file patterns). With no attribute flags, all
parameters (or functions with the -f flag) with matching
names are printed (the shell option TYPESET_SILENT is not
used in this case).
If the +g flag is combined with -m, a new local parameter
is created for every matching parameter that is not al-
ready local. Otherwise -m applies all other flags or as-
signments to the existing parameters.
Except when assignments are made with name=value, using
+m forces the matching parameters and their attributes to
be printed, even inside a function. Note that -m is ig-
nored if no patterns are given, so `typeset -m' displays
attributes but `typeset -a +m' does not.
-p [ n ]
If the -p option is given, parameters and values are
printed in the form of a typeset command with an assign-
ment, regardless of other flags and options. Note that
the -H flag on parameters is respected; no value will be
shown for these parameters.
-p may be followed by an optional integer argument. Cur-
rently only the value 1 is supported. In this case ar-
rays and associative arrays are printed with newlines be-
tween indented elements for readability.
-T [ scalar[=value] array[=(value ...)] [ sep ] ]
This flag has a different meaning when used with -f; see
below. Otherwise the -T 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 $PATH and
$path. 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 $PATH. Only the first character of the separator is
significant; any remaining characters are ignored.
Multibyte characters are not yet supported.
Only one of the scalar and array parameters may be as-
signed an initial value (the restrictions on assignment
forms described above also apply).
Both the scalar and the array may be manipulated as nor-
mal. If one is unset, the other will automatically be
unset too. There is no way of untying the variables
without unsetting them, nor of converting the type of one
of them with another typeset command; +T does not work,
assigning an array to scalar is an error, and assigning a
scalar to array sets it to be a single-element array.
Note that both `typeset -xT ...' and `export -T ...'
work, but only the scalar will be marked for export.
Setting the value using the scalar version causes a split
on all separators (which cannot be quoted). It is possi-
ble to apply -T to two previously tied variables but with
a different separator character, in which case the vari-
ables remain joined as before but the separator is
changed.
When an existing scalar is tied to a new array, the value
of the scalar is preserved but no attribute other than
export will be preserved.
Attribute flags that transform the final value (-L, -R, -Z, -l,
-u) are only applied to the expanded value at the point of a pa-
rameter expansion expression using `$'. They are not applied
when a parameter is retrieved internally by the shell for any
purpose.
The following attribute flags may be specified:
-A The names refer to associative array parameters; see `Ar-
ray Parameters' in zshparam(1).
-L [ n ]
Left justify and remove leading blanks from the value
when the parameter is expanded. If n is nonzero, it de-
fines the width of the field. If n is zero, the width is
determined by the width of the value of the first assign-
ment. 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.
The width is the count of characters, which may be multi-
byte characters if the MULTIBYTE option is in effect.
Note that the screen width of the character is not taken
into account; if this is required, use padding with pa-
rameter expansion flags ${(ml...)...} as described in
`Parameter Expansion Flags' in zshexpn(1).
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 nu-
meric parameters. Leading zeros are removed if the -Z
flag is also set.
-R [ n ]
Similar to -L, 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 com-
bined with the -Z flag.
-U For arrays (but not for associative arrays), keep only
the first occurrence of each duplicated value. This may
also be set for tied parameters (see -T) or colon-sepa-
rated special parameters like PATH or FIGNORE, etc. Note
the flag takes effect on assignment, and the type of the
variable being assigned to is determinative; for vari-
ables with shared values it is therefore recommended to
set the flag for all interfaces, e.g. `typeset -U PATH
path'.
This flag has a different meaning when used with -f; see
below.
-Z [ n ]
Specially handled if set along with the -L flag. Other-
wise, similar to -R, 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 ze-
roes, and the zeroes are inserted at an appropriate place
in the output.
-a The names refer to array parameters. An array parameter
may be created this way, but it may be assigned to in the
typeset statement only if the reserved word form of type-
set is enabled (as it is by default). When displaying,
both normal and associative arrays are shown.
-f The names refer to functions rather than parameters. No
assignments can be made, and the only other valid flags
are -t, -T, -k, -u, -U and -z. The flag -t turns on exe-
cution tracing for this function; the flag -T does the
same, but turns off tracing for any named (not anonymous)
function called from the present one, unless that func-
tion also has the -t or -T flag. The -u and -U flags
cause the function to be marked for autoloading; -U also
causes alias expansion to be suppressed when the function
is loaded. See the description of the `autoload' builtin
for details.
Note that the builtin functions provides the same basic
capabilities as typeset -f but gives access to a few ex-
tra options; autoload gives further additional options
for the case typeset -fu and typeset -fU.
-h Hide: only useful for special parameters (those marked
`<S>' in the table in zshparam(1)), and for local parame-
ters with the same name as a special parameter, though
harmless for others. A special parameter with this at-
tribute will not retain its special effect when made lo-
cal. Thus after `typeset -h PATH', a function containing
`typeset PATH' will create an ordinary local parameter
without the usual behaviour of PATH. Alternatively, the
local parameter may itself be given this attribute; hence
inside a function `typeset -h PATH' creates an ordinary
local parameter and the special PATH parameter is not al-
tered in any way. It is also possible to create a local
parameter using `typeset +h special', where the local
copy of special will retain its special properties re-
gardless of having the -h attribute. Global special pa-
rameters loaded from shell modules (currently those in
zsh/mapfile and zsh/parameter) are automatically given
the -h attribute to avoid name clashes.
-H Hide value: specifies that typeset will not display the
value of the parameter when listing parameters; the dis-
play for such parameters is always as if the `+' 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 -m option.
This is on by default for the parameters in the zsh/pa-
rameter and zsh/mapfile modules. Note, however, that un-
like the -h flag this is also useful for non-special pa-
rameters.
-i [ n ]
Use an internal integer representation. If n is nonzero
it defines the output arithmetic base, otherwise it is
determined by the first assignment. Bases from 2 to 36
inclusive are allowed.
-E [ n ]
Use an internal double-precision floating point represen-
tation. On output the variable will be converted to sci-
entific notation. If n is nonzero it defines the number
of significant figures to display; the default is ten.
-F [ n ]
Use an internal double-precision floating point represen-
tation. On output the variable will be converted to
fixed-point decimal notation. If n is nonzero it defines
the number of digits to display after the decimal point;
the default is ten.
-l Convert the result to lower case whenever the parameter
is expanded. The value is not converted when assigned.
-r The given names are marked readonly. Note that if name
is a special parameter, the readonly attribute can be
turned on, but cannot then be turned off.
If the POSIX_BUILTINS option is set, the readonly attri-
bute is more restrictive: unset variables can be marked
readonly and cannot then be set; furthermore, the read-
only attribute cannot be removed from any variable.
It is still possible to change other attributes of the
variable though, some of which like -U or -Z would affect
the value. More generally, the readonly attribute should
not be relied on as a security mechanism.
Note that in zsh (like in pdksh but unlike most other
shells) it is still possible to create a local variable
of the same name as this is considered a different vari-
able (though this variable, too, can be marked readonly).
Special variables that have been made readonly retain
their value and readonly attribute when made local.
-t Tags the named parameters. Tags have no special meaning
to the shell. This flag has a different meaning when
used with -f; see above.
-u Convert the result to upper case whenever the parameter
is expanded. The value is not converted when assigned.
This flag has a different meaning when used with -f; see
above.
-x Mark for automatic export to the environment of subse-
quently executed commands. If the option GLOBAL_EXPORT
is set, this implies the option -g, unless +g is also ex-
plicitly given; in other words the parameter is not made
local to the enclosing function. This is for compatibil-
ity with previous versions of zsh.
ulimit [ -HSa ] [ { -bcdfiklmnpqrsTtvwx | -N resource } [ limit ] ... ]
Set or display resource limits of the shell and the processes
started by the shell. The value of limit can be a number in the
unit specified below or one of the values `unlimited', which re-
moves the limit on the resource, or `hard', which uses the cur-
rent value of the hard limit on the resource.
By default, only soft limits are manipulated. If the -H flag is
given use hard limits instead of soft limits. If the -S flag is
given together with the -H flag set both hard and soft limits.
If no options are used, the file size limit (-f) is assumed.
If limit 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.
When looping over multiple resources, the shell will abort imme-
diately if it detects a badly formed argument. However, if it
fails to set a limit for some other reason it will continue try-
ing to set the remaining limits.
Not all the following resources are supported on all systems.
Running ulimit -a will show which are supported.
-a Lists all of the current resource limits.
-b Socket buffer size in bytes (N.B. not kilobytes)
-c 512-byte blocks on the size of core dumps.
-d Kilobytes on the size of the data segment.
-f 512-byte blocks on the size of files written.
-i The number of pending signals.
-k The number of kqueues allocated.
-l Kilobytes on the size of locked-in memory.
-m Kilobytes on the size of physical memory.
-n open file descriptors.
-p The number of pseudo-terminals.
-q Bytes in POSIX message queues.
-r Maximum real time priority. On some systems where this
is not available, such as NetBSD, this has the same ef-
fect as -T for compatibility with sh.
-s Kilobytes on the size of the stack.
-T The number of simultaneous threads available to the user.
-t CPU seconds to be used.
-u The number of processes available to the user.
-v Kilobytes on the size of virtual memory. On some systems
this refers to the limit called `address space'.
-w Kilobytes on the size of swapped out memory.
-x The number of locks on files.
A resource may also be specified by integer in the form `-N re-
source', where resource 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 corre-
spond to option letters. Such limits will be shown by number in
the output of `ulimit -a'.
The number may alternatively be out of the range of limits com-
piled into the shell. The shell will try to read or write the
limit anyway, and will report an error if this fails.
umask [ -S ] [ mask ]
The umask is set to mask. mask can be either an octal number or
a symbolic value as described in the chmod(1) man page. If mask
is omitted, the current value is printed. The -S 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.
unalias [ -ams ] name ...
Removes aliases. This command works the same as unhash -a, ex-
cept that the -a option removes all regular or global aliases,
or with -s all suffix aliases: in this case no name arguments
may appear. The options -m (remove by pattern) and -s without
-a (remove listed suffix aliases) behave as for unhash -a. Note
that the meaning of -a is different between unalias and unhash.
unfunction
Same as unhash -f.
unhash [ -adfms ] name ...
Remove the element named name from an internal hash table. The
default is remove elements from the command hash table. The -a
option causes unhash 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 -s option causes unhash to remove suffix aliases.
The -f option causes unhash to remove shell functions. The -d
options causes unhash to remove named directories. If the -m
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.
unlimit [ -hs ] resource ...
The resource limit for each resource is set to the hard limit.
If the -h flag is given and the shell has appropriate privi-
leges, the hard resource limit for each resource is removed.
The resources of the shell process are only changed if the -s
flag is given.
The unlimit 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 `zmodload -F zsh/rlimits b:unlimit'.
unset [ -fmv ] name ...
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.
Individual elements of associative array parameters may be unset
by using subscript syntax on name, which should be quoted (or
the entire command prefixed with noglob) to protect the sub-
script from filename generation.
If the -m 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.
The -v flag specifies that name refers to parameters. This is
the default behaviour.
unset -f is equivalent to unfunction.
unsetopt [ {+|-}options | {+|-}o option_name ] [ name ... ]
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 -m
flag is given the arguments are taken as patterns (which should
be quoted to preserve them from being interpreted as glob pat-
terns), and all options with names matching these patterns are
unset.
vared See the section `Zle Builtins' in zshzle(1).
wait [ job ... ]
Wait for the specified jobs or processes. If job is not given
then all currently active child processes are waited for. Each
job 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. If job represents an unknown job or process
ID, a warning is printed (unless the POSIX_BUILTINS option is
set) and the exit status is 127.
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 $! 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 CHILD_MAX. When
this limit is reached, older process IDs are discarded, least
recently started processes first.
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 pro-
cesses are not recorded, and that the user is potentially inter-
ested in both, so this problem is intrinsic to process IDs.
whence [ -vcwfpamsS ] [ -x num ] name ...
For each name, indicate how it would be interpreted if used as a
command name.
If name is not an alias, built-in command, external command,
shell function, hashed command, or a reserved word, the exit
status shall be non-zero, and -- if -v, -c, or -w was passed --
a message will be written to standard output. (This is differ-
ent from other shells that write that message to standard er-
ror.)
whence is most useful when name is only the last path component
of a command, i.e. does not include a `/'; in particular, pat-
tern matching only succeeds if just the non-directory component
of the command is passed.
-v Produce a more verbose report.
-c Print the results in a csh-like format. This takes
precedence over -v.
-w For each name, print `name: word' where word is one of
alias, builtin, command, function, hashed, reserved or
none, according as name corresponds to an alias, a
built-in command, an external command, a shell function,
a command defined with the hash builtin, a reserved word,
or is not recognised. This takes precedence over -v and
-c.
-f Causes the contents of a shell function to be displayed,
which would otherwise not happen unless the -c flag were
used.
-p Do a path search for name even if it is an alias, re-
served word, shell function or builtin.
-a Do a search for all occurrences of name throughout the
command path. Normally only the first occurrence is
printed.
-m The arguments are taken as patterns (pattern characters
should be quoted), and the information is displayed for
each command matching one of these patterns.
-s If a pathname contains symlinks, print the symlink-free
pathname as well.
-S As -s, but if the pathname had to be resolved by follow-
ing multiple symlinks, the intermediate steps are
printed, too. The symlink resolved at each step might be
anywhere in the path.
-x num Expand tabs when outputting shell functions using the -c
option. This has the same effect as the -x option to the
functions builtin.
where [ -wpmsS ] [ -x num ] name ...
Equivalent to whence -ca.
which [ -wpamsS ] [ -x num ] name ...
Equivalent to whence -c.
zcompile [ -U ] [ -z | -k ] [ -R | -M ] file [ name ... ]
zcompile -ca [ -m ] [ -R | -M ] file [ name ... ]
zcompile -t file [ name ... ]
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 au-
toloading of functions and sourcing of scripts by avoiding pars-
ing of the text when the files are read.
The first form (without the -c, -a or -t options) creates a com-
piled file. If only the file argument is given, the output file
has the name `file.zwc' and will be placed in the same directory
as the file. The shell will load the compiled file instead of
the normal function file when the function is autoloaded; see
the section `Autoloading Functions' in zshmisc(1) for a descrip-
tion of how autoloaded functions are searched. The extension
.zwc stands for `zsh word code'.
If there is at least one name argument, all the named files are
compiled into the output file given as the first argument. If
file does not end in .zwc, this extension is automatically ap-
pended. Files containing multiple compiled functions are called
`digest' files, and are intended to be used as elements of the
FPATH/fpath special array.
The second form, with the -c or -a options, writes the compiled
definitions for all the named functions into file. For -c, 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 -a option, in
which case the fpath is searched and the contents of the defini-
tion files for those functions, if found, are compiled into
file. If both -c and -a are given, names of both defined func-
tions and functions marked for autoloading may be given. In ei-
ther case, the functions in files written with the -c or -a op-
tion will be autoloaded as if the KSH_AUTOLOAD option were un-
set.
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 `zcompile -c' does not include the addi-
tional functions defined in the file, and any other initializa-
tion code in the file is lost. Using `zcompile -a' captures all
this extra information.
If the -m option is combined with -c or -a, the names are used
as patterns and all functions whose names match one of these
patterns will be written. If no name is given, the definitions
of all functions currently defined or marked as autoloaded will
be written.
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
fn1() { { ... } >~/logfile }
can be compiled but
fn1() { ... } >~/logfile
cannot. It is possible to use the first form of zcompile to
compile autoloadable functions that include the full function
definition instead of just the body of the function.
The third form, with the -t option, examines an existing com-
piled file. Without further arguments, the names of the origi-
nal 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 re-
turn status is set to zero if definitions for all names were
found in the compiled file, and non-zero if the definition for
at least one name was not found.
Other options:
-U Aliases are not expanded when compiling the named files.
-R When the compiled file is read, its contents are copied
into the shell's memory, rather than memory-mapped (see
-M). This happens automatically on systems that do not
support memory mapping.
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, conse-
quently wasting memory.
-M 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 -R nor -M is given, the zcompile
builtin decides what to do based on the size of the com-
piled file.
-k
-z These options are used when the compiled file contains
functions which are to be autoloaded. If -z is given, the
function will be autoloaded as if the KSH_AUTOLOAD option
is not set, even if it is set at the time the compiled
file is read, while if the -k is given, the function will
be loaded as if KSH_AUTOLOAD is set. These options also
take precedence over any -k or -z options specified to
the autoload builtin. If neither of these options is
given, the function will be loaded as determined by the
setting of the KSH_AUTOLOAD option at the time the com-
piled file is read.
These options may also appear as many times as necessary
between the listed names to specify the loading style of
all following functions, up to the next -k or -z.
The created file always contains two versions of the com-
piled 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).
zformat
See the section `The zsh/zutil Module' in zshmodules(1).
zftp See the section `The zsh/zftp Module' in zshmodules(1).
zle See the section `Zle Builtins' in zshzle(1).
zmodload [ -dL ] [ -s ] [ ... ]
zmodload -F [ -alLme -P param ] module [ [+-]feature ... ]
zmodload -e [ -A ] [ ... ]
zmodload [ -a [ -bcpf [ -I ] ] ] [ -iL ] ...
zmodload -u [ -abcdpf [ -I ] ] [ -iL ] ...
zmodload -A [ -L ] [ modalias[=module] ... ]
zmodload -R modalias ...
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 zmodload command
itself is always available and can be used to manipulate modules
built into versions of the shell executable without dynamical
loading.
Without arguments the names of all currently loaded binary mod-
ules are printed. The -L option causes this list to be in the
form of a series of zmodload commands. Forms with arguments
are:
zmodload [ -is ] name ...
zmodload -u [ -i ] name ...
In the simplest case, zmodload loads a binary module.
The module must be in a file with a name consisting of
the specified name followed by a standard suffix, usually
`.so' (`.sl' on HPUX). If the module to be loaded is al-
ready loaded the duplicate module is ignored. If zmod-
load 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 -i is accepted for com-
patibility but has no effect.
The named module is searched for in the same way a com-
mand is, using $module_path instead of $path. However,
the path search is performed even when the module name
contains a `/', which it usually does. There is no way
to prevent the path search.
If the module supports features (see below), zmodload
tries to enable all features when loading a module. If
the module was successfully loaded but not all features
could be enabled, zmodload returns status 2.
If the option -s 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 sta-
tus indicates if the module was loaded. This is appro-
priate if the caller considers the module optional.
With -u, zmodload unloads modules. The same name must be
given that was given when the module was loaded, but it
is not necessary for the module to exist in the file sys-
tem. The -i option suppresses the error if the module is
already unloaded (or was never loaded).
Each module has a boot and a cleanup function. The mod-
ule will not be loaded if its boot function fails. Simi-
larly a module can only be unloaded if its cleanup func-
tion runs successfully.
zmodload -F [ -almLe -P param ] module [ [+-]feature ... ]
zmodload -F allows more selective control over the fea-
tures provided by modules. With no options apart from
-F, the module named module is loaded, if it was not al-
ready loaded, and the list of features is set to the re-
quired state. If no features 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
+ to turn the feature on, or - to turn it off; the + 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 fea-
tures 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.
The standard features are builtins, conditions, parame-
ters and math functions; these are indicated by the pre-
fix `b:', `c:' (`C:' for an infix condition), `p:' and
`f:', respectively, followed by the name that the corre-
sponding feature would have in the shell. For example,
`b:strftime' indicates a builtin named strftime and
p:EPOCHSECONDS indicates a parameter named EPOCHSECONDS.
The module may provide other (`abstract') features of its
own as indicated by its documentation; these have no pre-
fix.
With -l or -L, features provided by the module are
listed. With -l alone, a list of features together with
their states is shown, one feature per line. With -L
alone, a zmodload -F command that would cause enabled
features of the module to be turned on is shown. With
-lL, a zmodload -F command that would cause all the fea-
tures to be set to their current state is shown. If one
of these combinations is given with the option -P param
then the parameter param is set to an array of features,
either features together with their state or (if -L alone
is given) enabled features.
With the option -L the module name may be omitted; then a
list of all enabled features for all modules providing
features is printed in the form of zmodload -F commands.
If -l is also given, the state of both enabled and dis-
abled features is output in that form.
A set of features may be provided together with -l or -L
and a module name; in that case only the state of those
features is considered. Each feature may be preceded by
+ or - but the character has no effect. If no set of
features is provided, all features are considered.
With -e, the command first tests that the module is
loaded; if it is not, status 1 is returned. If the mod-
ule 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 + or - is tested to see if is pro-
vided and in the given state. If the tests on all fea-
tures in the list succeed, status 0 is returned, else
status 1.
With -m, each entry in the given list of features is
taken as a pattern to be matched against the list of fea-
tures provided by the module. An initial + or - must be
given explicitly. This may not be combined with the -a
option as autoloads must be specified explicitly.
With -a, the given list of features is marked for au-
toload from the specified module, which may not yet be
loaded. An optional + may appear before the feature
name. If the feature is prefixed with -, any existing
autoload is removed. The options -l and -L 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
`zmodload -Fa module -feature' is issued. It is not an
error to request an autoload for a feature of a module
that is already loaded.
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 au-
toload is successful, there is no effect on the status of
the current command. If the module is already loaded at
the time when zmodload -Fa is run, an error message is
printed and status 1 returned.
zmodload -Fa can be used with the -l, -L, -e and -P op-
tions for listing and testing the existence of autoload-
able features. In this case -l is ignored if -L is spec-
ified. zmodload -FaL with no module name lists autoloads
for all modules.
Note that only standard features as described above can
be autoloaded; other features require the module to be
loaded before enabling.
zmodload -d [ -L ] [ name ]
zmodload -d name dep ...
zmodload -ud name [ dep ... ]
The -d 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 argu-
ment.
With -d and one argument, all dependencies for that mod-
ule are listed. With -d and no arguments, all module de-
pendencies are listed. This listing is by default in a
Makefile-like format. The -L option changes this format
to a list of zmodload -d commands.
If -d and -u are both used, dependencies are removed. If
only one argument is given, all dependencies for that
module are removed.
zmodload -ab [ -L ]
zmodload -ab [ -i ] name [ builtin ... ]
zmodload -ub [ -i ] builtin ...
The -ab option defines autoloaded builtins. It defines
the specified builtins. 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 `zmodload -F -a' as described
above). If only the name is given, one builtin is de-
fined, with the same name as the module. -i suppresses
the error if the builtin is already defined or au-
toloaded, but not if another builtin of the same name is
already defined.
With -ab and no arguments, all autoloaded builtins are
listed, with the module name (if different) shown in
parentheses after the builtin name. The -L option
changes this format to a list of zmodload -a commands.
If -b is used together with the -u option, it removes
builtins previously defined with -ab. This is only pos-
sible if the builtin is not yet loaded. -i suppresses
the error if the builtin is already removed (or never ex-
isted).
Autoload requests are retained if the module is subse-
quently unloaded until an explicit `zmodload -ub builtin'
is issued.
zmodload -ac [ -IL ]
zmodload -ac [ -iI ] name [ cond ... ]
zmodload -uc [ -iI ] cond ...
The -ac option is used to define autoloaded condition
codes. The cond strings give the names of the conditions
defined by the module. The optional -I option is used to
define infix condition names. Without this option prefix
condition names are defined.
If given no condition names, all defined names are listed
(as a series of zmodload commands if the -L option is
given).
The -uc option removes definitions for autoloaded condi-
tions.
zmodload -ap [ -L ]
zmodload -ap [ -i ] name [ parameter ... ]
zmodload -up [ -i ] parameter ...
The -p option is like the -b and -c options, but makes
zmodload work on autoloaded parameters instead.
zmodload -af [ -L ]
zmodload -af [ -i ] name [ function ... ]
zmodload -uf [ -i ] function ...
The -f option is like the -b, -p, and -c options, but
makes zmodload work on autoloaded math functions instead.
zmodload -a [ -L ]
zmodload -a [ -i ] name [ builtin ... ]
zmodload -ua [ -i ] builtin ...
Equivalent to -ab and -ub.
zmodload -e [ -A ] [ string ... ]
The -e option without arguments lists all loaded modules;
if the -A option is also given, module aliases corre-
sponding to loaded modules are also shown. If arguments
are provided, nothing is printed; the return status is
set to zero if all strings given as arguments are names
of loaded modules and to one if at least on string 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 -A flag is not used.
zmodload -A [ -L ] [ modalias[=module] ... ]
For each argument, if both modalias and module are given,
define modalias to be an alias for the module module. If
the module modalias is ever subsequently requested, ei-
ther via a call to zmodload or implicitly, the shell will
attempt to load module instead. If module is not given,
show the definition of modalias. If no arguments are
given, list all defined module aliases. When listing, if
the -L flag was also given, list the definition as a
zmodload command to recreate the alias.
The existence of aliases for modules is completely inde-
pendent of whether the name resolved is actually loaded
as a module: while the alias exists, loading and unload-
ing the module under any alias has exactly the same ef-
fect as using the resolved name, and does not affect the
connection between the alias and the resolved name which
can be removed either by zmodload -R 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, `any/old/alias' is always a valid alias.
Dependencies added to aliased modules are actually added
to the resolved module; these remain if the alias is re-
moved. 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.
Apart from the above, aliases can be used in the zmodload
command anywhere module names are required. However,
aliases will not be shown in lists of loaded modules with
a bare `zmodload'.
zmodload -R modalias ...
For each modalias argument that was previously defined as
a module alias via zmodload -A, delete the alias. If any
was not defined, an error is caused and the remainder of
the line is ignored.
Note that zsh 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 avail-
able 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.
zparseopts
See the section `The zsh/zutil Module' in zshmodules(1).
zprof See the section `The zsh/zprof Module' in zshmodules(1).
zpty See the section `The zsh/zpty Module' in zshmodules(1).
zregexparse
See the section `The zsh/zutil Module' in zshmodules(1).
zsocket
See the section `The zsh/net/socket Module' in zshmodules(1).
zstyle See the section `The zsh/zutil Module' in zshmodules(1).
ztcp See the section `The zsh/net/tcp Module' in zshmodules(1).
zsh 5.9 May 14, 2022 ZSHBUILTINS(1)
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