zshmodules(1) - phpMan

ZSHMODULES(1) General Commands Manual ZSHMODULES(1)

NAME
zshmodules - zsh loadable modules

DESCRIPTION
Some optional parts of zsh are in modules, separate from the core of the shell. Each of
these modules may be linked in to the shell at build time, or can be dynamically linked
while the shell is running if the installation supports this feature. Modules are linked
at runtime with the zmodload command, see zshbuiltins(1).

The modules that are bundled with the zsh distribution are:

zsh/attr
Builtins for manipulating extended attributes (xattr).

zsh/cap
Builtins for manipulating POSIX.1e (POSIX.6) capability (privilege) sets.

zsh/clone
A builtin that can clone a running shell onto another terminal.

zsh/compctl
The compctl builtin for controlling completion.

zsh/complete
The basic completion code.

zsh/complist
Completion listing extensions.

zsh/computil
A module with utility builtins needed for the shell function based completion sys-
tem.

zsh/curses
curses windowing commands

zsh/datetime
Some date/time commands and parameters.

zsh/db/gdbm
Builtins for managing associative array parameters tied to GDBM databases.

zsh/deltochar
A ZLE function duplicating EMACS' zap-to-char.

zsh/example
An example of how to write a module.

zsh/files
Some basic file manipulation commands as builtins.

zsh/langinfo
Interface to locale information.

zsh/mapfile
Access to external files via a special associative array.

zsh/mathfunc
Standard scientific functions for use in mathematical evaluations.

zsh/nearcolor
Map colours to the nearest colour in the available palette.

zsh/newuser
Arrange for files for new users to be installed.

zsh/parameter
Access to internal hash tables via special associative arrays.

zsh/pcre
Interface to the PCRE library.

zsh/param/private
Builtins for managing private-scoped parameters in function context.

zsh/regex
Interface to the POSIX regex library.

zsh/sched
A builtin that provides a timed execution facility within the shell.

zsh/net/socket
Manipulation of Unix domain sockets

zsh/stat
A builtin command interface to the stat system call.

zsh/system
A builtin interface to various low-level system features.

zsh/net/tcp
Manipulation of TCP sockets

zsh/termcap
Interface to the termcap database.

zsh/terminfo
Interface to the terminfo database.

zsh/zftp
A builtin FTP client.

zsh/zle
The Zsh Line Editor, including the bindkey and vared builtins.

zsh/zleparameter
Access to internals of the Zsh Line Editor via parameters.

zsh/zprof
A module allowing profiling for shell functions.

zsh/zpty
A builtin for starting a command in a pseudo-terminal.

zsh/zselect
Block and return when file descriptors are ready.

zsh/zutil
Some utility builtins, e.g. the one for supporting configuration via styles.

THE ZSH/ATTR MODULE
The zsh/attr module is used for manipulating extended attributes. The -h option causes
all commands to operate on symbolic links instead of their targets. The builtins in this
module are:

zgetattr [ -h ] filename attribute [ parameter ]
Get the extended attribute attribute from the specified filename. If the optional
argument parameter is given, the attribute is set on that parameter instead of be-
ing printed to stdout.

zsetattr [ -h ] filename attribute value
Set the extended attribute attribute on the specified filename to value.

zdelattr [ -h ] filename attribute
Remove the extended attribute attribute from the specified filename.

zlistattr [ -h ] filename [ parameter ]
List the extended attributes currently set on the specified filename. If the op-
tional argument parameter is given, the list of attributes is set on that parameter
instead of being printed to stdout.

zgetattr and zlistattr allocate memory dynamically. If the attribute or list of at-
tributes grows between the allocation and the call to get them, they return 2. On all
other errors, 1 is returned. This allows the calling function to check for this case and
retry.

THE ZSH/CAP MODULE
The zsh/cap module is used for manipulating POSIX.1e (POSIX.6) capability sets. If the
operating system does not support this interface, the builtins defined by this module will
do nothing. The builtins in this module are:

cap [ capabilities ]
Change the shell's process capability sets to the specified capabilities, otherwise
display the shell's current capabilities.

getcap filename ...
This is a built-in implementation of the POSIX standard utility. It displays the
capability sets on each specified filename.

setcap capabilities filename ...
This is a built-in implementation of the POSIX standard utility. It sets the capa-
bility sets on each specified filename to the specified capabilities.

THE ZSH/CLONE MODULE
The zsh/clone module makes available one builtin command:

clone tty
Creates a forked instance of the current shell, attached to the specified tty. In
the new shell, the PID, PPID and TTY special parameters are changed appropriately.
$! is set to zero in the new shell, and to the new shell's PID in the original
shell.

The return status of the builtin is zero in both shells if successful, and non-zero
on error.

The target of clone should be an unused terminal, such as an unused virtual console
or a virtual terminal created by

xterm -e sh -c 'trap : INT QUIT TSTP; tty;
while :; do sleep 100000000; done'

Some words of explanation are warranted about this long xterm command line: when
doing clone on a pseudo-terminal, some other session ("session" meant as a unix
session group, or SID) is already owning the terminal. Hence the cloned zsh cannot
acquire the pseudo-terminal as a controlling tty. That means two things:

o the job control signals will go to the sh-started-by-xterm process group
(that's why we disable INT QUIT and TSTP with trap; otherwise the while loop
could get suspended or killed)

o the cloned shell will have job control disabled, and the job control keys
(control-C, control-\ and control-Z) will not work.

This does not apply when cloning to an unused vc.

Cloning to a used (and unprepared) terminal will result in two processes reading
simultaneously from the same terminal, with input bytes going randomly to either
process.

clone is mostly useful as a shell built-in replacement for openvt.

THE ZSH/COMPCTL MODULE
The zsh/compctl module makes available two builtin commands. compctl, is the old, depre-
cated way to control completions for ZLE. See zshcompctl(1). The other builtin command,
compcall can be used in user-defined completion widgets, see zshcompwid(1).

THE ZSH/COMPLETE MODULE
The zsh/complete module makes available several builtin commands which can be used in
user-defined completion widgets, see zshcompwid(1).

THE ZSH/COMPLIST MODULE
The zsh/complist module offers three extensions to completion listings: the ability to
highlight matches in such a list, the ability to scroll through long lists and a different
style of menu completion.

Colored completion listings
Whenever one of the parameters ZLS_COLORS or ZLS_COLOURS is set and the zsh/complist mod-
ule is loaded or linked into the shell, completion lists will be colored. Note, however,
that complist will not automatically be loaded if it is not linked in: on systems with
dynamic loading, `zmodload zsh/complist' is required.

The parameters ZLS_COLORS and ZLS_COLOURS describe how matches are highlighted. To turn
on highlighting an empty value suffices, in which case all the default values given below
will be used. The format of the value of these parameters is the same as used by the GNU
version of the ls command: a colon-separated list of specifications of the form
`name=value'. The name may be one of the following strings, most of which specify file
types for which the value will be used. The strings and their default values are:

no 0 for normal text (i.e. when displaying something other than a matched file)

fi 0 for regular files

di 32 for directories

ln 36 for symbolic links. If this has the special value target, symbolic links are
dereferenced and the target file used to determine the display format.

pi 31 for named pipes (FIFOs)

so 33 for sockets

bd 44;37
for block devices

cd 44;37
for character devices

or none
for a symlink to nonexistent file (default is the value defined for ln)

mi none
for a non-existent file (default is the value defined for fi); this code is cur-
rently not used

su 37;41
for files with setuid bit set

sg 30;43
for files with setgid bit set

tw 30;42
for world writable directories with sticky bit set

ow 34;43
for world writable directories without sticky bit set

sa none
for files with an associated suffix alias; this is only tested after specific suf-
fixes, as described below

st 37;44
for directories with sticky bit set but not world writable

ex 35 for executable files

lc \e[ for the left code (see below)

rc m for the right code

tc 0 for the character indicating the file type printed after filenames if the
LIST_TYPES option is set

sp 0 for the spaces printed after matches to align the next column

ec none
for the end code

Apart from these strings, the name may also be an asterisk (`*') followed by any string.
The value given for such a string will be used for all files whose name ends with the
string. The name may also be an equals sign (`=') followed by a pattern; the EX-
TENDED_GLOB option will be turned on for evaluation of the pattern. The value given for
this pattern will be used for all matches (not just filenames) whose display string are
matched by the pattern. Definitions for the form with the leading equal sign take prece-
dence over the values defined for file types, which in turn take precedence over the form
with the leading asterisk (file extensions).

The leading-equals form also allows different parts of the displayed strings to be colored
differently. For this, the pattern has to use the `(#b)' globbing flag and pairs of
parentheses surrounding the parts of the strings that are to be colored differently. In
this case the value may consist of more than one color code separated by equal signs. The
first code will be used for all parts for which no explicit code is specified and the fol-
lowing codes will be used for the parts matched by the sub-patterns in parentheses. For
example, the specification `=(#b)(?)*(?)=0=3=7' will be used for all matches which are at
least two characters long and will use the code `3' for the first character, `7' for the
last character and `0' for the rest.

All three forms of name may be preceded by a pattern in parentheses. If this is given,
the value will be used only for matches in groups whose names are matched by the pattern
given in the parentheses. For example, `(g*)m*=43' highlights all matches beginning with
`m' in groups whose names begin with `g' using the color code `43'. In case of the `lc',
`rc', and `ec' codes, the group pattern is ignored.

Note also that all patterns are tried in the order in which they appear in the parameter
value until the first one matches which is then used. Patterns may be matched against
completions, descriptions (possibly with spaces appended for padding), or lines consisting
of a completion followed by a description. For consistent coloring it may be necessary to
use more than one pattern or a pattern with backreferences.

When printing a match, the code prints the value of lc, the value for the file-type or the
last matching specification with a `*', the value of rc, the string to display for the
match itself, and then the value of ec if that is defined or the values of lc, no, and rc
if ec is not defined.

The default values are ISO 6429 (ANSI) compliant and can be used on vt100 compatible ter-
minals such as xterms. On monochrome terminals the default values will have no visible
effect. The colors function from the contribution can be used to get associative arrays
containing the codes for ANSI terminals (see the section `Other Functions' in zshcon-
trib(1)). For example, after loading colors, one could use `$color[red]' to get the code
for foreground color red and `$color[bg-green]' for the code for background color green.

If the completion system invoked by compinit is used, these parameters should not be set
directly because the system controls them itself. Instead, the list-colors style should
be used (see the section `Completion System Configuration' in zshcompsys(1)).

Scrolling in completion listings
To enable scrolling through a completion list, the LISTPROMPT parameter must be set. Its
value will be used as the prompt; if it is the empty string, a default prompt will be
used. The value may contain escapes of the form `%x'. It supports the escapes `%B',
`%b', `%S', `%s', `%U', `%u', `%F', `%f', `%K', `%k' and `%{...%}' used also in shell
prompts as well as three pairs of additional sequences: a `%l' or `%L' is replaced by the
number of the last line shown and the total number of lines in the form `number/total'; a
`%m' or `%M' is replaced with the number of the last match shown and the total number of
matches; and `%p' or `%P' is replaced with `Top', `Bottom' or the position of the first
line shown in percent of the total number of lines, respectively. In each of these cases
the form with the uppercase letter will be replaced with a string of fixed width, padded
to the right with spaces, while the lowercase form will not be padded.

If the parameter LISTPROMPT is set, the completion code will not ask if the list should be
shown. Instead it immediately starts displaying the list, stopping after the first
screenful, showing the prompt at the bottom, waiting for a keypress after temporarily
switching to the listscroll keymap. Some of the zle functions have a special meaning
while scrolling lists:

send-break
stops listing discarding the key pressed

accept-line, down-history, down-line-or-history
down-line-or-search, vi-down-line-or-history
scrolls forward one line

complete-word, menu-complete, expand-or-complete
expand-or-complete-prefix, menu-complete-or-expand
scrolls forward one screenful

accept-search
stop listing but take no other action

Every other character stops listing and immediately processes the key as usual. Any key
that is not bound in the listscroll keymap or that is bound to undefined-key is looked up
in the keymap currently selected.

As for the ZLS_COLORS and ZLS_COLOURS parameters, LISTPROMPT should not be set directly
when using the shell function based completion system. Instead, the list-prompt style
should be used.

Menu selection
The zsh/complist module also offers an alternative style of selecting matches from a list,
called menu selection, which can be used if the shell is set up to return to the last
prompt after showing a completion list (see the ALWAYS_LAST_PROMPT option in zshop-
tions(1)).

Menu selection can be invoked directly by the widget menu-select defined by this module.
This is a standard ZLE widget that can be bound to a key in the usual way as described in
zshzle(1).

Alternatively, the parameter MENUSELECT can be set to an integer, which gives the minimum
number of matches that must be present before menu selection is automatically turned on.
This second method requires that menu completion be started, either directly from a widget
such as menu-complete, or due to one of the options MENU_COMPLETE or AUTO_MENU being set.
If MENUSELECT is set, but is 0, 1 or empty, menu selection will always be started during
an ambiguous menu completion.

When using the completion system based on shell functions, the MENUSELECT parameter should
not be used (like the ZLS_COLORS and ZLS_COLOURS parameters described above). Instead,
the menu style should be used with the select=... keyword.

After menu selection is started, the matches will be listed. If there are more matches
than fit on the screen, only the first screenful is shown. The matches to insert into the
command line can be selected from this list. In the list one match is highlighted using
the value for ma from the ZLS_COLORS or ZLS_COLOURS parameter. The default value for this
is `7' which forces the selected match to be highlighted using standout mode on a
vt100-compatible terminal. If neither ZLS_COLORS nor ZLS_COLOURS is set, the same termi-
nal control sequence as for the `%S' escape in prompts is used.

If there are more matches than fit on the screen and the parameter MENUPROMPT is set, its
value will be shown below the matches. It supports the same escape sequences as LIST-
PROMPT, but the number of the match or line shown will be that of the one where the mark
is placed. If its value is the empty string, a default prompt will be used.

The MENUSCROLL parameter can be used to specify how the list is scrolled. If the parame-
ter is unset, this is done line by line, if it is set to `0' (zero), the list will scroll
half the number of lines of the screen. If the value is positive, it gives the number of
lines to scroll and if it is negative, the list will be scrolled the number of lines of
the screen minus the (absolute) value.

As for the ZLS_COLORS, ZLS_COLOURS and LISTPROMPT parameters, neither MENUPROMPT nor
MENUSCROLL should be set directly when using the shell function based completion system.
Instead, the select-prompt and select-scroll styles should be used.

The completion code sometimes decides not to show all of the matches in the list. These
hidden matches are either matches for which the completion function which added them ex-
plicitly requested that they not appear in the list (using the -n option of the compadd
builtin command) or they are matches which duplicate a string already in the list (because
they differ only in things like prefixes or suffixes that are not displayed). In the list
used for menu selection, however, even these matches are shown so that it is possible to
select them. To highlight such matches the hi and du capabilities in the ZLS_COLORS and
ZLS_COLOURS parameters are supported for hidden matches of the first and second kind, re-
spectively.

Selecting matches is done by moving the mark around using the zle movement functions.
When not all matches can be shown on the screen at the same time, the list will scroll up
and down when crossing the top or bottom line. The following zle functions have special
meaning during menu selection. Note that the following always perform the same task
within the menu selection map and cannot be replaced by user defined widgets, nor can the
set of functions be extended:

accept-line, accept-search
accept the current match and leave menu selection (but do not cause the command
line to be accepted)

send-break
leaves menu selection and restores the previous contents of the command line

redisplay, clear-screen
execute their normal function without leaving menu selection

accept-and-hold, accept-and-menu-complete
accept the currently inserted match and continue selection allowing to select the
next match to insert into the line

accept-and-infer-next-history
accepts the current match and then tries completion with menu selection again; in
the case of files this allows one to select a directory and immediately attempt to
complete files in it; if there are no matches, a message is shown and one can use
undo to go back to completion on the previous level, every other key leaves menu
selection (including the other zle functions which are otherwise special during
menu selection)

undo removes matches inserted during the menu selection by one of the three functions
before

down-history, down-line-or-history
vi-down-line-or-history, down-line-or-search
moves the mark one line down

up-history, up-line-or-history
vi-up-line-or-history, up-line-or-search
moves the mark one line up

forward-char, vi-forward-char
moves the mark one column right

backward-char, vi-backward-char
moves the mark one column left

forward-word, vi-forward-word
vi-forward-word-end, emacs-forward-word
moves the mark one screenful down

backward-word, vi-backward-word, emacs-backward-word
moves the mark one screenful up

vi-forward-blank-word, vi-forward-blank-word-end
moves the mark to the first line of the next group of matches

vi-backward-blank-word
moves the mark to the last line of the previous group of matches

beginning-of-history
moves the mark to the first line

end-of-history
moves the mark to the last line

beginning-of-buffer-or-history, beginning-of-line
beginning-of-line-hist, vi-beginning-of-line
moves the mark to the leftmost column

end-of-buffer-or-history, end-of-line
end-of-line-hist, vi-end-of-line
moves the mark to the rightmost column

complete-word, menu-complete, expand-or-complete
expand-or-complete-prefix, menu-expand-or-complete
moves the mark to the next match

reverse-menu-complete
moves the mark to the previous match

vi-insert
this toggles between normal and interactive mode; in interactive mode the keys
bound to self-insert and self-insert-unmeta insert into the command line as in nor-
mal editing mode but without leaving menu selection; after each character comple-
tion is tried again and the list changes to contain only the new matches; the com-
pletion widgets make the longest unambiguous string be inserted in the command line
and undo and backward-delete-char go back to the previous set of matches

history-incremental-search-forward
history-incremental-search-backward
this starts incremental searches in the list of completions displayed; in this
mode, accept-line only leaves incremental search, going back to the normal menu se-
lection mode

All movement functions wrap around at the edges; any other zle function not listed leaves
menu selection and executes that function. It is possible to make widgets in the above
list do the same by using the form of the widget with a `.' in front. For example, the
widget `.accept-line' has the effect of leaving menu selection and accepting the entire
command line.

During this selection the widget uses the keymap menuselect. Any key that is not defined
in this keymap or that is bound to undefined-key is looked up in the keymap currently se-
lected. This is used to ensure that the most important keys used during selection (namely
the cursor keys, return, and TAB) have sensible defaults. However, keys in the menuselect
keymap can be modified directly using the bindkey builtin command (see zshmodules(1)). For
example, to make the return key leave menu selection without accepting the match currently
selected one could call

bindkey -M menuselect '^M' send-break

after loading the zsh/complist module.

THE ZSH/COMPUTIL MODULE
The zsh/computil module adds several builtin commands that are used by some of the comple-
tion functions in the completion system based on shell functions (see zshcompsys(1) ).
Except for compquote these builtin commands are very specialised and thus not very inter-
esting when writing your own completion functions. In summary, these builtin commands
are:

comparguments
This is used by the _arguments function to do the argument and command line pars-
ing. Like compdescribe it has an option -i to do the parsing and initialize some
internal state and various options to access the state information to decide what
should be completed.

compdescribe
This is used by the _describe function to build the displays for the matches and to
get the strings to add as matches with their options. On the first call one of the
options -i or -I should be supplied as the first argument. In the first case, dis-
play strings without the descriptions will be generated, in the second case, the
string used to separate the matches from their descriptions must be given as the
second argument and the descriptions (if any) will be shown. All other arguments
are like the definition arguments to _describe itself.

Once compdescribe has been called with either the -i or the -I option, it can be
repeatedly called with the -g option and the names of four parameters as its argu-
ments. This will step through the different sets of matches and store the value of
compstate[list] in the first scalar, the options for compadd in the second array,
the matches in the third array, and the strings to be displayed in the completion
listing in the fourth array. The arrays may then be directly given to compadd to
register the matches with the completion code.

compfiles
Used by the _path_files function to optimize complex recursive filename generation
(globbing). It does three things. With the -p and -P options it builds the glob
patterns to use, including the paths already handled and trying to optimize the
patterns with respect to the prefix and suffix from the line and the match specifi-
cation currently used. The -i option does the directory tests for the ignore-par-
ents style and the -r option tests if a component for some of the matches are equal
to the string on the line and removes all other matches if that is true.

compgroups
Used by the _tags function to implement the internals of the group-order style.
This only takes its arguments as names of completion groups and creates the groups
for it (all six types: sorted and unsorted, both without removing duplicates, with
removing all duplicates and with removing consecutive duplicates).

compquote [ -p ] names ...
There may be reasons to write completion functions that have to add the matches us-
ing the -Q option to compadd and perform quoting themselves. Instead of interpret-
ing the first character of the all_quotes key of the compstate special association
and using the q flag for parameter expansions, one can use this builtin command.
The arguments are the names of scalar or array parameters and the values of these
parameters are quoted as needed for the innermost quoting level. If the -p option
is given, quoting is done as if there is some prefix before the values of the pa-
rameters, so that a leading equal sign will not be quoted.

The return status is non-zero in case of an error and zero otherwise.

comptags
comptry
These implement the internals of the tags mechanism.

compvalues
Like comparguments, but for the _values function.

THE ZSH/CURSES MODULE
The zsh/curses module makes available one builtin command and various parameters.

Builtin
zcurses init
zcurses end
zcurses addwin targetwin nlines ncols begin_y begin_x [ parentwin ]
zcurses delwin targetwin
zcurses refresh [ targetwin ... ]
zcurses touch targetwin ...
zcurses move targetwin new_y new_x
zcurses clear targetwin [ redraw | eol | bot ]
zcurses position targetwin array
zcurses char targetwin character
zcurses string targetwin string
zcurses border targetwin border
zcurses attr targetwin [ [+|-]attribute | fg_col/bg_col ] [...]
zcurses bg targetwin [ [+|-]attribute | fg_col/bg_col | @char ] [...]
zcurses scroll targetwin [ on | off | [+|-]lines ]
zcurses input targetwin [ param [ kparam [ mparam ] ] ]
zcurses mouse [ delay num | [+|-]motion ]
zcurses timeout targetwin intval
zcurses querychar targetwin [ param ]
zcurses resize height width [ endwin | nosave | endwin_nosave ]
Manipulate curses windows. All uses of this command should be bracketed by
`zcurses init' to initialise use of curses, and `zcurses end' to end it; omitting
`zcurses end' can cause the terminal to be in an unwanted state.

The subcommand addwin creates a window with nlines lines and ncols columns. Its
upper left corner will be placed at row begin_y and column begin_x of the screen.
targetwin is a string and refers to the name of a window that is not currently as-
signed. Note in particular the curses convention that vertical values appear be-
fore horizontal values.

If addwin is given an existing window as the final argument, the new window is cre-
ated as a subwindow of parentwin. This differs from an ordinary new window in that
the memory of the window contents is shared with the parent's memory. Subwindows
must be deleted before their parent. Note that the coordinates of subwindows are
relative to the screen, not the parent, as with other windows.

Use the subcommand delwin to delete a window created with addwin. Note that end
does not implicitly delete windows, and that delwin does not erase the screen image
of the window.

The window corresponding to the full visible screen is called stdscr; it always ex-
ists after `zcurses init' and cannot be delete with delwin.

The subcommand refresh will refresh window targetwin; this is necessary to make any
pending changes (such as characters you have prepared for output with char) visible
on the screen. refresh without an argument causes the screen to be cleared and re-
drawn. If multiple windows are given, the screen is updated once at the end.

The subcommand touch marks the targetwins listed as changed. This is necessary be-
fore refreshing windows if a window that was in front of another window (which may
be stdscr) is deleted.

The subcommand move moves the cursor position in targetwin to new coordinates new_y
and new_x. Note that the subcommand string (but not the subcommand char) advances
the cursor position over the characters added.

The subcommand clear erases the contents of targetwin. One (and no more than one)
of three options may be specified. With the option redraw, in addition the next
refresh of targetwin will cause the screen to be cleared and repainted. With the
option eol, targetwin is only cleared to the end of the current cursor line. With
the option bot, targetwin is cleared to the end of the window, i.e everything to
the right and below the cursor is cleared.

The subcommand position writes various positions associated with targetwin into the
array named array. These are, in order:
- The y and x coordinates of the cursor relative to the top left of targetwin
- The y and x coordinates of the top left of targetwin on the screen
- The size of targetwin in y and x dimensions.

Outputting characters and strings are achieved by char and string respectively.

To draw a border around window targetwin, use border. Note that the border is not
subsequently handled specially: in other words, the border is simply a set of
characters output at the edge of the window. Hence it can be overwritten, can
scroll off the window, etc.

The subcommand attr will set targetwin's attributes or foreground/background color
pair for any successive character output. Each attribute given on the line may be
prepended by a + to set or a - to unset that attribute; + is assumed if absent.
The attributes supported are blink, bold, dim, reverse, standout, and underline.

Each fg_col/bg_col attribute (to be read as `fg_col on bg_col') sets the foreground
and background color for character output. The color default is sometimes avail-
able (in particular if the library is ncurses), specifying the foreground or back-
ground color with which the terminal started. The color pair default/default is
always available. To use more than the 8 named colors (red, green, etc.) construct
the fg_col/bg_col pairs where fg_col and bg_col are decimal integers, e.g 128/200.
The maximum color value is 254 if the terminal supports 256 colors.

bg overrides the color and other attributes of all characters in the window. Its
usual use is to set the background initially, but it will overwrite the attributes
of any characters at the time when it is called. In addition to the arguments al-
lowed with attr, an argument @char specifies a character to be shown in otherwise
blank areas of the window. Owing to limitations of curses this cannot be a multi-
byte character (use of ASCII characters only is recommended). As the specified set
of attributes override the existing background, turning attributes off in the argu-
ments is not useful, though this does not cause an error.

The subcommand scroll can be used with on or off to enabled or disable scrolling of
a window when the cursor would otherwise move below the window due to typing or
output. It can also be used with a positive or negative integer to scroll the win-
dow up or down the given number of lines without changing the current cursor posi-
tion (which therefore appears to move in the opposite direction relative to the
window). In the second case, if scrolling is off it is temporarily turned on to
allow the window to be scrolled.

The subcommand input reads a single character from the window without echoing it
back. If param is supplied the character is assigned to the parameter param, else
it is assigned to the parameter REPLY.

If both param and kparam are supplied, the key is read in `keypad' mode. In this
mode special keys such as function keys and arrow keys return the name of the key
in the parameter kparam. The key names are the macros defined in the curses.h or
ncurses.h with the prefix `KEY_' removed; see also the description of the parameter
zcurses_keycodes below. Other keys cause a value to be set in param as before. On
a successful return only one of param or kparam contains a non-empty string; the
other is set to an empty string.

If mparam is also supplied, input attempts to handle mouse input. This is only
available with the ncurses library; mouse handling can be detected by checking for
the exit status of `zcurses mouse' with no arguments. If a mouse button is clicked
(or double- or triple-clicked, or pressed or released with a configurable delay
from being clicked) then kparam is set to the string MOUSE, and mparam is set to an
array consisting of the following elements:
- An identifier to discriminate different input devices; this is only rarely
useful.
- The x, y and z coordinates of the mouse click relative to the full screen,
as three elements in that order (i.e. the y coordinate is, unusually, after
the x coordinate). The z coordinate is only available for a few unusual in-
put devices and is otherwise set to zero.
- Any events that occurred as separate items; usually there will be just one.
An event consists of PRESSED, RELEASED, CLICKED, DOUBLE_CLICKED or
TRIPLE_CLICKED followed immediately (in the same element) by the number of
the button.
- If the shift key was pressed, the string SHIFT.
- If the control key was pressed, the string CTRL.
- If the alt key was pressed, the string ALT.

Not all mouse events may be passed through to the terminal window; most terminal
emulators handle some mouse events themselves. Note that the ncurses manual im-
plies that using input both with and without mouse handling may cause the mouse
cursor to appear and disappear.

The subcommand mouse can be used to configure the use of the mouse. There is no
window argument; mouse options are global. `zcurses mouse' with no arguments re-
turns status 0 if mouse handling is possible, else status 1. Otherwise, the possi-
ble arguments (which may be combined on the same command line) are as follows. de-
lay num sets the maximum delay in milliseconds between press and release events to
be considered as a click; the value 0 disables click resolution, and the default is
one sixth of a second. motion proceeded by an optional `+' (the default) or -
turns on or off reporting of mouse motion in addition to clicks, presses and re-
leases, which are always reported. However, it appears reports for mouse motion
are not currently implemented.

The subcommand timeout specifies a timeout value for input from targetwin. If int-
val is negative, `zcurses input' waits indefinitely for a character to be typed;
this is the default. If intval is zero, `zcurses input' returns immediately; if
there is typeahead it is returned, else no input is done and status 1 is returned.
If intval is positive, `zcurses input' waits intval milliseconds for input and if
there is none at the end of that period returns status 1.

The subcommand querychar queries the character at the current cursor position. The
return values are stored in the array named param if supplied, else in the array
reply. The first value is the character (which may be a multibyte character if the
system supports them); the second is the color pair in the usual fg_col/bg_col no-
tation, or 0 if color is not supported. Any attributes other than color that apply
to the character, as set with the subcommand attr, appear as additional elements.

The subcommand resize resizes stdscr and all windows to given dimensions (windows
that stick out from the new dimensions are resized down). The underlying curses ex-
tension (resize_term call) can be unavailable. To verify, zeroes can be used for
height and width. If the result of the subcommand is 0, resize_term is available (2
otherwise). Tests show that resizing can be normally accomplished by calling
zcurses end and zcurses refresh. The resize subcommand is provided for versatility.
Multiple system configurations have been checked and zcurses end and zcurses re-
fresh are still needed for correct terminal state after resize. To invoke them with
resize, use endwin argument. Using nosave argument will cause new terminal state
to not be saved internally by zcurses. This is also provided for versatility and
should normally be not needed.

Parameters
ZCURSES_COLORS
Readonly integer. The maximum number of colors the terminal supports. This value
is initialised by the curses library and is not available until the first time
zcurses init is run.

ZCURSES_COLOR_PAIRS
Readonly integer. The maximum number of color pairs fg_col/bg_col that may be de-
fined in `zcurses attr' commands; note this limit applies to all color pairs that
have been used whether or not they are currently active. This value is initialised
by the curses library and is not available until the first time zcurses init is
run.

zcurses_attrs
Readonly array. The attributes supported by zsh/curses; available as soon as the
module is loaded.

zcurses_colors
Readonly array. The colors supported by zsh/curses; available as soon as the mod-
ule is loaded.

zcurses_keycodes
Readonly array. The values that may be returned in the second parameter supplied
to `zcurses input' in the order in which they are defined internally by curses.
Not all function keys are listed, only F0; curses reserves space for F0 up to F63.

zcurses_windows
Readonly array. The current list of windows, i.e. all windows that have been cre-
ated with `zcurses addwin' and not removed with `zcurses delwin'.

THE ZSH/DATETIME MODULE
The zsh/datetime module makes available one builtin command:

strftime [ -s scalar ] format [ epochtime [ nanoseconds ] ]
strftime -r [ -q ] [ -s scalar ] format timestring
Output the date in the format specified. With no epochtime, the current system
date/time is used; optionally, epochtime may be used to specify the number of sec-
onds since the epoch, and nanoseconds may additionally be used to specify the num-
ber of nanoseconds past the second (otherwise that number is assumed to be 0). See
strftime(3) for details. The zsh extensions described in the section EXPANSION OF
PROMPT SEQUENCES in zshmisc(1) are also available.

-q Run quietly; suppress printing of all error messages described below. Er-
rors for invalid epochtime values are always printed.

-r With the option -r (reverse), use format to parse the input string
timestring and output the number of seconds since the epoch at which the
time occurred. The parsing is implemented by the system function strptime;
see strptime(3). This means that zsh format extensions are not available,
but for reverse lookup they are not required.

In most implementations of strftime any timezone in the timestring is ig-
nored and the local timezone declared by the TZ environment variable is
used; other parameters are set to zero if not present.

If timestring does not match format the command returns status 1 and prints
an error message. If timestring matches format but not all characters in
timestring were used, the conversion succeeds but also prints an error mes-
sage.

If either of the system functions strptime or mktime is not available, sta-
tus 2 is returned and an error message is printed.

-s scalar
Assign the date string (or epoch time in seconds if -r is given) to scalar
instead of printing it.

Note that depending on the system's declared integral time type, strftime may pro-
duce incorrect results for epoch times greater than 2147483647 which corresponds to
2038-01-19 03:14:07 +0000.

The zsh/datetime module makes available several parameters; all are readonly:

EPOCHREALTIME
A floating point value representing the number of seconds since the epoch. The no-
tional accuracy is to nanoseconds if the clock_gettime call is available and to mi-
croseconds otherwise, but in practice the range of double precision floating point
and shell scheduling latencies may be significant effects.

EPOCHSECONDS
An integer value representing the number of seconds since the epoch.

epochtime
An array value containing the number of seconds since the epoch in the first ele-
ment and the remainder of the time since the epoch in nanoseconds in the second el-
ement. To ensure the two elements are consistent the array should be copied or
otherwise referenced as a single substitution before the values are used. The fol-
lowing idiom may be used:

for secs nsecs in $epochtime; do
...
done

THE ZSH/DB/GDBM MODULE
The zsh/db/gdbm module is used to create "tied" associative arrays that interface to data-
base files. If the GDBM interface is not available, the builtins defined by this module
will report an error. This module is also intended as a prototype for creating additional
database interfaces, so the ztie builtin may move to a more generic module in the future.

The builtins in this module are:

ztie -d db/gdbm -f filename [ -r ] arrayname
Open the GDBM database identified by filename and, if successful, create the asso-
ciative array arrayname linked to the file. To create a local tied array, the pa-
rameter must first be declared, so commands similar to the following would be exe-
cuted inside a function scope:

local -A sampledb
ztie -d db/gdbm -f sample.gdbm sampledb

The -r option opens the database file for reading only, creating a parameter with
the readonly attribute. Without this option, using `ztie' on a file for which the
user does not have write permission is an error. If writable, the database is
opened synchronously so fields changed in arrayname are immediately written to
filename.

Changes to the file modes filename after it has been opened do not alter the state
of arrayname, but `typeset -r arrayname' works as expected.

zuntie [ -u ] arrayname ...
Close the GDBM database associated with each arrayname and then unset the parame-
ter. The -u option forces an unset of parameters made readonly with `ztie -r'.

This happens automatically if the parameter is explicitly unset or its local scope
(function) ends. Note that a readonly parameter may not be explicitly unset, so
the only way to unset a global parameter created with `ztie -r' is to use `zuntie
-u'.

zgdbmpath parametername
Put path to database file assigned to parametername into REPLY scalar.

zgdbm_tied
Array holding names of all tied parameters.

The fields of an associative array tied to GDBM are neither cached nor otherwise stored in
memory, they are read from or written to the database on each reference. Thus, for exam-
ple, the values in a readonly array may be changed by a second writer of the same database
file.

THE ZSH/DELTOCHAR MODULE
The zsh/deltochar module makes available two ZLE functions:

delete-to-char
Read a character from the keyboard, and delete from the cursor position up to and
including the next (or, with repeat count n, the nth) instance of that character.
Negative repeat counts mean delete backwards.

zap-to-char
This behaves like delete-to-char, except that the final occurrence of the character
itself is not deleted.

THE ZSH/EXAMPLE MODULE
The zsh/example module makes available one builtin command:

example [ -flags ] [ args ... ]
Displays the flags and arguments it is invoked with.

The purpose of the module is to serve as an example of how to write a module.

THE ZSH/FILES MODULE
The zsh/files module makes available some common commands for file manipulation as
builtins; these commands are probably not needed for many normal situations but can be
useful in emergency recovery situations with constrained resources. The commands do not
implement all features now required by relevant standards committees.

For all commands, a variant beginning zf_ is also available and loaded automatically. Us-
ing the features capability of zmodload will let you load only those names you want. Note
that it's possible to load only the builtins with zsh-specific names using the following
command:

zmodload -m -F zsh/files b:zf_\*

The commands loaded by default are:

chgrp [ -hRs ] group filename ...
Changes group of files specified. This is equivalent to chown with a user-spec ar-
gument of `:group'.

chmod [ -Rs ] mode filename ...
Changes mode of files specified.

The specified mode must be in octal.

The -R option causes chmod to recursively descend into directories, changing the
mode of all files in the directory after changing the mode of the directory itself.

The -s option is a zsh extension to chmod functionality. It enables paranoid be-
haviour, intended to avoid security problems involving a chmod being tricked into
affecting files other than the ones intended. It will refuse to follow symbolic
links, so that (for example) ``chmod 600 /tmp/foo/passwd'' can't accidentally chmod
/etc/passwd if /tmp/foo happens to be a link to /etc. It will also check where it
is after leaving directories, so that a recursive chmod of a deep directory tree
can't end up recursively chmoding /usr as a result of directories being moved up
the tree.

chown [ -hRs ] user-spec filename ...
Changes ownership and group of files specified.

The user-spec can be in four forms:

user change owner to user; do not change group
user:: change owner to user; do not change group
user: change owner to user; change group to user's primary group
user:group
change owner to user; change group to group
:group do not change owner; change group to group

In each case, the `:' may instead be a `.'. The rule is that if there is a `:'
then the separator is `:', otherwise if there is a `.' then the separator is `.',
otherwise there is no separator.

Each of user and group may be either a username (or group name, as appropriate) or
a decimal user ID (group ID). Interpretation as a name takes precedence, if there
is an all-numeric username (or group name).

If the target is a symbolic link, the -h option causes chown to set the ownership
of the link instead of its target.

The -R option causes chown to recursively descend into directories, changing the
ownership of all files in the directory after changing the ownership of the direc-
tory itself.

The -s option is a zsh extension to chown functionality. It enables paranoid be-
haviour, intended to avoid security problems involving a chown being tricked into
affecting files other than the ones intended. It will refuse to follow symbolic
links, so that (for example) ``chown luser /tmp/foo/passwd'' can't accidentally
chown /etc/passwd if /tmp/foo happens to be a link to /etc. It will also check
where it is after leaving directories, so that a recursive chown of a deep direc-
tory tree can't end up recursively chowning /usr as a result of directories being
moved up the tree.

ln [ -dfhins ] filename dest
ln [ -dfhins ] filename ... dir
Creates hard (or, with -s, symbolic) links. In the first form, the specified des-
tination is created, as a link to the specified filename. In the second form, each
of the filenames is taken in turn, and linked to a pathname in the specified direc-
tory that has the same last pathname component.

Normally, ln will not attempt to create hard links to directories. This check can
be overridden using the -d option. Typically only the super-user can actually suc-
ceed in creating hard links to directories. This does not apply to symbolic links
in any case.

By default, existing files cannot be replaced by links. The -i option causes the
user to be queried about replacing existing files. The -f option causes existing
files to be silently deleted, without querying. -f takes precedence.

The -h and -n options are identical and both exist for compatibility; either one
indicates that if the target is a symlink then it should not be dereferenced. Typ-
ically this is used in combination with -sf so that if an existing link points to a
directory then it will be removed, instead of followed. If this option is used
with multiple filenames and the target is a symbolic link pointing to a directory
then the result is an error.

mkdir [ -p ] [ -m mode ] dir ...
Creates directories. With the -p option, non-existing parent directories are first
created if necessary, and there will be no complaint if the directory already ex-
ists. The -m option can be used to specify (in octal) a set of file permissions
for the created directories, otherwise mode 777 modified by the current umask (see
umask(2)) is used.

mv [ -fi ] filename dest
mv [ -fi ] filename ... dir
Moves files. In the first form, the specified filename is moved to the specified
destination. In the second form, each of the filenames is taken in turn, and moved
to a pathname in the specified directory that has the same last pathname component.

By default, the user will be queried before replacing any file that the user cannot
write to, but writable files will be silently removed. The -i option causes the
user to be queried about replacing any existing files. The -f option causes any
existing files to be silently deleted, without querying. -f takes precedence.

Note that this mv will not move files across devices. Historical versions of mv,
when actual renaming is impossible, fall back on copying and removing files; if
this behaviour is desired, use cp and rm manually. This may change in a future
version.

rm [ -dfiRrs ] filename ...
Removes files and directories specified.

Normally, rm will not remove directories (except with the -R or -r options). The
-d option causes rm to try removing directories with unlink (see unlink(2)), the
same method used for files. Typically only the super-user can actually succeed in
unlinking directories in this way. -d takes precedence over -R and -r.

By default, the user will be queried before removing any file that the user cannot
write to, but writable files will be silently removed. The -i option causes the
user to be queried about removing any files. The -f option causes files to be
silently deleted, without querying, and suppresses all error indications. -f takes
precedence.

The -R and -r options cause rm to recursively descend into directories, deleting
all files in the directory before removing the directory with the rmdir system call
(see rmdir(2)).

The -s option is a zsh extension to rm functionality. It enables paranoid behav-
iour, intended to avoid common security problems involving a root-run rm being
tricked into removing files other than the ones intended. It will refuse to follow
symbolic links, so that (for example) ``rm /tmp/foo/passwd'' can't accidentally re-
move /etc/passwd if /tmp/foo happens to be a link to /etc. It will also check
where it is after leaving directories, so that a recursive removal of a deep direc-
tory tree can't end up recursively removing /usr as a result of directories being
moved up the tree.

rmdir dir ...
Removes empty directories specified.

sync Calls the system call of the same name (see sync(2)), which flushes dirty buffers
to disk. It might return before the I/O has actually been completed.

THE ZSH/LANGINFO MODULE
The zsh/langinfo module makes available one parameter:

langinfo
An associative array that maps langinfo elements to their values.

Your implementation may support a number of the following keys:

CODESET, D_T_FMT, D_FMT, T_FMT, RADIXCHAR, THOUSEP, YESEXPR, NOEXPR, CRNCYSTR, AB-
DAY_{1..7}, DAY_{1..7}, ABMON_{1..12}, MON_{1..12}, T_FMT_AMPM, AM_STR, PM_STR,
ERA, ERA_D_FMT, ERA_D_T_FMT, ERA_T_FMT, ALT_DIGITS

THE ZSH/MAPFILE MODULE
The zsh/mapfile module provides one special associative array parameter of the same name.

mapfile
This associative array takes as keys the names of files; the resulting value is the
content of the file. The value is treated identically to any other text coming
from a parameter. The value may also be assigned to, in which case the file in
question is written (whether or not it originally existed); or an element may be
unset, which will delete the file in question. For example, `vared mapfile[my-
file]' works as expected, editing the file `myfile'.

When the array is accessed as a whole, the keys are the names of files in the cur-
rent directory, and the values are empty (to save a huge overhead in memory). Thus
${(k)mapfile} has the same effect as the glob operator *(D), since files beginning
with a dot are not special. Care must be taken with expressions such as rm
${(k)mapfile}, which will delete every file in the current directory without the
usual `rm *' test.

The parameter mapfile may be made read-only; in that case, files referenced may not
be written or deleted.

A file may conveniently be read into an array as one line per element with the form
`array=("${(f@)mapfile[filename]}")'. The double quotes and the `@' are necessary
to prevent empty lines from being removed. Note that if the file ends with a new-
line, the shell will split on the final newline, generating an additional empty
field; this can be suppressed by using `array=("${(f@)${mapfile[file-
name]%$'\n'}}")'.

Limitations
Although reading and writing of the file in question is efficiently handled, zsh's inter-
nal memory management may be arbitrarily baroque; however, mapfile is usually very much
more efficient than anything involving a loop. Note in particular that the whole contents
of the file will always reside physically in memory when accessed (possibly multiple
times, due to standard parameter substitution operations). In particular, this means han-
dling of sufficiently long files (greater than the machine's swap space, or than the range
of the pointer type) will be incorrect.

No errors are printed or flagged for non-existent, unreadable, or unwritable files, as the
parameter mechanism is too low in the shell execution hierarchy to make this convenient.

It is unfortunate that the mechanism for loading modules does not yet allow the user to
specify the name of the shell parameter to be given the special behaviour.

THE ZSH/MATHFUNC MODULE
The zsh/mathfunc module provides standard mathematical functions for use when evaluating
mathematical formulae. The syntax agrees with normal C and FORTRAN conventions, for exam-
ple,

(( f = sin(0.3) ))

assigns the sine of 0.3 to the parameter f.

Most functions take floating point arguments and return a floating point value. However,
any necessary conversions from or to integer type will be performed automatically by the
shell. Apart from atan with a second argument and the abs, int and float functions, all
functions behave as noted in the manual page for the corresponding C function, except that
any arguments out of range for the function in question will be detected by the shell and
an error reported.

The following functions take a single floating point argument: acos, acosh, asin, asinh,
atan, atanh, cbrt, ceil, cos, cosh, erf, erfc, exp, expm1, fabs, floor, gamma, j0, j1,
lgamma, log, log10, log1p, log2, logb, sin, sinh, sqrt, tan, tanh, y0, y1. The atan func-
tion can optionally take a second argument, in which case it behaves like the C function
atan2. The ilogb function takes a single floating point argument, but returns an integer.

The function signgam takes no arguments, and returns an integer, which is the C variable
of the same name, as described in gamma(3). Note that it is therefore only useful immedi-
ately after a call to gamma or lgamma. Note also that `signgam()' and `signgam' are dis-
tinct expressions.

The functions min, max, and sum are defined not in this module but in the zmathfunc au-
toloadable function, described in the section `Mathematical Functions' in zshcontrib(1).

The following functions take two floating point arguments: copysign, fmod, hypot,
nextafter.

The following take an integer first argument and a floating point second argument: jn, yn.

The following take a floating point first argument and an integer second argument: ldexp,
scalb.

The function abs does not convert the type of its single argument; it returns the absolute
value of either a floating point number or an integer. The functions float and int con-
vert their arguments into a floating point or integer value (by truncation) respectively.

Note that the C pow function is available in ordinary math evaluation as the `**' operator
and is not provided here.

The function rand48 is available if your system's mathematical library has the function
erand48(3). It returns a pseudo-random floating point number between 0 and 1. It takes a
single string optional argument.

If the argument is not present, the random number seed is initialised by three calls to
the rand(3) function --- this produces the same random numbers as the next three values of
$RANDOM.

If the argument is present, it gives the name of a scalar parameter where the current ran-
dom number seed will be stored. On the first call, the value must contain at least twelve
hexadecimal digits (the remainder of the string is ignored), or the seed will be ini-
tialised in the same manner as for a call to rand48 with no argument. Subsequent calls to
rand48(param) will then maintain the seed in the parameter param as a string of twelve
hexadecimal digits, with no base signifier. The random number sequences for different pa-
rameters are completely independent, and are also independent from that used by calls to
rand48 with no argument.

For example, consider

print $(( rand48(seed) ))
print $(( rand48() ))
print $(( rand48(seed) ))

Assuming $seed does not exist, it will be initialised by the first call. In the second
call, the default seed is initialised; note, however, that because of the properties of
rand() there is a correlation between the seeds used for the two initialisations, so for
more secure uses, you should generate your own 12-byte seed. The third call returns to
the same sequence of random numbers used in the first call, unaffected by the intervening
rand48().

THE ZSH/NEARCOLOR MODULE
The zsh/nearcolor module replaces colours specified as hex triplets with the nearest
colour in the 88 or 256 colour palettes that are widely used by terminal emulators. By
default, 24-bit true colour escape codes are generated when colours are specified using
hex triplets. These are not supported by all terminals. The purpose of this module is to
make it easier to define colour preferences in a form that can work across a range of ter-
minal emulators.

Aside from the default colour, the ANSI standard for terminal escape codes provides for
eight colours. The bright attribute brings this to sixteen. These basic colours are com-
monly used in terminal applications due to being widely supported. Expanded 88 and 256
colour palettes are also common and, while the first sixteen colours vary somewhat between
terminals and configurations, these add a generally consistent and predictable set of
colours.

In order to use the zsh/nearcolor module, it only needs to be loaded. Thereafter, whenever
a colour is specified using a hex triplet, it will be compared against each of the avail-
able colours and the closest will be selected. The first sixteen colours are never matched
in this process due to being unpredictable.

It isn't possible to reliably detect support for true colour in the terminal emulator. It
is therefore recommended to be selective in loading the zsh/nearcolor module. For example,
the following checks the COLORTERM environment variable:

[[ $COLORTERM = *(24bit|truecolor)* ]] || zmodload zsh/nearcolor

Note that some terminals accept the true color escape codes but map them internally to a
more limited palette in a similar manner to the zsh/nearcolor module.

THE ZSH/NEWUSER MODULE
The zsh/newuser module is loaded at boot if it is available, the RCS option is set, and
the PRIVILEGED option is not set (all three are true by default). This takes place imme-
diately after commands in the global zshenv file (typically /etc/zsh/zshenv), if any, have
been executed. If the module is not available it is silently ignored by the shell; the
module may safely be removed from $MODULE_PATH by the administrator if it is not required.

On loading, the module tests if any of the start-up files .zshenv, .zprofile, .zshrc or
.zlogin exist in the directory given by the environment variable ZDOTDIR, or the user's
home directory if that is not set. The test is not performed and the module halts pro-
cessing if the shell was in an emulation mode (i.e. had been invoked as some other shell
than zsh).

If none of the start-up files were found, the module then looks for the file newuser first
in a sitewide directory, usually the parent directory of the site-functions directory, and
if that is not found the module searches in a version-specific directory, usually the par-
ent of the functions directory containing version-specific functions. (These directories
can be configured when zsh is built using the --enable-site-scriptdir=dir and --en-
able-scriptdir=dir flags to configure, respectively; the defaults are prefix/share/zsh and
prefix/share/zsh/$ZSH_VERSION where the default prefix is /usr/local.)

If the file newuser is found, it is then sourced in the same manner as a start-up file.
The file is expected to contain code to install start-up files for the user, however any
valid shell code will be executed.

The zsh/newuser module is then unconditionally unloaded.

Note that it is possible to achieve exactly the same effect as the zsh/newuser module by
adding code to /etc/zsh/zshenv. The module exists simply to allow the shell to make ar-
rangements for new users without the need for intervention by package maintainers and sys-
tem administrators.

The script supplied with the module invokes the shell function zsh-newuser-install. This
may be invoked directly by the user even if the zsh/newuser module is disabled. Note,
however, that if the module is not installed the function will not be installed either.
The function is documented in the section User Configuration Functions in zshcontrib(1).

THE ZSH/PARAMETER MODULE
The zsh/parameter module gives access to some of the internal hash tables used by the
shell by defining some special parameters.

options
The keys for this associative array are the names of the options that can be set
and unset using the setopt and unsetopt builtins. The value of each key is either
the string on if the option is currently set, or the string off if the option is
unset. Setting a key to one of these strings is like setting or unsetting the op-
tion, respectively. Unsetting a key in this array is like setting it to the value
off.

commands
This array gives access to the command hash table. The keys are the names of exter-
nal commands, the values are the pathnames of the files that would be executed when
the command would be invoked. Setting a key in this array defines a new entry in
this table in the same way as with the hash builtin. Unsetting a key as in `unset
"commands[foo]"' removes the entry for the given key from the command hash table.

functions
This associative array maps names of enabled functions to their definitions. Set-
ting a key in it is like defining a function with the name given by the key and the
body given by the value. Unsetting a key removes the definition for the function
named by the key.

dis_functions
Like functions but for disabled functions.

functions_source
This readonly associative array maps names of enabled functions to the name of the
file containing the source of the function.

For an autoloaded function that has already been loaded, or marked for autoload
with an absolute path, or that has had its path resolved with `functions -r', this
is the file found for autoloading, resolved to an absolute path.

For a function defined within the body of a script or sourced file, this is the
name of that file. In this case, this is the exact path originally used to that
file, which may be a relative path.

For any other function, including any defined at an interactive prompt or an au-
toload function whose path has not yet been resolved, this is the empty string.
However, the hash element is reported as defined just so long as the function is
present: the keys to this hash are the same as those to $functions.

dis_functions_source
Like functions_source but for disabled functions.

builtins
This associative array gives information about the builtin commands currently en-
abled. The keys are the names of the builtin commands and the values are either
`undefined' for builtin commands that will automatically be loaded from a module if
invoked or `defined' for builtin commands that are already loaded.

dis_builtins
Like builtins but for disabled builtin commands.

reswords
This array contains the enabled reserved words.

dis_reswords
Like reswords but for disabled reserved words.

patchars
This array contains the enabled pattern characters.

dis_patchars
Like patchars but for disabled pattern characters.

aliases
This maps the names of the regular aliases currently enabled to their expansions.

dis_aliases
Like aliases but for disabled regular aliases.

galiases
Like aliases, but for global aliases.

dis_galiases
Like galiases but for disabled global aliases.

saliases
Like raliases, but for suffix aliases.

dis_saliases
Like saliases but for disabled suffix aliases.

parameters
The keys in this associative array are the names of the parameters currently de-
fined. The values are strings describing the type of the parameter, in the same
format used by the t parameter flag, see zshexpn(1) . Setting or unsetting keys in
this array is not possible.

modules
An associative array giving information about modules. The keys are the names of
the modules loaded, registered to be autoloaded, or aliased. The value says which
state the named module is in and is one of the strings `loaded', `autoloaded', or
`alias:name', where name is the name the module is aliased to.

Setting or unsetting keys in this array is not possible.

dirstack
A normal array holding the elements of the directory stack. Note that the output of
the dirs builtin command includes one more directory, the current working direc-
tory.

history
This associative array maps history event numbers to the full history lines. Al-
though it is presented as an associative array, the array of all values (${his-
tory[@]}) is guaranteed to be returned in order from most recent to oldest history
event, that is, by decreasing history event number.

historywords
A special array containing the words stored in the history. These also appear in
most to least recent order.

jobdirs
This associative array maps job numbers to the directories from which the job was
started (which may not be the current directory of the job).

The keys of the associative arrays are usually valid job numbers, and these are the
values output with, for example, ${(k)jobdirs}. Non-numeric job references may be
used when looking up a value; for example, ${jobdirs[%+]} refers to the current
job.

jobtexts
This associative array maps job numbers to the texts of the command lines that were
used to start the jobs.

Handling of the keys of the associative array is as described for jobdirs above.

jobstates
This associative array gives information about the states of the jobs currently
known. The keys are the job numbers and the values are strings of the form
`job-state:mark:pid=state...'. The job-state gives the state the whole job is cur-
rently in, one of `running', `suspended', or `done'. The mark is `+' for the cur-
rent job, `-' for the previous job and empty otherwise. This is followed by one
`:pid=state' for every process in the job. The pids are, of course, the process IDs
and the state describes the state of that process.

Handling of the keys of the associative array is as described for jobdirs above.

nameddirs
This associative array maps the names of named directories to the pathnames they
stand for.

userdirs
This associative array maps user names to the pathnames of their home directories.

usergroups
This associative array maps names of system groups of which the current user is a
member to the corresponding group identifiers. The contents are the same as the
groups output by the id command.

funcfiletrace
This array contains the absolute line numbers and corresponding file names for the
point where the current function, sourced file, or (if EVAL_LINENO is set) eval
command was called. The array is of the same length as funcsourcetrace and func-
trace, but differs from funcsourcetrace in that the line and file are the point of
call, not the point of definition, and differs from functrace in that all values
are absolute line numbers in files, rather than relative to the start of a func-
tion, if any.

funcsourcetrace
This array contains the file names and line numbers of the points where the func-
tions, sourced files, and (if EVAL_LINENO is set) eval commands currently being ex-
ecuted were defined. The line number is the line where the `function name' or
`name ()' started. In the case of an autoloaded function the line number is re-
ported as zero. The format of each element is filename:lineno.

For functions autoloaded from a file in native zsh format, where only the body of
the function occurs in the file, or for files that have been executed by the source
or `.' builtins, the trace information is shown as filename:0, since the entire
file is the definition. The source file name is resolved to an absolute path when
the function is loaded or the path to it otherwise resolved.

Most users will be interested in the information in the funcfiletrace array in-
stead.

funcstack
This array contains the names of the functions, sourced files, and (if EVAL_LINENO
is set) eval commands. currently being executed. The first element is the name of
the function using the parameter.

The standard shell array zsh_eval_context can be used to determine the type of
shell construct being executed at each depth: note, however, that is in the oppo-
site order, with the most recent item last, and it is more detailed, for example
including an entry for toplevel, the main shell code being executed either interac-
tively or from a script, which is not present in $funcstack.

functrace
This array contains the names and line numbers of the callers corresponding to the
functions currently being executed. The format of each element is name:lineno.
Callers are also shown for sourced files; the caller is the point where the source
or `.' command was executed.

THE ZSH/PCRE MODULE
The zsh/pcre module makes some commands available as builtins:

pcre_compile [ -aimxs ] PCRE
Compiles a perl-compatible regular expression.

Option -a will force the pattern to be anchored. Option -i will compile a case-in-
sensitive pattern. Option -m will compile a multi-line pattern; that is, ^ and $
will match newlines within the pattern. Option -x will compile an extended pat-
tern, wherein whitespace and # comments are ignored. Option -s makes the dot
metacharacter match all characters, including those that indicate newline.

pcre_study
Studies the previously-compiled PCRE which may result in faster matching.

pcre_match [ -v var ] [ -a arr ] [ -n offset ] [ -b ] string
Returns successfully if string matches the previously-compiled PCRE.

Upon successful match, if the expression captures substrings within parentheses,
pcre_match will set the array match to those substrings, unless the -a option is
given, in which case it will set the array arr. Similarly, the variable MATCH will
be set to the entire matched portion of the string, unless the -v option is given,
in which case the variable var will be set. No variables are altered if there is
no successful match. A -n option starts searching for a match from the byte offset
position in string. If the -b option is given, the variable ZPCRE_OP will be set
to an offset pair string, representing the byte offset positions of the entire
matched portion within the string. For example, a ZPCRE_OP set to "32 45" indi-
cates that the matched portion began on byte offset 32 and ended on byte offset 44.
Here, byte offset position 45 is the position directly after the matched portion.
Keep in mind that the byte position isn't necessarily the same as the character po-
sition when UTF-8 characters are involved. Consequently, the byte offset positions
are only to be relied on in the context of using them for subsequent searches on
string, using an offset position as an argument to the -n option. This is mostly
used to implement the "find all non-overlapping matches" functionality.

A simple example of "find all non-overlapping matches":

string="The following zip codes: 78884 90210 99513"
pcre_compile -m "\d{5}"
accum=()
pcre_match -b -- $string
while [[ $? -eq 0 ]] do
b=($=ZPCRE_OP)
accum+=$MATCH
pcre_match -b -n $b[2] -- $string
done
print -l $accum

The zsh/pcre module makes available the following test condition:

expr -pcre-match pcre
Matches a string against a perl-compatible regular expression.

For example,

[[ "$text" -pcre-match ^d+$ ]] &&
print text variable contains only "d's".

If the REMATCH_PCRE option is set, the =~ operator is equivalent to -pcre-match,
and the NO_CASE_MATCH option may be used. Note that NO_CASE_MATCH never applies to
the pcre_match builtin, instead use the -i switch of pcre_compile.

THE ZSH/PARAM/PRIVATE MODULE
The zsh/param/private module is used to create parameters whose scope is limited to the
current function body, and not to other functions called by the current function.

This module provides a single autoloaded builtin:

private [ {+|-}AHUahlprtux ] [ {+|-}EFLRZi [ n ] ] [ name[=value] ... ]
The private builtin accepts all the same options and arguments as local (zsh-
builtins(1)) except for the `-T' option. Tied parameters may not be made private.

If used at the top level (outside a function scope), private creates a normal pa-
rameter in the same manner as declare or typeset. A warning about this is printed
if WARN_CREATE_GLOBAL is set (zshoptions(1)). Used inside a function scope, pri-
vate creates a local parameter similar to one declared with local, except having
special properties noted below.

Special parameters which expose or manipulate internal shell state, such as ARGC,
argv, COLUMNS, LINES, UID, EUID, IFS, PROMPT, RANDOM, SECONDS, etc., cannot be made
private unless the `-h' option is used to hide the special meaning of the parame-
ter. This may change in the future.

As with other typeset equivalents, private is both a builtin and a reserved word, so ar-
rays may be assigned with parenthesized word list name=(value...) syntax. However, the
reserved word `private' is not available until zsh/param/private is loaded, so care must
be taken with order of execution and parsing for function definitions which use private.
To compensate for this, the module also adds the option `-P' to the `local' builtin to de-
clare private parameters.

For example, this construction fails if zsh/param/private has not yet been loaded when
`bad_declaration' is defined:
bad_declaration() {
zmodload zsh/param/private
private array=( one two three )
}

This construction works because local is already a keyword, and the module is loaded be-
fore the statement is executed:
good_declaration() {
zmodload zsh/param/private
local -P array=( one two three )
}

The following is usable in scripts but may have trouble with autoload:
zmodload zsh/param/private
iffy_declaration() {
private array=( one two three )
}

The private builtin may always be used with scalar assignments and for declarations with-
out assignments.

Parameters declared with private have the following properties:

o Within the function body where it is declared, the parameter behaves as a local,
except as noted above for tied or special parameters.

o The type of a parameter declared private cannot be changed in the scope where it
was declared, even if the parameter is unset. Thus an array cannot be assigned to
a private scalar, etc.

o Within any other function called by the declaring function, the private parameter
does NOT hide other parameters of the same name, so for example a global parameter
of the same name is visible and may be assigned or unset. This includes calls to
anonymous functions, although that may also change in the future.

o An exported private remains in the environment of inner scopes but appears unset
for the current shell in those scopes. Generally, exporting private parameters
should be avoided.

Note that this differs from the static scope defined by compiled languages derived from C,
in that the a new call to the same function creates a new scope, i.e., the parameter is
still associated with the call stack rather than with the function definition. It differs
from ksh `typeset -S' because the syntax used to define the function has no bearing on
whether the parameter scope is respected.

THE ZSH/REGEX MODULE
The zsh/regex module makes available the following test condition:

expr -regex-match regex
Matches a string against a POSIX extended regular expression. On successful match,
matched portion of the string will normally be placed in the MATCH variable. If
there are any capturing parentheses within the regex, then the match array variable
will contain those. If the match is not successful, then the variables will not be
altered.

For example,

[[ alphabetical -regex-match ^a([^a]+)a([^a]+)a ]] &&
print -l $MATCH X $match

If the option REMATCH_PCRE is not set, then the =~ operator will automatically load
this module as needed and will invoke the -regex-match operator.

If BASH_REMATCH is set, then the array BASH_REMATCH will be set instead of MATCH
and match.

THE ZSH/SCHED MODULE
The zsh/sched module makes available one builtin command and one parameter.

sched [-o] [+]hh:mm[:ss] command ...
sched [-o] [+]seconds command ...
sched [ -item ]
Make an entry in the scheduled list of commands to execute. The time may be speci-
fied in either absolute or relative time, and either as hours, minutes and (option-
ally) seconds separated by a colon, or seconds alone. An absolute number of sec-
onds indicates the time since the epoch (1970/01/01 00:00); this is useful in com-
bination with the features in the zsh/datetime module, see the zsh/datetime module
entry in zshmodules(1).

With no arguments, prints the list of scheduled commands. If the scheduled command
has the -o flag set, this is shown at the start of the command.

With the argument `-item', removes the given item from the list. The numbering of
the list is continuous and entries are in time order, so the numbering can change
when entries are added or deleted.

Commands are executed either immediately before a prompt, or while the shell's line
editor is waiting for input. In the latter case it is useful to be able to produce
output that does not interfere with the line being edited. Providing the option -o
causes the shell to clear the command line before the event and redraw it after-
wards. This should be used with any scheduled event that produces visible output
to the terminal; it is not needed, for example, with output that updates a terminal
emulator's title bar.

To effect changes to the editor buffer when an event executes, use the `zle' com-
mand with no arguments to test whether the editor is active, and if it is, then use
`zle widget' to access the editor via the named widget.

The sched builtin 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/sched b:sched'.

zsh_scheduled_events
A readonly array corresponding to the events scheduled by the sched builtin. The
indices of the array correspond to the numbers shown when sched is run with no ar-
guments (provided that the KSH_ARRAYS option is not set). The value of the array
consists of the scheduled time in seconds since the epoch (see the section `The
zsh/datetime Module' for facilities for using this number), followed by a colon,
followed by any options (which may be empty but will be preceded by a `-' other-
wise), followed by a colon, followed by the command to be executed.

The sched builtin should be used for manipulating the events. Note that this will
have an immediate effect on the contents of the array, so that indices may become
invalid.

THE ZSH/NET/SOCKET MODULE
The zsh/net/socket module makes available one builtin command:

zsocket [ -altv ] [ -d fd ] [ args ]
zsocket is implemented as a builtin to allow full use of shell command line edit-
ing, file I/O, and job control mechanisms.

Outbound Connections
zsocket [ -v ] [ -d fd ] filename
Open a new Unix domain connection to filename. The shell parameter REPLY will be
set to the file descriptor associated with that connection. Currently, only stream
connections are supported.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

File descriptors can be closed with normal shell syntax when no longer needed, for
example:

exec {REPLY}>&-

Inbound Connections
zsocket -l [ -v ] [ -d fd ] filename
zsocket -l will open a socket listening on filename. The shell parameter REPLY
will be set to the file descriptor associated with that listener. The file de-
scriptor remains open in subshells and forked external executables.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

zsocket -a [ -tv ] [ -d targetfd ] listenfd
zsocket -a will accept an incoming connection to the socket associated with lis-
tenfd. The shell parameter REPLY will be set to the file descriptor associated
with the inbound connection. The file descriptor remains open in subshells and
forked external executables.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

If -t is specified, zsocket will return if no incoming connection is pending. Oth-
erwise it will wait for one.

In order to elicit more verbose output, use -v.

THE ZSH/STAT MODULE
The zsh/stat module makes available one builtin command under two possible names:

zstat [ -gnNolLtTrs ] [ -f fd ] [ -H hash ] [ -A array ] [ -F fmt ]
[ +element ] [ file ... ]
stat ...
The command acts as a front end to the stat system call (see stat(2)). The same
command is provided with two names; as the name stat is often used by an external
command it is recommended that only the zstat form of the command is used. This
can be arranged by loading the module with the command `zmodload -F zsh/stat b:zs-
tat'.

If the stat call fails, the appropriate system error message printed and status 1
is returned. The fields of struct stat give information about the files provided
as arguments to the command. In addition to those available from the stat call, an
extra element `link' is provided. These elements are:

device The number of the device on which the file resides.

inode The unique number of the file on this device (`inode' number).

mode The mode of the file; that is, the file's type and access permissions. With
the -s option, this will be returned as a string corresponding to the first
column in the display of the ls -l command.

nlink The number of hard links to the file.

uid The user ID of the owner of the file. With the -s option, this is displayed
as a user name.

gid The group ID of the file. With the -s option, this is displayed as a group
name.

rdev The raw device number. This is only useful for special devices.

size The size of the file in bytes.

atime
mtime
ctime The last access, modification and inode change times of the file, respec-
tively, as the number of seconds since midnight GMT on 1st January, 1970.
With the -s option, these are printed as strings for the local time zone;
the format can be altered with the -F option, and with the -g option the
times are in GMT.

blksize
The number of bytes in one allocation block on the device on which the file
resides.

block The number of disk blocks used by the file.

link If the file is a link and the -L option is in effect, this contains the name
of the file linked to, otherwise it is empty. Note that if this element is
selected (``zstat +link'') then the -L option is automatically used.

A particular element may be selected by including its name preceded by a `+' in the
option list; only one element is allowed. The element may be shortened to any
unique set of leading characters. Otherwise, all elements will be shown for all
files.

Options:

-A array
Instead of displaying the results on standard output, assign them to an ar-
ray, one struct stat element per array element for each file in order. In
this case neither the name of the element nor the name of the files appears
in array unless the -t or -n options were given, respectively. If -t is
given, the element name appears as a prefix to the appropriate array ele-
ment; if -n is given, the file name appears as a separate array element pre-
ceding all the others. Other formatting options are respected.

-H hash
Similar to -A, but instead assign the values to hash. The keys are the ele-
ments listed above. If the -n option is provided then the name of the file
is included in the hash with key name.

-f fd Use the file on file descriptor fd instead of named files; no list of file
names is allowed in this case.

-F fmt Supplies a strftime (see strftime(3)) string for the formatting of the time
elements. The format string supports all of the zsh extensions described in
the section EXPANSION OF PROMPT SEQUENCES in zshmisc(1). The -s option is
implied.

-g Show the time elements in the GMT time zone. The -s option is implied.

-l List the names of the type elements (to standard output or an array as ap-
propriate) and return immediately; arguments, and options other than -A, are
ignored.

-L Perform an lstat (see lstat(2)) rather than a stat system call. In this
case, if the file is a link, information about the link itself rather than
the target file is returned. This option is required to make the link ele-
ment useful. It's important to note that this is the exact opposite from
ls(1), etc.

-n Always show the names of files. Usually these are only shown when output is
to standard output and there is more than one file in the list.

-N Never show the names of files.

-o If a raw file mode is printed, show it in octal, which is more useful for
human consumption than the default of decimal. A leading zero will be
printed in this case. Note that this does not affect whether a raw or for-
matted file mode is shown, which is controlled by the -r and -s options, nor
whether a mode is shown at all.

-r Print raw data (the default format) alongside string data (the -s format);
the string data appears in parentheses after the raw data.

-s Print mode, uid, gid and the three time elements as strings instead of num-
bers. In each case the format is like that of ls -l.

-t Always show the type names for the elements of struct stat. Usually these
are only shown when output is to standard output and no individual element
has been selected.

-T Never show the type names of the struct stat elements.

THE ZSH/SYSTEM MODULE
The zsh/system module makes available various builtin commands and parameters.

Builtins
syserror [ -e errvar ] [ -p prefix ] [ errno | errname ]
This command prints out the error message associated with errno, a system error
number, followed by a newline to standard error.

Instead of the error number, a name errname, for example ENOENT, may be used. The
set of names is the same as the contents of the array errnos, see below.

If the string prefix is given, it is printed in front of the error message, with no
intervening space.

If errvar is supplied, the entire message, without a newline, is assigned to the
parameter names errvar and nothing is output.

A return status of 0 indicates the message was successfully printed (although it
may not be useful if the error number was out of the system's range), a return sta-
tus of 1 indicates an error in the parameters, and a return status of 2 indicates
the error name was not recognised (no message is printed for this).

sysopen [ -arw ] [ -m permissions ] [ -o options ]
-u fd file
This command opens a file. The -r, -w and -a flags indicate whether the file should
be opened for reading, writing and appending, respectively. The -m option allows
the initial permissions to use when creating a file to be specified in octal form.
The file descriptor is specified with -u. Either an explicit file descriptor in the
range 0 to 9 can be specified or a variable name can be given to which the file de-
scriptor number will be assigned.

The -o option allows various system specific options to be specified as a
comma-separated list. The following is a list of possible options. Note that, de-
pending on the system, some may not be available.
cloexec
mark file to be closed when other programs are executed (else the file de-
scriptor remains open in subshells and forked external executables)

create
creat create file if it does not exist

excl create file, error if it already exists

noatime
suppress updating of the file atime

nofollow
fail if file is a symbolic link

sync request that writes wait until data has been physically written

truncate
trunc truncate file to size 0

To close the file, use one of the following:

exec {fd}<&-
exec {fd}>&-

sysread [ -c countvar ] [ -i infd ] [ -o outfd ]
[ -s bufsize ] [ -t timeout ] [ param ]
Perform a single system read from file descriptor infd, or zero if that is not
given. The result of the read is stored in param or REPLY if that is not given.
If countvar is given, the number of bytes read is assigned to the parameter named
by countvar.

The maximum number of bytes read is bufsize or 8192 if that is not given, however
the command returns as soon as any number of bytes was successfully read.

If timeout is given, it specifies a timeout in seconds, which may be zero to poll
the file descriptor. This is handled by the poll system call if available, other-
wise the select system call if available.

If outfd is given, an attempt is made to write all the bytes just read to the file
descriptor outfd. If this fails, because of a system error other than EINTR or be-
cause of an internal zsh error during an interrupt, the bytes read but not written
are stored in the parameter named by param if supplied (no default is used in this
case), and the number of bytes read but not written is stored in the parameter
named by countvar if that is supplied. If it was successful, countvar contains the
full number of bytes transferred, as usual, and param is not set.

The error EINTR (interrupted system call) is handled internally so that shell in-
terrupts are transparent to the caller. Any other error causes a return.

The possible return statuses are
0 At least one byte of data was successfully read and, if appropriate, writ-
ten.

1 There was an error in the parameters to the command. This is the only error
for which a message is printed to standard error.

2 There was an error on the read, or on polling the input file descriptor for
a timeout. The parameter ERRNO gives the error.

3 Data were successfully read, but there was an error writing them to outfd.
The parameter ERRNO gives the error.

4 The attempt to read timed out. Note this does not set ERRNO as this is not
a system error.

5 No system error occurred, but zero bytes were read. This usually indicates
end of file. The parameters are set according to the usual rules; no write
to outfd is attempted.

sysseek [ -u fd ] [ -w start|end|current ] offset
The current file position at which future reads and writes will take place is ad-
justed to the specified byte offset. The offset is evaluated as a math expression.
The -u option allows the file descriptor to be specified. By default the offset is
specified relative to the start or the file but, with the -w option, it is possible
to specify that the offset should be relative to the current position or the end of
the file.

syswrite [ -c countvar ] [ -o outfd ] data
The data (a single string of bytes) are written to the file descriptor outfd, or 1
if that is not given, using the write system call. Multiple write operations may
be used if the first does not write all the data.

If countvar is given, the number of byte written is stored in the parameter named
by countvar; this may not be the full length of data if an error occurred.

The error EINTR (interrupted system call) is handled internally by retrying; other-
wise an error causes the command to return. For example, if the file descriptor is
set to non-blocking output, an error EAGAIN (on some systems, EWOULDBLOCK) may re-
sult in the command returning early.

The return status may be 0 for success, 1 for an error in the parameters to the
command, or 2 for an error on the write; no error message is printed in the last
case, but the parameter ERRNO will reflect the error that occurred.

zsystem flock [ -t timeout ] [ -f var ] [-er] file
zsystem flock -u fd_expr
The builtin zsystem's subcommand flock performs advisory file locking (via the fc-
ntl(2) system call) over the entire contents of the given file. This form of lock-
ing requires the processes accessing the file to cooperate; its most obvious use is
between two instances of the shell itself.

In the first form the named file, which must already exist, is locked by opening a
file descriptor to the file and applying a lock to the file descriptor. The lock
terminates when the shell process that created the lock exits; it is therefore of-
ten convenient to create file locks within subshells, since the lock is automati-
cally released when the subshell exits. Note that use of the print builtin with
the -u option will, as a side effect, release the lock, as will redirection to the
file in the shell holding the lock. To work around this use a subshell, e.g.
`(print message) >> file'. Status 0 is returned if the lock succeeds, else status
1.

In the second form the file descriptor given by the arithmetic expression fd_expr
is closed, releasing a lock. The file descriptor can be queried by using the `-f
var' form during the lock; on a successful lock, the shell variable var is set to
the file descriptor used for locking. The lock will be released if the file de-
scriptor is closed by any other means, for example using `exec {var}>&-'; however,
the form described here performs a safety check that the file descriptor is in use
for file locking.

By default the shell waits indefinitely for the lock to succeed. The option -t
timeout specifies a timeout for the lock in seconds; currently this must be an in-
teger. The shell will attempt to lock the file once a second during this period.
If the attempt times out, status 2 is returned.

If the option -e is given, the file descriptor for the lock is preserved when the
shell uses exec to start a new process; otherwise it is closed at that point and
the lock released.

If the option -r is given, the lock is only for reading, otherwise it is for read-
ing and writing. The file descriptor is opened accordingly.

zsystem supports subcommand
The builtin zsystem's subcommand supports tests whether a given subcommand is sup-
ported. It returns status 0 if so, else status 1. It operates silently unless
there was a syntax error (i.e. the wrong number of arguments), in which case status
255 is returned. Status 1 can indicate one of two things: subcommand is known but
not supported by the current operating system, or subcommand is not known (possibly
because this is an older version of the shell before it was implemented).

Math Functions
systell(fd)
The systell math function returns the current file position for the file descriptor
passed as an argument.

Parameters
errnos A readonly array of the names of errors defined on the system. These are typically
macros defined in C by including the system header file errno.h. The index of each
name (assuming the option KSH_ARRAYS is unset) corresponds to the error number.
Error numbers num before the last known error which have no name are given the name
Enum in the array.

Note that aliases for errors are not handled; only the canonical name is used.

sysparams
A readonly associative array. The keys are:

pid Returns the process ID of the current process, even in subshells. Compare
$$, which returns the process ID of the main shell process.

ppid Returns the process ID of the parent of the current process, even in sub-
shells. Compare $PPID, which returns the process ID of the parent of the
main shell process.

procsubstpid
Returns the process ID of the last process started for process substitution,
i.e. the <(...) and >(...) expansions.

THE ZSH/NET/TCP MODULE
The zsh/net/tcp module makes available one builtin command:

ztcp [ -acflLtv ] [ -d fd ] [ args ]
ztcp is implemented as a builtin to allow full use of shell command line editing,
file I/O, and job control mechanisms.

If ztcp is run with no options, it will output the contents of its session table.

If it is run with only the option -L, it will output the contents of the session
table in a format suitable for automatic parsing. The option is ignored if given
with a command to open or close a session. The output consists of a set of lines,
one per session, each containing the following elements separated by spaces:

File descriptor
The file descriptor in use for the connection. For normal inbound (I) and
outbound (O) connections this may be read and written by the usual shell
mechanisms. However, it should only be close with `ztcp -c'.

Connection type
A letter indicating how the session was created:

Z A session created with the zftp command.

L A connection opened for listening with `ztcp -l'.

I An inbound connection accepted with `ztcp -a'.

O An outbound connection created with `ztcp host ...'.

The local host
This is usually set to an all-zero IP address as the address of the local-
host is irrelevant.

The local port
This is likely to be zero unless the connection is for listening.

The remote host
This is the fully qualified domain name of the peer, if available, else an
IP address. It is an all-zero IP address for a session opened for listen-
ing.

The remote port
This is zero for a connection opened for listening.

Outbound Connections
ztcp [ -v ] [ -d fd ] host [ port ]
Open a new TCP connection to host. If the port is omitted, it will default to port
23. The connection will be added to the session table and the shell parameter RE-
PLY will be set to the file descriptor associated with that connection.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

Inbound Connections
ztcp -l [ -v ] [ -d fd ] port
ztcp -l will open a socket listening on TCP port. The socket will be added to the
session table and the shell parameter REPLY will be set to the file descriptor as-
sociated with that listener.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

ztcp -a [ -tv ] [ -d targetfd ] listenfd
ztcp -a will accept an incoming connection to the port associated with listenfd.
The connection will be added to the session table and the shell parameter REPLY
will be set to the file descriptor associated with the inbound connection.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

If -t is specified, ztcp will return if no incoming connection is pending. Other-
wise it will wait for one.

In order to elicit more verbose output, use -v.

Closing Connections
ztcp -cf [ -v ] [ fd ]
ztcp -c [ -v ] [ fd ]
ztcp -c will close the socket associated with fd. The socket will be removed from
the session table. If fd is not specified, ztcp will close everything in the ses-
sion table.

Normally, sockets registered by zftp (see zshmodules(1) ) cannot be closed this
way. In order to force such a socket closed, use -f.

In order to elicit more verbose output, use -v.

Example
Here is how to create a TCP connection between two instances of zsh. We need to pick an
unassigned port; here we use the randomly chosen 5123.

On host1,
zmodload zsh/net/tcp
ztcp -l 5123
listenfd=$REPLY
ztcp -a $listenfd
fd=$REPLY
The second from last command blocks until there is an incoming connection.

Now create a connection from host2 (which may, of course, be the same machine):
zmodload zsh/net/tcp
ztcp host1 5123
fd=$REPLY

Now on each host, $fd contains a file descriptor for talking to the other. For example,
on host1:
print This is a message >&$fd
and on host2:
read -r line <&$fd; print -r - $line
prints `This is a message'.

To tidy up, on host1:
ztcp -c $listenfd
ztcp -c $fd
and on host2
ztcp -c $fd

THE ZSH/TERMCAP MODULE
The zsh/termcap module makes available one builtin command:

echotc cap [ arg ... ]
Output the termcap value corresponding to the capability cap, with optional argu-
ments.

The zsh/termcap module makes available one parameter:

termcap
An associative array that maps termcap capability codes to their values.

THE ZSH/TERMINFO MODULE
The zsh/terminfo module makes available one builtin command:

echoti cap [ arg ]
Output the terminfo value corresponding to the capability cap, instantiated with
arg if applicable.

The zsh/terminfo module makes available one parameter:

terminfo
An associative array that maps terminfo capability names to their values.

THE ZSH/ZFTP MODULE
The zsh/zftp module makes available one builtin command:

zftp subcommand [ args ]
The zsh/zftp module is a client for FTP (file transfer protocol). It is imple-
mented as a builtin to allow full use of shell command line editing, file I/O, and
job control mechanisms. Often, users will access it via shell functions providing
a more powerful interface; a set is provided with the zsh distribution and is de-
scribed in zshzftpsys(1). However, the zftp command is entirely usable in its own
right.

All commands consist of the command name zftp followed by the name of a subcommand.
These are listed below. The return status of each subcommand is supposed to re-
flect the success or failure of the remote operation. See a description of the
variable ZFTP_VERBOSE for more information on how responses from the server may be
printed.

Subcommands
open host[:port] [ user [ password [ account ] ] ]
Open a new FTP session to host, which may be the name of a TCP/IP connected host or
an IP number in the standard dot notation. If the argument is in the form
host:port, open a connection to TCP port port instead of the standard FTP port 21.
This may be the name of a TCP service or a number: see the description of
ZFTP_PORT below for more information.

If IPv6 addresses in colon format are used, the host should be surrounded by quoted
square brackets to distinguish it from the port, for example
'[fe80::203:baff:fe02:8b56]'. For consistency this is allowed with all forms of
host.

Remaining arguments are passed to the login subcommand. Note that if no arguments
beyond host are supplied, open will not automatically call login. If no arguments
at all are supplied, open will use the parameters set by the params subcommand.

After a successful open, the shell variables ZFTP_HOST, ZFTP_PORT, ZFTP_IP and
ZFTP_SYSTEM are available; see `Variables' below.

login [ name [ password [ account ] ] ]
user [ name [ password [ account ] ] ]
Login the user name with parameters password and account. Any of the parameters
can be omitted, and will be read from standard input if needed (name is always
needed). If standard input is a terminal, a prompt for each one will be printed on
standard error and password will not be echoed. If any of the parameters are not
used, a warning message is printed.

After a successful login, the shell variables ZFTP_USER, ZFTP_ACCOUNT and ZFTP_PWD
are available; see `Variables' below.

This command may be re-issued when a user is already logged in, and the server will
first be reinitialized for a new user.

params [ host [ user [ password [ account ] ] ] ]
params -
Store the given parameters for a later open command with no arguments. Only those
given on the command line will be remembered. If no arguments are given, the pa-
rameters currently set are printed, although the password will appear as a line of
stars; the return status is one if no parameters were set, zero otherwise.

Any of the parameters may be specified as a `?', which may need to be quoted to
protect it from shell expansion. In this case, the appropriate parameter will be
read from stdin as with the login subcommand, including special handling of pass-
word. If the `?' is followed by a string, that is used as the prompt for reading
the parameter instead of the default message (any necessary punctuation and white-
space should be included at the end of the prompt). The first letter of the param-
eter (only) may be quoted with a `\'; hence an argument "\\$word" guarantees that
the string from the shell parameter $word will be treated literally, whether or not
it begins with a `?'.

If instead a single `-' is given, the existing parameters, if any, are deleted. In
that case, calling open with no arguments will cause an error.

The list of parameters is not deleted after a close, however it will be deleted if
the zsh/zftp module is unloaded.

For example,

zftp params ftp.elsewhere.xx juser '?Password for juser: '

will store the host ftp.elsewhere.xx and the user juser and then prompt the user
for the corresponding password with the given prompt.

test Test the connection; if the server has reported that it has closed the connection
(maybe due to a timeout), return status 2; if no connection was open anyway, return
status 1; else return status 0. The test subcommand is silent, apart from messages
printed by the $ZFTP_VERBOSE mechanism, or error messages if the connection closes.
There is no network overhead for this test.

The test is only supported on systems with either the select(2) or poll(2) system
calls; otherwise the message `not supported on this system' is printed instead.

The test subcommand will automatically be called at the start of any other subcom-
mand for the current session when a connection is open.

cd directory
Change the remote directory to directory. Also alters the shell variable ZFTP_PWD.

cdup Change the remote directory to the one higher in the directory tree. Note that cd
.. will also work correctly on non-UNIX systems.

dir [ arg ... ]
Give a (verbose) listing of the remote directory. The args are passed directly to
the server. The command's behaviour is implementation dependent, but a UNIX server
will typically interpret args as arguments to the ls command and with no arguments
return the result of `ls -l'. The directory is listed to standard output.

ls [ arg ... ]
Give a (short) listing of the remote directory. With no arg, produces a raw list
of the files in the directory, one per line. Otherwise, up to vagaries of the
server implementation, behaves similar to dir.

type [ type ]
Change the type for the transfer to type, or print the current type if type is ab-
sent. The allowed values are `A' (ASCII), `I' (Image, i.e. binary), or `B' (a syn-
onym for `I').

The FTP default for a transfer is ASCII. However, if zftp finds that the remote
host is a UNIX machine with 8-bit byes, it will automatically switch to using bi-
nary for file transfers upon open. This can subsequently be overridden.

The transfer type is only passed to the remote host when a data connection is es-
tablished; this command involves no network overhead.

ascii The same as type A.

binary The same as type I.

mode [ S | B ]
Set the mode type to stream (S) or block (B). Stream mode is the default; block
mode is not widely supported.

remote file ...
local [ file ... ]
Print the size and last modification time of the remote or local files. If there
is more than one item on the list, the name of the file is printed first. The
first number is the file size, the second is the last modification time of the file
in the format CCYYMMDDhhmmSS consisting of year, month, date, hour, minutes and
seconds in GMT. Note that this format, including the length, is guaranteed, so
that time strings can be directly compared via the [[ builtin's < and > operators,
even if they are too long to be represented as integers.

Not all servers support the commands for retrieving this information. In that
case, the remote command will print nothing and return status 2, compared with sta-
tus 1 for a file not found.

The local command (but not remote) may be used with no arguments, in which case the
information comes from examining file descriptor zero. This is the same file as
seen by a put command with no further redirection.

get file ...
Retrieve all files from the server, concatenating them and sending them to standard
output.

put file ...
For each file, read a file from standard input and send that to the remote host
with the given name.

append file ...
As put, but if the remote file already exists, data is appended to it instead of
overwriting it.

getat file point
putat file point
appendat file point
Versions of get, put and append which will start the transfer at the given point in
the remote file. This is useful for appending to an incomplete local file. How-
ever, note that this ability is not universally supported by servers (and is not
quite the behaviour specified by the standard).

delete file ...
Delete the list of files on the server.

mkdir directory
Create a new directory directory on the server.

rmdir directory
Delete the directory directory on the server.

rename old-name new-name
Rename file old-name to new-name on the server.

site arg ...
Send a host-specific command to the server. You will probably only need this if
instructed by the server to use it.

quote arg ...
Send the raw FTP command sequence to the server. You should be familiar with the
FTP command set as defined in RFC959 before doing this. Useful commands may in-
clude STAT and HELP. Note also the mechanism for returning messages as described
for the variable ZFTP_VERBOSE below, in particular that all messages from the con-
trol connection are sent to standard error.

close
quit Close the current data connection. This unsets the shell parameters ZFTP_HOST,
ZFTP_PORT, ZFTP_IP, ZFTP_SYSTEM, ZFTP_USER, ZFTP_ACCOUNT, ZFTP_PWD, ZFTP_TYPE and
ZFTP_MODE.

session [ sessname ]
Allows multiple FTP sessions to be used at once. The name of the session is an ar-
bitrary string of characters; the default session is called `default'. If this
command is called without an argument, it will list all the current sessions; with
an argument, it will either switch to the existing session called sessname, or cre-
ate a new session of that name.

Each session remembers the status of the connection, the set of connection-specific
shell parameters (the same set as are unset when a connection closes, as given in
the description of close), and any user parameters specified with the params sub-
command. Changing to a previous session restores those values; changing to a new
session initialises them in the same way as if zftp had just been loaded. The name
of the current session is given by the parameter ZFTP_SESSION.

rmsession [ sessname ]
Delete a session; if a name is not given, the current session is deleted. If the
current session is deleted, the earliest existing session becomes the new current
session, otherwise the current session is not changed. If the session being
deleted is the only one, a new session called `default' is created and becomes the
current session; note that this is a new session even if the session being deleted
is also called `default'. It is recommended that sessions not be deleted while
background commands which use zftp are still active.

Parameters
The following shell parameters are used by zftp. Currently none of them are special.

ZFTP_TMOUT
Integer. The time in seconds to wait for a network operation to complete before
returning an error. If this is not set when the module is loaded, it will be given
the default value 60. A value of zero turns off timeouts. If a timeout occurs on
the control connection it will be closed. Use a larger value if this occurs too
frequently.

ZFTP_IP
Readonly. The IP address of the current connection in dot notation.

ZFTP_HOST
Readonly. The hostname of the current remote server. If the host was opened as an
IP number, ZFTP_HOST contains that instead; this saves the overhead for a name
lookup, as IP numbers are most commonly used when a nameserver is unavailable.

ZFTP_PORT
Readonly. The number of the remote TCP port to which the connection is open (even
if the port was originally specified as a named service). Usually this is the
standard FTP port, 21.

In the unlikely event that your system does not have the appropriate conversion
functions, this appears in network byte order. If your system is little-endian,
the port then consists of two swapped bytes and the standard port will be reported
as 5376. In that case, numeric ports passed to zftp open will also need to be in
this format.

ZFTP_SYSTEM
Readonly. The system type string returned by the server in response to an FTP SYST
request. The most interesting case is a string beginning "UNIX Type: L8", which
ensures maximum compatibility with a local UNIX host.

ZFTP_TYPE
Readonly. The type to be used for data transfers , either `A' or `I'. Use the
type subcommand to change this.

ZFTP_USER
Readonly. The username currently logged in, if any.

ZFTP_ACCOUNT
Readonly. The account name of the current user, if any. Most servers do not re-
quire an account name.

ZFTP_PWD
Readonly. The current directory on the server.

ZFTP_CODE
Readonly. The three digit code of the last FTP reply from the server as a string.
This can still be read after the connection is closed, and is not changed when the
current session changes.

ZFTP_REPLY
Readonly. The last line of the last reply sent by the server. This can still be
read after the connection is closed, and is not changed when the current session
changes.

ZFTP_SESSION
Readonly. The name of the current FTP session; see the description of the session
subcommand.

ZFTP_PREFS
A string of preferences for altering aspects of zftp's behaviour. Each preference
is a single character. The following are defined:

P Passive: attempt to make the remote server initiate data transfers. This
is slightly more efficient than sendport mode. If the letter S occurs later
in the string, zftp will use sendport mode if passive mode is not available.

S Sendport: initiate transfers by the FTP PORT command. If this occurs be-
fore any P in the string, passive mode will never be attempted.

D Dumb: use only the bare minimum of FTP commands. This prevents the vari-
ables ZFTP_SYSTEM and ZFTP_PWD from being set, and will mean all connections
default to ASCII type. It may prevent ZFTP_SIZE from being set during a
transfer if the server does not send it anyway (many servers do).

If ZFTP_PREFS is not set when zftp is loaded, it will be set to a default of `PS',
i.e. use passive mode if available, otherwise fall back to sendport mode.

ZFTP_VERBOSE
A string of digits between 0 and 5 inclusive, specifying which responses from the
server should be printed. All responses go to standard error. If any of the num-
bers 1 to 5 appear in the string, raw responses from the server with reply codes
beginning with that digit will be printed to standard error. The first digit of
the three digit reply code is defined by RFC959 to correspond to:

1. A positive preliminary reply.

2. A positive completion reply.

3. A positive intermediate reply.

4. A transient negative completion reply.

5. A permanent negative completion reply.

It should be noted that, for unknown reasons, the reply `Service not available',
which forces termination of a connection, is classified as 421, i.e. `transient
negative', an interesting interpretation of the word `transient'.

The code 0 is special: it indicates that all but the last line of multiline
replies read from the server will be printed to standard error in a processed for-
mat. By convention, servers use this mechanism for sending information for the
user to read. The appropriate reply code, if it matches the same response, takes
priority.

If ZFTP_VERBOSE is not set when zftp is loaded, it will be set to the default value
450, i.e., messages destined for the user and all errors will be printed. A null
string is valid and specifies that no messages should be printed.

Functions
zftp_chpwd
If this function is set by the user, it is called every time the directory changes
on the server, including when a user is logged in, or when a connection is closed.
In the last case, $ZFTP_PWD will be unset; otherwise it will reflect the new direc-
tory.

zftp_progress
If this function is set by the user, it will be called during a get, put or append
operation each time sufficient data has been received from the host. During a get,
the data is sent to standard output, so it is vital that this function should write
to standard error or directly to the terminal, not to standard output.

When it is called with a transfer in progress, the following additional shell pa-
rameters are set:

ZFTP_FILE
The name of the remote file being transferred from or to.

ZFTP_TRANSFER
A G for a get operation and a P for a put operation.

ZFTP_SIZE
The total size of the complete file being transferred: the same as the first
value provided by the remote and local subcommands for a particular file.
If the server cannot supply this value for a remote file being retrieved, it
will not be set. If input is from a pipe the value may be incorrect and
correspond simply to a full pipe buffer.

ZFTP_COUNT
The amount of data so far transferred; a number between zero and $ZFTP_SIZE,
if that is set. This number is always available.

The function is initially called with ZFTP_TRANSFER set appropriately and
ZFTP_COUNT set to zero. After the transfer is finished, the function will be
called one more time with ZFTP_TRANSFER set to GF or PF, in case it wishes to tidy
up. It is otherwise never called twice with the same value of ZFTP_COUNT.

Sometimes the progress meter may cause disruption. It is up to the user to decide
whether the function should be defined and to use unfunction when necessary.

Problems
A connection may not be opened in the left hand side of a pipe as this occurs in a sub-
shell and the file information is not updated in the main shell. In the case of type or
mode changes or closing the connection in a subshell, the information is returned but
variables are not updated until the next call to zftp. Other status changes in subshells
will not be reflected by changes to the variables (but should be otherwise harmless).

Deleting sessions while a zftp command is active in the background can have unexpected ef-
fects, even if it does not use the session being deleted. This is because all shell sub-
processes share information on the state of all connections, and deleting a session
changes the ordering of that information.

On some operating systems, the control connection is not valid after a fork(), so that op-
erations in subshells, on the left hand side of a pipeline, or in the background are not
possible, as they should be. This is presumably a bug in the operating system.

THE ZSH/ZLE MODULE
The zsh/zle module contains the Zsh Line Editor. See zshzle(1).

THE ZSH/ZLEPARAMETER MODULE
The zsh/zleparameter module defines two special parameters that can be used to access in-
ternal information of the Zsh Line Editor (see zshzle(1)).

keymaps
This array contains the names of the keymaps currently defined.

widgets
This associative array contains one entry per widget. The name of the widget is the
key and the value gives information about the widget. It is either
the string `builtin' for builtin widgets,
a string of the form `user:name' for user-defined widgets,
where name is the name of the shell function implementing the widget,
a string of the form `completion:type:name'
for completion widgets,
or a null value if the widget is not yet fully defined. In the penultimate case,
type is the name of the builtin widget the completion widget imitates in its behav-
ior and name is the name of the shell function implementing the completion widget.

THE ZSH/ZPROF MODULE
When loaded, the zsh/zprof causes shell functions to be profiled. The profiling results
can be obtained with the zprof builtin command made available by this module. There is no
way to turn profiling off other than unloading the module.

zprof [ -c ]
Without the -c option, zprof lists profiling results to standard output. The for-
mat is comparable to that of commands like gprof.

At the top there is a summary listing all functions that were called at least once.
This summary is sorted in decreasing order of the amount of time spent in each.
The lines contain the number of the function in order, which is used in other parts
of the list in suffixes of the form `[num]', then the number of calls made to the
function. The next three columns list the time in milliseconds spent in the func-
tion and its descendants, the average time in milliseconds spent in the function
and its descendants per call and the percentage of time spent in all shell func-
tions used in this function and its descendants. The following three columns give
the same information, but counting only the time spent in the function itself. The
final column shows the name of the function.

After the summary, detailed information about every function that was invoked is
listed, sorted in decreasing order of the amount of time spent in each function and
its descendants. Each of these entries consists of descriptions for the functions
that called the function described, the function itself, and the functions that
were called from it. The description for the function itself has the same format
as in the summary (and shows the same information). The other lines don't show the
number of the function at the beginning and have their function named indented to
make it easier to distinguish the line showing the function described in the sec-
tion from the surrounding lines.

The information shown in this case is almost the same as in the summary, but only
refers to the call hierarchy being displayed. For example, for a calling function
the column showing the total running time lists the time spent in the described
function and its descendants only for the times when it was called from that par-
ticular calling function. Likewise, for a called function, this columns lists the
total time spent in the called function and its descendants only for the times when
it was called from the function described.

Also in this case, the column showing the number of calls to a function also shows
a slash and then the total number of invocations made to the called function.

As long as the zsh/zprof module is loaded, profiling will be done and multiple in-
vocations of the zprof builtin command will show the times and numbers of calls
since the module was loaded. With the -c option, the zprof builtin command will
reset its internal counters and will not show the listing.

THE ZSH/ZPTY MODULE
The zsh/zpty module offers one builtin:

zpty [ -e ] [ -b ] name [ arg ... ]
The arguments following name are concatenated with spaces between, then executed as
a command, as if passed to the eval builtin. The command runs under a newly as-
signed pseudo-terminal; this is useful for running commands non-interactively which
expect an interactive environment. The name is not part of the command, but is
used to refer to this command in later calls to zpty.

With the -e option, the pseudo-terminal is set up so that input characters are
echoed.

With the -b option, input to and output from the pseudo-terminal are made
non-blocking.

The shell parameter REPLY is set to the file descriptor assigned to the master side
of the pseudo-terminal. This allows the terminal to be monitored with ZLE descrip-
tor handlers (see zshzle(1)) or manipulated with sysread and syswrite (see THE
ZSH/SYSTEM MODULE in zshmodules(1)). Warning: Use of sysread and syswrite is not
recommended; use zpty -r and zpty -w unless you know exactly what you are doing.

zpty -d [ name ... ]
The second form, with the -d option, is used to delete commands previously started,
by supplying a list of their names. If no name is given, all commands are deleted.
Deleting a command causes the HUP signal to be sent to the corresponding process.

zpty -w [ -n ] name [ string ... ]
The -w option can be used to send the to command name the given strings as input
(separated by spaces). If the -n option is not given, a newline is added at the
end.

If no string is provided, the standard input is copied to the pseudo-terminal; this
may stop before copying the full input if the pseudo-terminal is non-blocking. The
exact input is always copied: the -n option is not applied.

Note that the command under the pseudo-terminal sees this input as if it were
typed, so beware when sending special tty driver characters such as word-erase,
line-kill, and end-of-file.

zpty -r [ -mt ] name [ param [ pattern ] ]
The -r option can be used to read the output of the command name. With only a name
argument, the output read is copied to the standard output. Unless the pseudo-ter-
minal is non-blocking, copying continues until the command under the pseudo-termi-
nal exits; when non-blocking, only as much output as is immediately available is
copied. The return status is zero if any output is copied.

When also given a param argument, at most one line is read and stored in the param-
eter named param. Less than a full line may be read if the pseudo-terminal is
non-blocking. The return status is zero if at least one character is stored in
param.

If a pattern is given as well, output is read until the whole string read matches
the pattern, even in the non-blocking case. The return status is zero if the
string read matches the pattern, or if the command has exited but at least one
character could still be read. If the option -m is present, the return status is
zero only if the pattern matches. As of this writing, a maximum of one megabyte of
output can be consumed this way; if a full megabyte is read without matching the
pattern, the return status is non-zero.

In all cases, the return status is non-zero if nothing could be read, and is 2 if
this is because the command has finished.

If the -r option is combined with the -t option, zpty tests whether output is
available before trying to read. If no output is available, zpty immediately re-
turns the status 1. When used with a pattern, the behaviour on a failed poll is
similar to when the command has exited: the return value is zero if at least one
character could still be read even if the pattern failed to match.

zpty -t name
The -t option without the -r option can be used to test whether the command name is
still running. It returns a zero status if the command is running and a non-zero
value otherwise.

zpty [ -L ]
The last form, without any arguments, is used to list the commands currently de-
fined. If the -L option is given, this is done in the form of calls to the zpty
builtin.

THE ZSH/ZSELECT MODULE
The zsh/zselect module makes available one builtin command:

zselect [ -rwe ] [ -t timeout ] [ -a array ] [ -A assoc ] [ fd ... ]
The zselect builtin is a front-end to the `select' system call, which blocks until
a file descriptor is ready for reading or writing, or has an error condition, with
an optional timeout. If this is not available on your system, the command prints
an error message and returns status 2 (normal errors return status 1). For more
information, see your systems documentation for select(3). Note there is no con-
nection with the shell builtin of the same name.

Arguments and options may be intermingled in any order. Non-option arguments are
file descriptors, which must be decimal integers. By default, file descriptors are
to be tested for reading, i.e. zselect will return when data is available to be
read from the file descriptor, or more precisely, when a read operation from the
file descriptor will not block. After a -r, -w and -e, the given file descriptors
are to be tested for reading, writing, or error conditions. These options and an
arbitrary list of file descriptors may be given in any order.

(The presence of an `error condition' is not well defined in the documentation for
many implementations of the select system call. According to recent versions of
the POSIX specification, it is really an exception condition, of which the only
standard example is out-of-band data received on a socket. So zsh users are un-
likely to find the -e option useful.)

The option `-t timeout' specifies a timeout in hundredths of a second. This may be
zero, in which case the file descriptors will simply be polled and zselect will re-
turn immediately. It is possible to call zselect with no file descriptors and a
non-zero timeout for use as a finer-grained replacement for `sleep'; note, however,
the return status is always 1 for a timeout.

The option `-a array' indicates that array should be set to indicate the file de-
scriptor(s) which are ready. If the option is not given, the array reply will be
used for this purpose. The array will contain a string similar to the arguments
for zselect. For example,

zselect -t 0 -r 0 -w 1

might return immediately with status 0 and $reply containing `-r 0 -w 1' to show
that both file descriptors are ready for the requested operations.

The option `-A assoc' indicates that the associative array assoc should be set to
indicate the file descriptor(s) which are ready. This option overrides the option
-a, nor will reply be modified. The keys of assoc are the file descriptors, and
the corresponding values are any of the characters `rwe' to indicate the condition.

The command returns status 0 if some file descriptors are ready for reading. If
the operation timed out, or a timeout of 0 was given and no file descriptors were
ready, or there was an error, it returns status 1 and the array will not be set
(nor modified in any way). If there was an error in the select operation the ap-
propriate error message is printed.

THE ZSH/ZUTIL MODULE
The zsh/zutil module only adds some builtins:

zstyle [ -L [ metapattern [ style ] ] ]
zstyle [ -e | - | -- ] pattern style string ...
zstyle -d [ pattern [ style ... ] ]
zstyle -g name [ pattern [ style ] ]
zstyle -{a|b|s} context style name [ sep ]
zstyle -{T|t} context style [ string ... ]
zstyle -m context style pattern
This builtin command is used to define and lookup styles. Styles are pairs of
names and values, where the values consist of any number of strings. They are
stored together with patterns and lookup is done by giving a string, called the
`context', which is matched against the patterns. The definition stored for the
most specific pattern that matches will be returned.

A pattern is considered to be more specific than another if it contains more compo-
nents (substrings separated by colons) or if the patterns for the components are
more specific, where simple strings are considered to be more specific than pat-
terns and complex patterns are considered to be more specific than the pattern `*'.
A `*' in the pattern will match zero or more characters in the context; colons are
not treated specially in this regard. If two patterns are equally specific, the
tie is broken in favour of the pattern that was defined first.

Example

For example, to define your preferred form of precipitation depending on which city
you're in, you might set the following in your zshrc:

zstyle ':weather:europe:*' preferred-precipitation rain
zstyle ':weather:europe:germany:* preferred-precipitation none
zstyle ':weather:europe:germany:*:munich' preferred-precipitation snow

Then, the fictional `weather' plugin might run under the hood a command such as

zstyle -s ":weather:${continent}:${country}:${county}:${city}" preferred-precipitation REPLY

in order to retrieve your preference into the scalar variable $REPLY.

Usage

The forms that operate on patterns are the following.

zstyle [ -L [ metapattern [ style ] ] ]
Without arguments, lists style definitions. Styles are shown in alphabetic
order and patterns are shown in the order zstyle will test them.

If the -L option is given, listing is done in the form of calls to zstyle.
The optional first argument, metapattern, is a pattern which will be matched
against the string supplied as pattern when the style was defined. Note:
this means, for example, `zstyle -L ":completion:*"' will match any supplied
pattern beginning `:completion:', not just ":completion:*": use ':comple-
tion:\*' to match that. The optional second argument limits the output to a
specific style (not a pattern). -L is not compatible with any other op-
tions.

zstyle [ - | -- | -e ] pattern style string ...
Defines the given style for the pattern with the strings as the value. If
the -e option is given, the strings will be concatenated (separated by spa-
ces) and the resulting string will be evaluated (in the same way as it is
done by the eval builtin command) when the style is looked up. In this case
the parameter `reply' must be assigned to set the strings returned after the
evaluation. Before evaluating the value, reply is unset, and if it is still
unset after the evaluation, the style is treated as if it were not set.

zstyle -d [ pattern [ style ... ] ]
Delete style definitions. Without arguments all definitions are deleted,
with a pattern all definitions for that pattern are deleted and if any
styles are given, then only those styles are deleted for the pattern.

zstyle -g name [ pattern [ style ] ]
Retrieve a style definition. The name is used as the name of an array in
which the results are stored. Without any further arguments, all patterns
defined are returned. With a pattern the styles defined for that pattern are
returned and with both a pattern and a style, the value strings of that com-
bination is returned.

The other forms can be used to look up or test styles for a given context.

zstyle -s context style name [ sep ]
The parameter name is set to the value of the style interpreted as a string.
If the value contains several strings they are concatenated with spaces (or
with the sep string if that is given) between them.

Return 0 if the style is set, 1 otherwise.

zstyle -b context style name
The value is stored in name as a boolean, i.e. as the string `yes' if the
value has only one string and that string is equal to one of `yes', `true',
`on', or `1'. If the value is any other string or has more than one string,
the parameter is set to `no'.

Return 0 if name is set to `yes', 1 otherwise.

zstyle -a context style name
The value is stored in name as an array. If name is declared as an associa-
tive array, the first, third, etc. strings are used as the keys and the
other strings are used as the values.

Return 0 if the style is set, 1 otherwise.

zstyle -t context style [ string ... ]
zstyle -T context style [ string ... ]
Test the value of a style, i.e. the -t option only returns a status (sets
$?). Without any string the return status is zero if the style is defined
for at least one matching pattern, has only one string in its value, and
that is equal to one of `true', `yes', `on' or `1'. If any strings are given
the status is zero if and only if at least one of the strings is equal to at
least one of the strings in the value. If the style is defined but doesn't
match, the return status is 1. If the style is not defined, the status is 2.

The -T option tests the values of the style like -t, but it returns status
zero (rather than 2) if the style is not defined for any matching pattern.

zstyle -m context style pattern
Match a value. Returns status zero if the pattern matches at least one of
the strings in the value.

zformat -f param format spec ...
zformat -a array sep spec ...
This builtin provides two different forms of formatting. The first form is selected
with the -f option. In this case the format string will be modified by replacing
sequences starting with a percent sign in it with strings from the specs. Each
spec should be of the form `char:string' which will cause every appearance of the
sequence `%char' in format to be replaced by the string. The `%' sequence may also
contain optional minimum and maximum field width specifications between the `%' and
the `char' in the form `%min.maxc', i.e. the minimum field width is given first and
if the maximum field width is used, it has to be preceded by a dot. Specifying a
minimum field width makes the result be padded with spaces to the right if the
string is shorter than the requested width. Padding to the left can be achieved by
giving a negative minimum field width. If a maximum field width is specified, the
string will be truncated after that many characters. After all `%' sequences for
the given specs have been processed, the resulting string is stored in the parame-
ter param.

The %-escapes also understand ternary expressions in the form used by prompts. The
% is followed by a `(' and then an ordinary format specifier character as described
above. There may be a set of digits either before or after the `('; these specify
a test number, which defaults to zero. Negative numbers are also allowed. An ar-
bitrary delimiter character follows the format specifier, which is followed by a
piece of `true' text, the delimiter character again, a piece of `false' text, and a
closing parenthesis. The complete expression (without the digits) thus looks like
`%(X.text1.text2)', except that the `.' character is arbitrary. The value given
for the format specifier in the char:string expressions is evaluated as a mathemat-
ical expression, and compared with the test number. If they are the same, text1 is
output, else text2 is output. A parenthesis may be escaped in text2 as %). Either
of text1 or text2 may contain nested %-escapes.

For example:

zformat -f REPLY "The answer is '%3(c.yes.no)'." c:3

outputs "The answer is 'yes'." to REPLY since the value for the format specifier c
is 3, agreeing with the digit argument to the ternary expression.

The second form, using the -a option, can be used for aligning strings. Here, the
specs are of the form `left:right' where `left' and `right' are arbitrary strings.
These strings are modified by replacing the colons by the sep string and padding
the left strings with spaces to the right so that the sep strings in the result
(and hence the right strings after them) are all aligned if the strings are printed
below each other. All strings without a colon are left unchanged and all strings
with an empty right string have the trailing colon removed. In both cases the
lengths of the strings are not used to determine how the other strings are to be
aligned. A colon in the left string can be escaped with a backslash. The result-
ing strings are stored in the array.

zregexparse
This implements some internals of the _regex_arguments function.

zparseopts [ -D -E -F -K -M ] [ -a array ] [ -A assoc ] [ - ] spec ...
This builtin simplifies the parsing of options in positional parameters, i.e. the
set of arguments given by $*. Each spec describes one option and must be of the
form `opt[=array]'. If an option described by opt is found in the positional pa-
rameters it is copied into the array specified with the -a option; if the optional
`=array' is given, it is instead copied into that array, which should be declared
as a normal array and never as an associative array.

Note that it is an error to give any spec without an `=array' unless one of the -a
or -A options is used.

Unless the -E option is given, parsing stops at the first string that isn't de-
scribed by one of the specs. Even with -E, parsing always stops at a positional
parameter equal to `-' or `--'. See also -F.

The opt description must be one of the following. Any of the special characters
can appear in the option name provided it is preceded by a backslash.

name
name+ The name is the name of the option without the leading `-'. To specify a
GNU-style long option, one of the usual two leading `-' must be included in
name; for example, a `--file' option is represented by a name of `-file'.

If a `+' appears after name, the option is appended to array each time it is
found in the positional parameters; without the `+' only the last occurrence
of the option is preserved.

If one of these forms is used, the option takes no argument, so parsing
stops if the next positional parameter does not also begin with `-' (unless
the -E option is used).

name:
name:-
name:: If one or two colons are given, the option takes an argument; with one
colon, the argument is mandatory and with two colons it is optional. The
argument is appended to the array after the option itself.

An optional argument is put into the same array element as the option name
(note that this makes empty strings as arguments indistinguishable). A
mandatory argument is added as a separate element unless the `:-' form is
used, in which case the argument is put into the same element.

A `+' as described above may appear between the name and the first colon.

In all cases, option-arguments must appear either immediately following the option
in the same positional parameter or in the next one. Even an optional argument may
appear in the next parameter, unless it begins with a `-'. There is no special
handling of `=' as with GNU-style argument parsers; given the spec `-foo:', the po-
sitional parameter `--foo=bar' is parsed as `--foo' with an argument of `=bar'.

When the names of two options that take no arguments overlap, the longest one wins,
so that parsing for the specs `-foo -foobar' (for example) is unambiguous. However,
due to the aforementioned handling of option-arguments, ambiguities may arise when
at least one overlapping spec takes an argument, as in `-foo: -foobar'. In that
case, the last matching spec wins.

The options of zparseopts itself cannot be stacked because, for example, the stack
`-DEK' is indistinguishable from a spec for the GNU-style long option `--DEK'. The
options of zparseopts itself are:

-a array
As described above, this names the default array in which to store the
recognised options.

-A assoc
If this is given, the options and their values are also put into an associa-
tive array with the option names as keys and the arguments (if any) as the
values.

-D If this option is given, all options found are removed from the positional
parameters of the calling shell or shell function, up to but not including
any not described by the specs. If the first such parameter is `-' or `--',
it is removed as well. This is similar to using the shift builtin.

-E This changes the parsing rules to not stop at the first string that isn't
described by one of the specs. It can be used to test for or (if used to-
gether with -D) extract options and their arguments, ignoring all other op-
tions and arguments that may be in the positional parameters. As indicated
above, parsing still stops at the first `-' or `--' not described by a spec,
but it is not removed when used with -D.

-F If this option is given, zparseopts immediately stops at the first op-
tion-like parameter not described by one of the specs, prints an error mes-
sage, and returns status 1. Removal (-D) and extraction (-E) are not per-
formed, and option arrays are not updated. This provides basic validation
for the given options.

Note that the appearance in the positional parameters of an option without
its required argument always aborts parsing and returns an error as de-
scribed above regardless of whether this option is used.

-K With this option, the arrays specified with the -a option and with the `=ar-
ray' forms are kept unchanged when none of the specs for them is used. Oth-
erwise the entire array is replaced when any of the specs is used. Individ-
ual elements of associative arrays specified with the -A option are pre-
served by -K. This allows assignment of default values to arrays before
calling zparseopts.

-M This changes the assignment rules to implement a map among equivalent option
names. If any spec uses the `=array' form, the string array is interpreted
as the name of another spec, which is used to choose where to store the val-
ues. If no other spec is found, the values are stored as usual. This
changes only the way the values are stored, not the way $* is parsed, so re-
sults may be unpredictable if the `name+' specifier is used inconsistently.

For example,

set -- -a -bx -c y -cz baz -cend
zparseopts a=foo b:=bar c+:=bar

will have the effect of

foo=(-a)
bar=(-b x -c y -c z)

The arguments from `baz' on will not be used.

As an example for the -E option, consider:

set -- -a x -b y -c z arg1 arg2
zparseopts -E -D b:=bar

will have the effect of

bar=(-b y)
set -- -a x -c z arg1 arg2

I.e., the option -b and its arguments are taken from the positional parameters and
put into the array bar.

The -M option can be used like this:

set -- -a -bx -c y -cz baz -cend
zparseopts -A bar -M a=foo b+: c:=b

to have the effect of

foo=(-a)
bar=(-a '' -b xyz)

zsh 5.8.1 February 12, 2022 ZSHMODULES(1)

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