ZSHMODULES(1) User Commands 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 system.

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/watch
Reporting of login and logout events.

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 being 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 optional 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 attributes 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 capability 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, deprecated 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 module 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 currently 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 suffixes, 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 EXTENDED_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 precedence
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 following 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 terminals 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 zshcontrib(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 zshoptions(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 terminal 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 LISTPROMPT, 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 parameter 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 explicitly 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, respectively.

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 normal
editing mode but without leaving menu selection; after each
character completion is tried again and the list changes to
contain only the new matches; the completion 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 selection 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 selected. 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 completion 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 interesting
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 parsing. 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,
display 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 arguments. 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 specification currently used. The -i option
does the directory tests for the ignore-parents 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 using the -Q option to compadd and perform
quoting themselves. Instead of interpreting 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 parameters, 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 assigned. Note in particular the curses convention
that vertical values appear before horizontal values.

If addwin is given an existing window as the final argument,
the new window is created 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 exists 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 redrawn. 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 before 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 available
(in particular if the library is ncurses), specifying the
foreground or background 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 allowed 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 multibyte
character (use of ASCII characters only is recommended). As
the specified set of attributes override the existing
background, turning attributes off in the arguments 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 window
up or down the given number of lines without changing the
current cursor position (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 input 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 implies 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 returns status 0 if mouse
handling is possible, else status 1. Otherwise, the possible
arguments (which may be combined on the same command line) are
as follows. delay 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 releases, 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 intval 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 notation, 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 extension (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 refresh 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 defined 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 module 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 created 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 | -n ] format [ epochtime [ nanoseconds ] ]
strftime -r [ -q ] [ -s scalar | -n ] 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 seconds since the epoch,
and nanoseconds may additionally be used to specify the number
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.

-n Suppress printing a newline after the formatted string.

-q Run quietly; suppress printing of all error messages
described below. Errors 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 ignored 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 message.

If either of the system functions strptime or mktime is
not available, status 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 produce 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 notional accuracy is to nanoseconds if
the clock_gettime call is available and to microseconds
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 element and the remainder of the time since
the epoch in nanoseconds in the second element. 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 following 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 database 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 associative array arrayname linked to
the file. To create a local tied array, the parameter must
first be declared, so commands similar to the following would
be executed 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 parameter. 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 example, 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. Using 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 argument 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 behaviour, 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 directory
itself.

The -s option is a zsh extension to chown functionality. It
enables paranoid behaviour, 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 directory 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 destination 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
directory 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 succeed 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. Typically 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 exists. 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 behaviour, 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 remove /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
directory 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, ABDAY_{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[myfile]'' works as
expected, editing the file `myfile'.

When the array is accessed as a whole, the keys are the names
of files in the current 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=("${(f@)mapfile[filename]}")'.
The double quotes and the `@' are necessary to prevent empty
lines from being removed. Note that if the file ends with a
newline, the shell will split on the final newline, generating
an additional empty field; this can be suppressed by using
`array=("${(f@)${mapfile[filename]%$'\n'}}")'.

Limitations

Although reading and writing of the file in question is efficiently
handled, zsh's internal 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 handling 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 example,

(( 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 function
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 immediately after a call to
gamma or lgamma. Note also that `signgam()' and `signgam' are
distinct expressions.

The functions min, max, and sum are defined not in this module but in
the zmathfunc autoloadable 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 convert 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 random 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 initialised
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 parameters
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 terminal 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 commonly 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 available 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 immediately after commands in the
global zshenv file (typically /etc/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 processing
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
parent of the functions directory containing version-specific
functions. (These directories can be configured when zsh is built
using the --enable-site-scriptdir=dir and --enable-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/zshenv. The module exists
simply to allow the shell to make arrangements for new users without
the need for intervention by package maintainers and system
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 option, 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 external 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. Setting 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 autoload 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 enabled. 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 defined. 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 directory.

history
This associative array maps history event numbers to the full
history lines. Although it is presented as an associative
array, the array of all values (${history[@]}) 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.

See the jobs builtin for how job information is provided in a
subshell.

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.

See the jobs builtin for how job information is provided in a
subshell.

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 currently in,
one of `running', `suspended', or `done'. The mark is `+' for
the current 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.

See the jobs builtin for how job information is provided in a
subshell.

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 functrace, 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 function, if any.

funcsourcetrace
This array contains the file names and line numbers of the
points where the functions, sourced files, and (if EVAL_LINENO
is set) eval commands currently being executed 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 reported 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 instead.

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 opposite 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 interactively 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-insensitive pattern. Option -m will
compile a multi-line pattern; that is, ^ and $ will match
newlines within the pattern. Option -x will compile an
extended pattern, 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" indicates 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 position 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 [ {+|-}AHUahlmrtux ] [ {+|-}EFLRZi [ n ] ] [ name[=value] ...
] The private builtin accepts all the same options and arguments
as local (zshbuiltins(1)) except for the `-T' option. Tied
parameters may not be made private.

The `-p' option is presently a no-op because the state of
private parameters cannot reliably be reloaded. This also
applies to printing private parameters with `typeset -p'.

If used at the top level (outside a function scope), private
creates a normal parameter 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, private 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
parameter. This may change in the future.

As with other typeset equivalents, private is both a builtin and a
reserved word, so arrays 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 declare 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 before 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 without 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. However, the private name may not be created outside
the local scope when it was not previously declared.

+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.

Note that the zsh/regex module logic relies on the host
system. The same expr and regex pair could produce different
results on different platforms if a regex with non-standard
syntax is given.

For example, no syntax for matching a word boundary is defined
in the POSIX extended regular expression standard. GNU libc
and BSD libc both provide such syntaxes as extensions (\b and
[[:<:]]/[[:>:]] respectively), but neither of these syntaxes
is supported by both of these implementations.

Refer to the regcomp(3) and re_format(7) manual pages on your
system for locally-supported syntax.

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 specified in either absolute or relative time,
and either as hours, minutes and (optionally) seconds
separated by a colon, or seconds alone. An absolute number of
seconds indicates the time since the epoch (1970/01/01 00:00);
this is useful in combination 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 afterwards. 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' command 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 arguments (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 `-' otherwise), 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 editing, 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 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.

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 listenfd. 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. Otherwise 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:zstat'.

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, respectively, 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 array, 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 element;
if -n is given, the file name appears as a separate
array element preceding all the others. Other
formatting options are respected.

-H hash
Similar to -A, but instead assign the values to hash.
The keys are the elements 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).
In particular, -F %s.%N can be used to show timestamps
with nanosecond precision if supported by the system.
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 appropriate) 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 element 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
formatted 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 numbers. 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 status 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
descriptor 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, depending on the system, some
may not be available.
cloexec
mark file to be closed when other programs are executed
(else the file descriptor 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

nonblock
the file is opened in nonblocking mode

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, otherwise 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 because 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 interrupts 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, written.

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 adjusted 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; otherwise 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 result 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 ] [ -i interval ] [ -f var ] [-er] file
zsystem flock -u fd_expr
The builtin zsystem's subcommand flock performs advisory file
locking (via the fcntl(2) system call) over the entire
contents of the given file. This form of locking 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
often convenient to create file locks within subshells, since
the lock is automatically 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 descriptor 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; fractional seconds are allowed. During this
period, the shell will attempt to lock the file every interval
seconds if the -i interval option is given, otherwise once a
second. (This interval is shortened before the last attempt
if needed, so that the shell waits only until the timeout and
not longer.) If the attempt times out, status 2 is returned.

(Note: timeout is limited to 2^30-1 seconds (about 34 years),
and interval to 0.999 * LONG_MAX microseconds (only about 35
minutes on 32-bit systems).)

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 reading and writing. The file descriptor
is opened accordingly.

zsystem supports subcommand
The builtin zsystem's subcommand supports tests whether a
given subcommand is supported. 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 current process ID of the parent of the
current process, even in subshells. Compare $PPID,
which returns the process ID of the initial 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 localhost 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 listening.

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 REPLY 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 associated 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. Otherwise 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 session 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 arguments.

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/WATCH MODULE
The zsh/watch module can be used to report when specific users log in
or out. This is controlled via the following parameters.

LOGCHECK
The interval in seconds between checks for login/logout
activity using the watch parameter.

watch <S> <Z> (WATCH <S>)
An array (colon-separated list) of login/logout events to
report.

If it contains the single word `all', then all login/logout
events are reported. If it contains the single word `notme',
then all events are reported as with `all' except $USERNAME.

An entry in this list may consist of a username, an `@'
followed by a remote hostname, and a `%' followed by a line
(tty). Any of these may be a pattern (be sure to quote this
during the assignment to watch so that it does not immediately
perform file generation); the setting of the EXTENDED_GLOB
option is respected. Any or all of these components may be
present in an entry; if a login/logout event matches all of
them, it is reported.

For example, with the EXTENDED_GLOB option set, the following:

watch=('^(pws|barts)')

causes reports for activity associated with any user other
than pws or barts.

WATCHFMT
The format of login/logout reports if the watch parameter is
set. Default is `%n has %a %l from %m'. Recognizes the
following escape sequences:

%n The name of the user that logged in/out.

%a The observed action, i.e. "logged on" or "logged off".

%l The line (tty) the user is logged in on.

%M The full hostname of the remote host.

%m The hostname up to the first `.'. If only the IP
address is available or the utmp field contains the
name of an X-windows display, the whole name is
printed.

NOTE: The `%m' and `%M' escapes will work only if there
is a host name field in the utmp on your machine.
Otherwise they are treated as ordinary strings.

%F{color} (%f)
Start (stop) using a different foreground color.

%K{color} (%k)
Start (stop) using a different background color.

%S (%s)
Start (stop) standout mode.

%U (%u)
Start (stop) underline mode.

%B (%b)
Start (stop) boldface mode.

%t
%@ The time, in 12-hour, am/pm format.

%T The time, in 24-hour format.

%w The date in `day-dd' format.

%W The date in `mm/dd/yy' format.

%D The date in `yy-mm-dd' format.

%D{string}
The date formatted as string using the strftime
function, with zsh extensions as described by EXPANSION
OF PROMPT SEQUENCES in zshmisc(1).

%(x:true-text:false-text)
Specifies a ternary expression. The character
following the x is arbitrary; the same character is
used to separate the text for the "true" result from
that for the "false" result. Both the separator and
the right parenthesis may be escaped with a backslash.
Ternary expressions may be nested.

The test character x may be any one of `l', `n', `m' or
`M', which indicate a `true' result if the
corresponding escape sequence would return a non-empty
value; or it may be `a', which indicates a `true'
result if the watched user has logged in, or `false' if
he has logged out. Other characters evaluate to
neither true nor false; the entire expression is
omitted in this case.

If the result is `true', then the true-text is
formatted according to the rules above and printed, and
the false-text is skipped. If `false', the true-text
is skipped and the false-text is formatted and printed.
Either or both of the branches may be empty, but both
separators must be present in any case.

Furthermore, the zsh/watch module makes available one builtin
command:

log List all users currently logged in who are affected by the
current setting of the watch parameter.

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 implemented 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 described 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 reflect 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 parameters
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
password. 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 whitespace should be
included at the end of the prompt). The first letter of the
parameter (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 subcommand 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 absent. The allowed values are `A' (ASCII),
`I' (Image, i.e. binary), or `B' (a synonym 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 binary 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 established; 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 status 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. However, 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 include 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 control 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 arbitrary 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 create 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
subcommand. 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 require 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 before any P in the string, passive mode
will never be attempted.

D Dumb: use only the bare minimum of FTP commands. This
prevents the variables 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 numbers 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 format. 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
directory.

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 parameters 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 subshell 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 effects, even if it does not use the session
being deleted. This is because all shell subprocesses 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 operations 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 internal 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 behavior 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 format 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 function 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 functions 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
section 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 particular 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 invocations 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 assigned
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 descriptor
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-terminal is
non-blocking, copying continues until the command under the
pseudo-terminal 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 parameter 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 returns 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 defined. 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 system's documentation for select(3). Note there is no
connection 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 unlikely 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 return 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 descriptor(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 appropriate 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 components (substrings separated by colons) or
if the patterns for the components are more specific, where
simple strings are considered to be more specific than
patterns 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, a fictional `weather' plugin might state in its
documentation that it looks up the preferred-precipitation
style under the
`:weather:continent:day-of-the-week:phase-of-the-moon'
context. According to this, you might set the following in
your zshrc:

zstyle ':weather:europe:*' preferred-precipitation rain
zstyle ':weather:*:Sunday:*' preferred-precipitation snow

Then the plugin would run under the hood a command such as

zstyle -s ":weather:${continent}:${day_of_week}:${moon_phase}" preferred-precipitation REPLY

in order to retrieve your preference into the scalar variable
$REPLY. On Sundays $REPLY would be set to `snow'; in Europe
it would be set to `rain'; and on Sundays in Europe it would
be set to `snow' again, because the patterns
`:weather:europe:*' and `:weather:*:Sunday:*' both match the
context argument to zstyle -s, are equally specific, and the
latter is more specific (because it has more colon-separated
components).

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 ':completion:\*' to match that. The optional
second argument limits the output to a specific style
(not a pattern). -L is not compatible with any other
options.

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 spaces) 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 combination 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 associative 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 -F param format spec ...
zformat -a array sep spec ...
This builtin provides 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 parameter 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 arbitrary 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 mathematical 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.

With -F instead of -f, ternary expressions choose between the
`true' or `false' text on the basis of whether the format
specifier is present and non-empty. A test number indicates a
minimum width for the value given in the format specifier.
Negative numbers reverse this, so the test is for whether the
value exceeds a maximum width.

The 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
resulting 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
parameters 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 described 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 positional 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 associative 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 together with -D)
extract options and their arguments, ignoring all other
options 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 option-like parameter not described by one
of the specs, prints an error message, and returns
status 1. Removal (-D) and extraction (-E) are not
performed, 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 described above
regardless of whether this option is used.

-K With this option, the arrays specified with the -a
option and with the `=array' forms are kept unchanged
when none of the specs for them is used. Otherwise the
entire array is replaced when any of the specs is used.
Individual elements of associative arrays specified
with the -A option are preserved 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 values. 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
results 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 5.9 May 14, 2022 ZSHMODULES(1)