This is zsh.info, produced by makeinfo version 7.3 from zsh.texi.

INFO-DIR-SECTION Utilities
START-INFO-DIR-ENTRY
* ZSH: (zsh).                     The Z Shell Manual.
END-INFO-DIR-ENTRY


File: zsh.info,  Node: Completion System Variables,  Next: Completion Directories,  Prev: Completion Functions,  Up: Completion System

20.7 Completion System Variables
================================

There are some standard variables, initialised by the _main_complete
function and then used from other functions.

The standard variables are:

_comp_caller_options
     The completion system uses setopt to set a number of options.  This
     allows functions to be written without concern for compatibility
     with every possible combination of user options.  However,
     sometimes completion needs to know what the user's option
     preferences are.  These are saved in the _comp_caller_options
     associative array.  Option names, spelled in lowercase without
     underscores, are mapped to one or other of the strings 'on' and
     'off'.

_comp_priv_prefix
     Completion functions such as _sudo can set the _comp_priv_prefix
     array to a command prefix that may then be used by _call_program to
     match the privileges when calling programs to generate matches.

Two more features are offered by the _main_complete function.  The
arrays compprefuncs and comppostfuncs may contain names of functions
that are to be called immediately before or after completion has been
tried.  A function will only be called once unless it explicitly
reinserts itself into the array.


File: zsh.info,  Node: Completion Directories,  Prev: Completion System Variables,  Up: Completion System

20.8 Completion Directories
===========================

In the source distribution, the files are contained in various
subdirectories of the Completion directory.  They may have been
installed in the same structure, or into one single function directory.
The following is a description of the files found in the original
directory structure.  If you wish to alter an installed file, you will
need to copy it to some directory which appears earlier in your fpath
than the standard directory where it appears.

Base
     The core functions and special completion widgets automatically
     bound to keys.  You will certainly need most of these, though will
     probably not need to alter them.  Many of these are documented
     above.

Zsh
     Functions for completing arguments of shell builtin commands and
     utility functions for this.  Some of these are also used by
     functions from the Unix directory.

Unix
     Functions for completing arguments of external commands and suites
     of commands.  They may need modifying for your system, although in
     many cases some attempt is made to decide which version of a
     command is present.  For example, completion for the mount command
     tries to determine the system it is running on, while completion
     for many other utilities try to decide whether the GNU version of
     the command is in use, and hence whether the --help option is
     supported.

X, AIX, BSD, ...
     Completion and utility function for commands available only on some
     systems.  These are not arranged hierarchically, so, for example,
     both the Linux and Debian directories, as well as the X directory,
     may be useful on your system.


File: zsh.info,  Node: Completion Using compctl,  Next: Zsh Modules,  Prev: Completion System,  Up: Top

21 Completion Using compctl
***************************

21.1 Types of completion
========================

This version of zsh has two ways of performing completion of words on
the command line.  New users of the shell may prefer to use the newer
and more powerful system based on shell functions; this is described in
*note Completion System::, and the basic shell mechanisms which support
it are described in *note Completion Widgets::.  This chapter describes
the older compctl command.

21.2 Description
================

compctl [ -CDT ] OPTIONS [ COMMAND ... ]
compctl [ -CDT ] OPTIONS [ -x PATTERN OPTIONS - ... -- ]
        [ + OPTIONS [ -x ... -- ] ... [+] ] [ COMMAND ... ]
compctl -M MATCH-SPECS ...
compctl -L [ -CDTM ] [ COMMAND ... ]
compctl + COMMAND ...

Control the editor's completion behavior according to the supplied set
of OPTIONS.  Various editing commands, notably expand-or-complete-word,
usually bound to tab, will attempt to complete a word typed by the user,
while others, notably delete-char-or-list, usually bound to ^D in EMACS
editing mode, list the possibilities; compctl controls what those
possibilities are.  They may for example be filenames (the most common
case, and hence the default), shell variables, or words from a
user-specified list.
* Menu:

* Command Flags::
* Option Flags::
* Alternative Completion::
* Extended Completion::
* Example::


File: zsh.info,  Node: Command Flags,  Next: Option Flags,  Up: Completion Using compctl

21.3 Command Flags
==================

Completion of the arguments of a command may be different for each
command or may use the default.  The behavior when completing the
command word itself may also be separately specified.  These correspond
to the following flags and arguments, all of which (except for -L) may
be combined with any combination of the OPTIONS described subsequently
in *note Option Flags:::

COMMAND ...
     controls completion for the named commands, which must be listed
     last on the command line.  If completion is attempted for a command
     with a pathname containing slashes and no completion definition is
     found, the search is retried with the last pathname component.  If
     the command starts with a =, completion is tried with the pathname
     of the command.

     Any of the COMMAND strings may be patterns of the form normally
     used for filename generation.  These should be quoted to protect
     them from immediate expansion; for example the command string
     'foo*' arranges for completion of the words of any command
     beginning with foo.  When completion is attempted, all pattern
     completions are tried in the reverse order of their definition
     until one matches.  By default, completion then proceeds as normal,
     i.e.  the shell will try to generate more matches for the specific
     command on the command line; this can be overridden by including
     -tn in the flags for the pattern completion.

     Note that aliases are expanded before the command name is
     determined unless the COMPLETE_ALIASES option is set.  Commands may
     not be combined with the -C, -D or -T flags.

-C
     controls completion when the command word itself is being
     completed.  If no compctl -C command has been issued, the names of
     any executable command (whether in the path or specific to the
     shell, such as aliases or functions) are completed.

-D
     controls default completion behavior for the arguments of commands
     not assigned any special behavior.  If no compctl -D command has
     been issued, filenames are completed.

-T
     supplies completion flags to be used before any other processing is
     done, even before processing for compctls defined for specific
     commands.  This is especially useful when combined with extended
     completion (the -x flag, see *note Extended Completion:: below).
     Using this flag you can define default behavior which will apply to
     all commands without exception, or you can alter the standard
     behavior for all commands.  For example, if your access to the user
     database is too slow and/or it contains too many users (so that
     completion after '~' is too slow to be usable), you can use

          compctl -T -x 's[~] C[0,[^/]#]' -k friends -S/ -tn

     to complete the strings in the array friends after a '~'.  The
     C[...] argument is necessary so that this form of ~-completion is
     not tried after the directory name is finished.

-L
     lists the existing completion behavior in a manner suitable for
     putting into a start-up script; the existing behavior is not
     changed.  Any combination of the above forms, or the -M flag (which
     must follow the -L flag), may be specified, otherwise all defined
     completions are listed.  Any other flags supplied are ignored.

_no argument_
     If no argument is given, compctl lists all defined completions in
     an abbreviated form; with a list of OPTIONS, all completions with
     those flags set (not counting extended completion) are listed.

If the + flag is alone and followed immediately by the COMMAND list, the
completion behavior for all the commands in the list is reset to the
default.  In other words, completion will subsequently use the options
specified by the -D flag.

The form with -M as the first and only option defines global matching
specifications (see *note Completion Matching Control::).  The match
specifications given will be used for every completion attempt (only
when using compctl, not with the new completion system) and are tried in
the order in which they are defined until one generates at least one
match.  E.g.:

     compctl -M '' 'm:{a-zA-Z}={A-Za-z}'

This will first try completion without any global match specifications
(the empty string) and, if that generates no matches, will try case
insensitive completion.


File: zsh.info,  Node: Option Flags,  Next: Alternative Completion,  Prev: Command Flags,  Up: Completion Using compctl

21.4 Option Flags
=================

[ -fcFBdeaRGovNAIOPZEnbjrzu/12 ]
[ -k ARRAY ] [ -g GLOBSTRING ] [ -s SUBSTSTRING ]
[ -K FUNCTION ]
[ -Q ] [ -P PREFIX ] [ -S SUFFIX ]
[ -W FILE-PREFIX ] [ -H NUM PATTERN ]
[ -q ] [ -X EXPLANATION ] [ -Y EXPLANATION ]
[ -y FUNC-OR-VAR ] [ -l CMD ] [ -h CMD ] [ -U ]
[ -t CONTINUE ] [ -J NAME ] [ -V NAME ]
[ -M MATCH-SPEC ]

The remaining OPTIONS specify the type of command arguments to look for
during completion.  Any combination of these flags may be specified; the
result is a sorted list of all the possibilities.  The options are as
follows.
* Menu:

* Simple Flags::
* Flags with Arguments::
* Control Flags::


File: zsh.info,  Node: Simple Flags,  Next: Flags with Arguments,  Up: Option Flags

21.4.1 Simple Flags
-------------------

These produce completion lists made up by the shell itself:

-f
     Filenames and file system paths.

-/
     Just file system paths.

-c
     Command names, including aliases, shell functions, builtins and
     reserved words.

-F
     Function names.

-B
     Names of builtin commands.

-m
     Names of external commands.

-w
     Reserved words.

-a
     Alias names.

-R
     Names of regular (non-global) aliases.

-G
     Names of global aliases.

-d
     This can be combined with -F, -B, -w, -a, -R and -G to get names of
     disabled functions, builtins, reserved words or aliases.

-e
     This option (to show enabled commands) is in effect by default, but
     may be combined with -d; -de in combination with -F, -B, -w, -a, -R
     and -G will complete names of functions, builtins, reserved words
     or aliases whether or not they are disabled.

-o
     Names of shell options (see *note Options::).

-v
     Names of any variable defined in the shell.

-N
     Names of scalar (non-array) parameters.

-A
     Array names.

-I
     Names of integer variables.

-O
     Names of read-only variables.

-p
     Names of parameters used by the shell (including special
     parameters).

-Z
     Names of shell special parameters.

-E
     Names of environment variables.

-n
     Named directories.

-b
     Key binding names.

-j
     Job names: the first word of the job leader's command line.  This
     is useful with the kill builtin.

-r
     Names of running jobs.

-z
     Names of suspended jobs.

-u
     User names.


File: zsh.info,  Node: Flags with Arguments,  Next: Control Flags,  Prev: Simple Flags,  Up: Option Flags

21.4.2 Flags with Arguments
---------------------------

These have user supplied arguments to determine how the list of
completions is to be made up:

-k ARRAY
     Names taken from the elements of $ARRAY (note that the '$' does not
     appear on the command line).  Alternatively, the argument ARRAY
     itself may be a set of space- or comma-separated values in
     parentheses, in which any delimiter may be escaped with a
     backslash; in this case the argument should be quoted.  For
     example,

          compctl -k "(cputime filesize datasize stacksize
          	       coredumpsize resident descriptors)" limit

-g GLOBSTRING
     The GLOBSTRING is expanded using filename globbing; it should be
     quoted to protect it from immediate expansion.  The resulting
     filenames are taken as the possible completions.  Use '*(/)'
     instead of '*/' for directories.  The fignore special parameter is
     not applied to the resulting files.  More than one pattern may be
     given separated by blanks.  (Note that brace expansion is _not_
     part of globbing.  Use the syntax '(either|or)' to match
     alternatives.)

-s SUBSTSTRING
     The SUBSTSTRING is split into words and these words are than
     expanded using all shell expansion mechanisms (see *note
     Expansion::).  The resulting words are taken as possible
     completions.  The fignore special parameter is not applied to the
     resulting files.  Note that -g is faster for filenames.

-K FUNCTION
     Call the given function to get the completions.  Unless the name
     starts with an underscore, the function is passed two arguments:
     the prefix and the suffix of the word on which completion is to be
     attempted, in other words those characters before the cursor
     position, and those from the cursor position onwards.  The whole
     command line can be accessed with the -c and -l flags of the read
     builtin.  The function should set the variable reply to an array
     containing the completions (one completion per element); note that
     reply should not be made local to the function.  From such a
     function the command line can be accessed with the -c and -l flags
     to the read builtin.  For example,

          function whoson { reply=(`users`); }
          compctl -K whoson talk

     completes only logged-on users after 'talk'.  Note that 'whoson'
     must return an array, so 'reply=`users`' would be incorrect.

-H NUM PATTERN
     The possible completions are taken from the last NUM history lines.
     Only words matching PATTERN are taken.  If NUM is zero or negative
     the whole history is searched and if PATTERN is the empty string
     all words are taken (as with '*').  A typical use is

          compctl -D -f + -H 0 ''

     which forces completion to look back in the history list for a word
     if no filename matches.


File: zsh.info,  Node: Control Flags,  Prev: Flags with Arguments,  Up: Option Flags

21.4.3 Control Flags
--------------------

These do not directly specify types of name to be completed, but
manipulate the options that do:

-Q
     This instructs the shell not to quote any metacharacters in the
     possible completions.  Normally the results of a completion are
     inserted into the command line with any metacharacters quoted so
     that they are interpreted as normal characters.  This is
     appropriate for filenames and ordinary strings.  However, for
     special effects, such as inserting a backquoted expression from a
     completion array (-k) so that the expression will not be evaluated
     until the complete line is executed, this option must be used.

-P PREFIX
     The PREFIX is inserted just before the completed string; any
     initial part already typed will be completed and the whole PREFIX
     ignored for completion purposes.  For example,

          compctl -j -P "%" kill

     inserts a '%' after the kill command and then completes job names.

-S SUFFIX
     When a completion is found the SUFFIX is inserted after the
     completed string.  In the case of menu completion the suffix is
     inserted immediately, but it is still possible to cycle through the
     list of completions by repeatedly hitting the same key.

-W FILE-PREFIX
     With directory FILE-PREFIX: for command, file, directory and
     globbing completion (options -c, -f, -/, -g), the file prefix is
     implicitly added in front of the completion.  For example,

          compctl -/ -W ~/Mail maildirs

     completes any subdirectories to any depth beneath the directory
     ~/Mail, although that prefix does not appear on the command line.
     The FILE-PREFIX may also be of the form accepted by the -k flag,
     i.e.  the name of an array or a literal list in parenthesis.  In
     this case all the directories in the list will be searched for
     possible completions.

-q
     If used with a suffix as specified by the -S option, this causes
     the suffix to be removed if the next character typed is a blank or
     does not insert anything or if the suffix consists of only one
     character and the next character typed is the same character; this
     the same rule used for the AUTO_REMOVE_SLASH option.  The option is
     most useful for list separators (comma, colon, etc.).

-l CMD
     This option restricts the range of command line words that are
     considered to be arguments.  If combined with one of the extended
     completion patterns 'p[...]', 'r[...]', or 'R[...]'  (see *note
     Extended Completion:: below) the range is restricted to the range
     of arguments specified in the brackets.  Completion is then
     performed as if these had been given as arguments to the CMD
     supplied with the option.  If the CMD string is empty the first
     word in the range is instead taken as the command name, and command
     name completion performed on the first word in the range.  For
     example,

          compctl -x 'r[-exec,;]' -l '' -- find

     completes arguments between '-exec' and the following ';' (or the
     end of the command line if there is no such string) as if they were
     a separate command line.

-h CMD
     Normally zsh completes quoted strings as a whole.  With this
     option, completion can be done separately on different parts of
     such strings.  It works like the -l option but makes the completion
     code work on the parts of the current word that are separated by
     spaces.  These parts are completed as if they were arguments to the
     given CMD.  If CMD is the empty string, the first part is completed
     as a command name, as with -l.

-U
     Use the whole list of possible completions, whether or not they
     actually match the word on the command line.  The word typed so far
     will be deleted.  This is most useful with a function (given by the
     -K option) which can examine the word components passed to it (or
     via the read builtin's -c and -l flags) and use its own criteria to
     decide what matches.  If there is no completion, the original word
     is retained.  Since the produced possible completions seldom have
     interesting common prefixes and suffixes, menu completion is
     started immediately if AUTO_MENU is set and this flag is used.

-y FUNC-OR-VAR
     The list provided by FUNC-OR-VAR is displayed instead of the list
     of completions whenever a listing is required; the actual
     completions to be inserted are not affected.  It can be provided in
     two ways.  Firstly, if FUNC-OR-VAR begins with a $ it defines a
     variable, or if it begins with a left parenthesis a literal array,
     which contains the list.  A variable may have been set by a call to
     a function using the -K option.  Otherwise it contains the name of
     a function which will be executed to create the list.  The function
     will be passed as an argument list all matching completions,
     including prefixes and suffixes expanded in full, and should set
     the array reply to the result.  In both cases, the display list
     will only be retrieved after a complete list of matches has been
     created.

     Note that the returned list does not have to correspond, even in
     length, to the original set of matches, and may be passed as a
     scalar instead of an array.  No special formatting of characters is
     performed on the output in this case; in particular, newlines are
     printed literally and if they appear output in columns is
     suppressed.

-X EXPLANATION
     Print EXPLANATION when trying completion on the current set of
     options.  A '%n' in this string is replaced by the number of
     matches that were added for this explanation string.  The
     explanation only appears if completion was tried and there was no
     unique match, or when listing completions.  Explanation strings
     will be listed together with the matches of the group specified
     together with the -X option (using the -J or -V option).  If the
     same explanation string is given to multiple -X options, the string
     appears only once (for each group) and the number of matches shown
     for the '%n' is the total number of all matches for each of these
     uses.  In any case, the explanation string will only be shown if
     there was at least one match added for the explanation string.

     The sequences %B, %b, %S, %s, %U, and %u specify output attributes
     (bold, standout, and underline), %F, %f, %K, %k specify foreground
     and background colours, and %{...%} can be used to include literal
     escape sequences as in prompts.

-Y EXPLANATION
     Identical to -X, except that the EXPLANATION first undergoes
     expansion following the usual rules for strings in double quotes.
     The expansion will be carried out after any functions are called
     for the -K or -y options, allowing them to set variables.

-t CONTINUE
     The CONTINUE-string contains a character that specifies which set
     of completion flags should be used next.  It is useful:

     (i) With -T, or when trying a list of pattern completions, when
     compctl would usually continue with ordinary processing after
     finding matches; this can be suppressed with '-tn'.

     (ii) With a list of alternatives separated by +, when compctl would
     normally stop when one of the alternatives generates matches.  It
     can be forced to consider the next set of completions by adding
     '-t+' to the flags of the alternative before the '+'.

     (iii) In an extended completion list (see below), when compctl
     would normally continue until a set of conditions succeeded, then
     use only the immediately following flags.  With '-t-', compctl will
     continue trying extended completions after the next '-'; with '-tx'
     it will attempt completion with the default flags, in other words
     those before the '-x'.

-J NAME
     This gives the name of the group the matches should be placed in.
     Groups are listed and sorted separately; likewise, menu completion
     will offer the matches in the groups in the order in which the
     groups were defined.  If no group name is explicitly given, the
     matches are stored in a group named default.  The first time a
     group name is encountered, a group with that name is created.
     After that all matches with the same group name are stored in that
     group.

     This can be useful with non-exclusive alternative completions.  For
     example, in

          compctl -f -J files -t+ + -v -J variables foo

     both files and variables are possible completions, as the -t+
     forces both sets of alternatives before and after the + to be
     considered at once.  Because of the -J options, however, all files
     are listed before all variables.

-V NAME
     Like -J, but matches within the group will not be sorted in
     listings nor in menu completion.  These unsorted groups are in a
     different name space from the sorted ones, so groups defined as -J
     files and -V files are distinct.

-1
     If given together with the -V option, makes only consecutive
     duplicates in the group be removed.  Note that groups with and
     without this flag are in different name spaces.

-2
     If given together with the -J or -V option, makes all duplicates be
     kept.  Again, groups with and without this flag are in different
     name spaces.

-M MATCH-SPEC
     This defines additional matching control specifications that should
     be used only when testing words for the list of flags this flag
     appears in.  The format of the MATCH-SPEC string is described in
     *note Completion Matching Control::.


File: zsh.info,  Node: Alternative Completion,  Next: Extended Completion,  Prev: Option Flags,  Up: Completion Using compctl

21.5 Alternative Completion
===========================

compctl [ -CDT ] OPTIONS + OPTIONS [ + ... ] [ + ] COMMAND ...

The form with '+' specifies alternative options.  Completion is tried
with the options before the first '+'.  If this produces no matches
completion is tried with the flags after the '+' and so on.  If there
are no flags after the last '+' and a match has not been found up to
that point, default completion is tried.  If the list of flags contains
a -t with a + character, the next list of flags is used even if the
current list produced matches.


File: zsh.info,  Node: Extended Completion,  Next: Example,  Prev: Alternative Completion,  Up: Completion Using compctl

Additional options are available that restrict completion to some part
of the command line; this is referred to as 'extended completion'.

21.6 Extended Completion
========================

compctl [ -CDT ] OPTIONS -x PATTERN OPTIONS - ... --
        [ COMMAND ... ]
compctl [ -CDT ] OPTIONS [ -x PATTERN OPTIONS - ... -- ]
        [ + OPTIONS [ -x ... -- ] ... [+] ] [ COMMAND ... ]

The form with '-x' specifies extended completion for the commands given;
as shown, it may be combined with alternative completion using '+'.
Each PATTERN is examined in turn; when a match is found, the
corresponding OPTIONS, as described in *note Option Flags:: above, are
used to generate possible completions.  If no PATTERN matches, the
OPTIONS given before the -x are used.

Note that each pattern should be supplied as a single argument and
should be quoted to prevent expansion of metacharacters by the shell.

A PATTERN is built of sub-patterns separated by commas; it matches if at
least one of these sub-patterns matches (they are 'or'ed).  These
sub-patterns are in turn composed of other sub-patterns separated by
white spaces which match if all of the sub-patterns match (they are
'and'ed).  An element of the sub-patterns is of the form 'C[...][...]',
where the pairs of brackets may be repeated as often as necessary, and
matches if any of the sets of brackets match (an 'or').  The example
below makes this clearer.

The elements may be any of the following:

s[STRING]...
     Matches if the current word on the command line starts with one of
     the strings given in brackets.  The STRING is not removed and is
     not part of the completion.

S[STRING]...
     Like s[STRING] except that the STRING is part of the completion.

p[FROM,TO]...
     Matches if the number of the current word is between one of the
     FROM and TO pairs inclusive.  The comma and TO are optional; TO
     defaults to the same value as FROM.  The numbers may be negative:
     -N refers to the N'th last word on the line.

c[OFFSET,STRING]...
     Matches if the STRING matches the word offset by OFFSET from the
     current word position.  Usually OFFSET will be negative.

C[OFFSET,PATTERN]...
     Like c but using pattern matching instead.

w[INDEX,STRING]...
     Matches if the word in position INDEX is equal to the corresponding
     STRING.  Note that the word count is made after any alias
     expansion.

W[INDEX,PATTERN]...
     Like w but using pattern matching instead.

n[INDEX,STRING]...
     Matches if the current word contains STRING.  Anything up to and
     including the INDEXth occurrence of this string will not be
     considered part of the completion, but the rest will.  INDEX may be
     negative to count from the end: in most cases, INDEX will be 1 or
     -1.  For example,

          compctl -s '`users`' -x 'n[1,@]' -k hosts -- talk

     will usually complete usernames, but if you insert an @ after the
     name, names from the array HOSTS (assumed to contain hostnames,
     though you must make the array yourself) will be completed.  Other
     commands such as rcp can be handled similarly.

N[INDEX,STRING]...
     Like n except that the string will be taken as a character class.
     Anything up to and including the INDEXth occurrence of any of the
     characters in STRING will not be considered part of the completion.

m[MIN,MAX]...
     Matches if the total number of words lies between MIN and MAX
     inclusive.

r[STR1,STR2]...
     Matches if the cursor is after a word with prefix STR1.  If there
     is also a word with prefix STR2 on the command line after the one
     matched by STR1 it matches only if the cursor is before this word.
     If the comma and STR2 are omitted, it matches if the cursor is
     after a word with prefix STR1.

R[STR1,STR2]...
     Like r but using pattern matching instead.

q[STR]...
     Matches the word currently being completed is in single quotes and
     the STR begins with the letter 's', or if completion is done in
     double quotes and STR starts with the letter 'd', or if completion
     is done in backticks and STR starts with a 'b'.


File: zsh.info,  Node: Example,  Prev: Extended Completion,  Up: Completion Using compctl

21.7 Example
============

     compctl -u -x 's[+] c[-1,-f],s[-f+]' \
       -g '~/Mail/*(:t)' - 's[-f],c[-1,-f]' -f -- mail

This is to be interpreted as follows:

If the current command is mail, then

     if ((the current word begins with + and the previous word is -f) or
     (the current word begins with -f+)), then complete the
     non-directory part (the ':t' glob modifier) of files in the
     directory ~/Mail; else

     if the current word begins with -f or the previous word was -f,
     then complete any file; else

     complete user names.


File: zsh.info,  Node: Zsh Modules,  Next: Calendar Function System,  Prev: Completion Using compctl,  Up: Top

22 Zsh Modules
**************

22.1 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 *note Shell Builtin Commands::.

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.

* Menu:

* The zsh/attr Module::
* The zsh/cap Module::
* The zsh/clone Module::
* The zsh/compctl Module::
* The zsh/complete Module::
* The zsh/complist Module::
* The zsh/computil Module::
* The zsh/curses Module::
* The zsh/datetime Module::
* The zsh/db/gdbm Module::
* The zsh/deltochar Module::
* The zsh/example Module::
* The zsh/files Module::
* The zsh/langinfo Module::
* The zsh/mapfile Module::
* The zsh/mathfunc Module::
* The zsh/nearcolor Module::
* The zsh/newuser Module::
* The zsh/parameter Module::
* The zsh/pcre Module::
* The zsh/param/private Module::
* The zsh/regex Module::
* The zsh/sched Module::
* The zsh/net/socket Module::
* The zsh/stat Module::
* The zsh/system Module::
* The zsh/net/tcp Module::
* The zsh/termcap Module::
* The zsh/terminfo Module::
* The zsh/watch Module::
* The zsh/zftp Module::
* The zsh/zle Module::
* The zsh/zleparameter Module::
* The zsh/zprof Module::
* The zsh/zpty Module::
* The zsh/zselect Module::
* The zsh/zutil Module::


File: zsh.info,  Node: The zsh/attr Module,  Next: The zsh/cap Module,  Up: Zsh Modules

22.2 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.


File: zsh.info,  Node: The zsh/cap Module,  Next: The zsh/clone Module,  Prev: The zsh/attr Module,  Up: Zsh Modules

22.3 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.


File: zsh.info,  Node: The zsh/clone Module,  Next: The zsh/compctl Module,  Prev: The zsh/cap Module,  Up: Zsh Modules

22.4 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:

        • 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)
        • 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.


File: zsh.info,  Node: The zsh/compctl Module,  Next: The zsh/complete Module,  Prev: The zsh/clone Module,  Up: Zsh Modules

22.5 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 *note
Completion Using compctl::.  The other builtin command, compcall can be
used in user-defined completion widgets, see *note Completion Widgets::.


File: zsh.info,  Node: The zsh/complete Module,  Next: The zsh/complist Module,  Prev: The zsh/compctl Module,  Up: Zsh Modules

22.6 The zsh/complete Module
============================

The zsh/complete module makes available several builtin commands which
can be used in user-defined completion widgets, see *note Completion
Widgets::.


File: zsh.info,  Node: The zsh/complist Module,  Next: The zsh/computil Module,  Prev: The zsh/complete Module,  Up: Zsh Modules

22.7 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.

22.7.1 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 *note Other Functions::).  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 *note Completion
System Configuration::).

22.7.2 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.

22.7.3 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 *note Options::).

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 *note Zsh Line Editor::.

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 *note The zsh/zle Module::).  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.


File: zsh.info,  Node: The zsh/computil Module,  Next: The zsh/curses Module,  Prev: The zsh/complist Module,  Up: Zsh Modules

22.8 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 *note Completion System:: ).  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.


File: zsh.info,  Node: The zsh/curses Module,  Next: The zsh/datetime Module,  Prev: The zsh/computil Module,  Up: Zsh Modules

22.9 The zsh/curses Module
==========================

The zsh/curses module makes available one builtin command and various
parameters.

22.9.1 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.

22.9.2 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'.


File: zsh.info,  Node: The zsh/datetime Module,  Next: The zsh/db/gdbm Module,  Prev: The zsh/curses Module,  Up: Zsh Modules

22.10 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 *note
     Prompt Expansion:: 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


File: zsh.info,  Node: The zsh/db/gdbm Module,  Next: The zsh/deltochar Module,  Prev: The zsh/datetime Module,  Up: Zsh Modules

22.11 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.


File: zsh.info,  Node: The zsh/deltochar Module,  Next: The zsh/example Module,  Prev: The zsh/db/gdbm Module,  Up: Zsh Modules

22.12 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.


File: zsh.info,  Node: The zsh/example Module,  Next: The zsh/files Module,  Prev: The zsh/deltochar Module,  Up: Zsh Modules

22.13 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.


File: zsh.info,  Node: The zsh/files Module,  Next: The zsh/langinfo Module,  Prev: The zsh/example Module,  Up: Zsh Modules

22.14 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.


File: zsh.info,  Node: The zsh/langinfo Module,  Next: The zsh/mapfile Module,  Prev: The zsh/files Module,  Up: Zsh Modules

22.15 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


File: zsh.info,  Node: The zsh/mapfile Module,  Next: The zsh/mathfunc Module,  Prev: The zsh/langinfo Module,  Up: Zsh Modules

22.16 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'}}")'.

22.16.1 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.


File: zsh.info,  Node: The zsh/mathfunc Module,  Next: The zsh/nearcolor Module,  Prev: The zsh/mapfile Module,  Up: Zsh Modules

22.17 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 *note Mathematical
Functions::.

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().


File: zsh.info,  Node: The zsh/nearcolor Module,  Next: The zsh/newuser Module,  Prev: The zsh/mathfunc Module,  Up: Zsh Modules

22.18 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.


File: zsh.info,  Node: The zsh/newuser Module,  Next: The zsh/parameter Module,  Prev: The zsh/nearcolor Module,  Up: Zsh Modules

22.19 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 *note User Configuration Functions::.


File: zsh.info,  Node: The zsh/parameter Module,  Next: The zsh/pcre Module,  Prev: The zsh/newuser Module,  Up: Zsh Modules

22.20 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
     *note Parameter Expansion:: .  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.


File: zsh.info,  Node: The zsh/pcre Module,  Next: The zsh/param/private Module,  Prev: The zsh/parameter Module,  Up: Zsh Modules

22.21 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.


File: zsh.info,  Node: The zsh/param/private Module,  Next: The zsh/regex Module,  Prev: The zsh/pcre Module,  Up: Zsh Modules

22.22 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 (*note Shell Builtin Commands::) 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 (*note Options::).  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:

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


File: zsh.info,  Node: The zsh/regex Module,  Next: The zsh/sched Module,  Prev: The zsh/param/private Module,  Up: Zsh Modules

22.23 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.


File: zsh.info,  Node: The zsh/sched Module,  Next: The zsh/net/socket Module,  Prev: The zsh/regex Module,  Up: Zsh Modules

22.24 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 *note
     The zsh/datetime Module::.

     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 *note 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.


File: zsh.info,  Node: The zsh/net/socket Module,  Next: The zsh/stat Module,  Prev: The zsh/sched Module,  Up: Zsh Modules

22.25 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.

22.25.1 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}>&-

22.25.2 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.


File: zsh.info,  Node: The zsh/stat Module,  Next: The zsh/system Module,  Prev: The zsh/net/socket Module,  Up: Zsh Modules

22.26 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 *note Prompt
          Expansion::.  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.


File: zsh.info,  Node: The zsh/system Module,  Next: The zsh/net/tcp Module,  Prev: The zsh/stat Module,  Up: Zsh Modules

22.27 The zsh/system Module
===========================

The zsh/system module makes available various builtin commands and
parameters.

22.27.1 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).

22.27.2 Math Functions
----------------------

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

22.27.3 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.


File: zsh.info,  Node: The zsh/net/tcp Module,  Next: The zsh/termcap Module,  Prev: The zsh/system Module,  Up: Zsh Modules

22.28 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.

22.28.1 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.

22.28.2 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.

22.28.3 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 *note The zsh/zftp
     Module:: ) cannot be closed this way.  In order to force such a
     socket closed, use -f.

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

22.28.4 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


File: zsh.info,  Node: The zsh/termcap Module,  Next: The zsh/terminfo Module,  Prev: The zsh/net/tcp Module,  Up: Zsh Modules

22.29 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.


File: zsh.info,  Node: The zsh/terminfo Module,  Next: The zsh/watch Module,  Prev: The zsh/termcap Module,  Up: Zsh Modules

22.30 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.


File: zsh.info,  Node: The zsh/watch Module,  Next: The zsh/zftp Module,  Prev: The zsh/terminfo Module,  Up: Zsh Modules

22.31 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 *note Prompt Expansion::.

     %(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.


File: zsh.info,  Node: The zsh/zftp Module,  Next: The zsh/zle Module,  Prev: The zsh/watch Module,  Up: Zsh Modules

22.32 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 *note Zftp Function System::.  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.

22.32.1 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.

22.32.2 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.

22.32.3 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.

22.32.4 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.


File: zsh.info,  Node: The zsh/zle Module,  Next: The zsh/zleparameter Module,  Prev: The zsh/zftp Module,  Up: Zsh Modules

22.33 The zsh/zle Module
========================

The zsh/zle module contains the Zsh Line Editor.  See *note Zsh Line
Editor::.


File: zsh.info,  Node: The zsh/zleparameter Module,  Next: The zsh/zprof Module,  Prev: The zsh/zle Module,  Up: Zsh Modules

22.34 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 *note
Zsh Line Editor::).

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.


File: zsh.info,  Node: The zsh/zprof Module,  Next: The zsh/zpty Module,  Prev: The zsh/zleparameter Module,  Up: Zsh Modules

22.35 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.


File: zsh.info,  Node: The zsh/zpty Module,  Next: The zsh/zselect Module,  Prev: The zsh/zprof Module,  Up: Zsh Modules

22.36 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 *note Zle
     Builtins::) or manipulated with sysread and syswrite (see *note The
     zsh/system Module::).  _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.


File: zsh.info,  Node: The zsh/zselect Module,  Next: The zsh/zutil Module,  Prev: The zsh/zpty Module,  Up: Zsh Modules

22.37 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(2).
     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.


File: zsh.info,  Node: The zsh/zutil Module,  Prev: The zsh/zselect Module,  Up: Zsh Modules

22.38 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 sequence '%%' can be
     used to produce a literal %.

     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)


File: zsh.info,  Node: Calendar Function System,  Next: TCP Function System,  Prev: Zsh Modules,  Up: Top

23 Calendar Function System
***************************

23.1 Description
================

The shell is supplied with a series of functions to replace and enhance
the traditional Unix calendar programme, which warns the user of
imminent or future events, details of which are stored in a text file
(typically calendar in the user's home directory).  The version provided
here includes a mechanism for alerting the user when an event is due.

In addition functions age, before and after are provided that can be
used in a glob qualifier; they allow files to be selected based on their
modification times.

The format of the calendar file and the dates used there in and in the
age function are described first, then the functions that can be called
to examine and modify the calendar file.

The functions here depend on the availability of the zsh/datetime module
which is usually installed with the shell.  The library function
strptime() must be available; it is present on most recent operating
systems.

* Menu:

* Calendar File and Date Formats::
* Calendar System User Functions::
* Calendar Styles::
* Calendar Utility Functions::
* Calendar Bugs::


File: zsh.info,  Node: Calendar File and Date Formats,  Next: Calendar System User Functions,  Up: Calendar Function System

23.2 File and Date Formats
==========================

23.2.1 Calendar File Format
---------------------------

The calendar file is by default ~/calendar.  This can be configured by
the calendar-file style, see *note Calendar Styles::.  The basic format
consists of a series of separate lines, with no indentation, each
including a date and time specification followed by a description of the
event.

Various enhancements to this format are supported, based on the syntax
of Emacs calendar mode.  An indented line indicates a continuation line
that continues the description of the event from the preceding line
(note the date may not be continued in this way).  An initial ampersand
(&) is ignored for compatibility.

An indented line on which the first non-whitespace character is # is not
displayed with the calendar entry, but is still scanned for information.
This can be used to hide information useful to the calendar system but
not to the user, such as the unique identifier used by calendar_add.

The Emacs extension that a date with no description may refer to a
number of succeeding events at different times is not supported.

Unless the done-file style has been altered, any events which have been
processed are appended to the file with the same name as the calendar
file with the suffix .done, hence ~/calendar.done by default.

An example is shown below.

23.2.2 Date Format
------------------

The format of the date and time is designed to allow flexibility without
admitting ambiguity.  (The words 'date' and 'time' are both used in the
documentation below; except where specifically noted this implies a
string that may include both a date and a time specification.)  Note
that there is no localization support; month and day names must be in
English and separator characters are fixed.  Matching is case
insensitive, and only the first three letters of the names are
significant, although as a special case a form beginning "month" does
not match "Monday".  Furthermore, time zones are not handled; all times
are assumed to be local.

It is recommended that, rather than exploring the intricacies of the
system, users find a date format that is natural to them and stick to
it.  This will avoid unexpected effects.  Various key facts should be
noted.

   • In particular, note the confusion between MONTH/DAY/YEAR and
     DAY/MONTH/YEAR when the month is numeric; these formats should be
     avoided if at all possible.  Many alternatives are available.
   • The year must be given in full to avoid confusion, and only years
     from 1900 to 2099 inclusive are matched.

The following give some obvious examples; users finding here a format
they like and not subject to vagaries of style may skip the full
description.  As dates and times are matched separately (even though the
time may be embedded in the date), any date format may be mixed with any
format for the time of day provide the separators are clear (whitespace,
colons, commas).

     2007/04/03 13:13
     2007/04/03:13:13
     2007/04/03 1:13 pm
     3rd April 2007, 13:13
     April 3rd 2007 1:13 p.m.
     Apr 3, 2007 13:13
     Tue Apr 03 13:13:00 2007
     13:13 2007/apr/3

More detailed rules follow.

Times are parsed and extracted before dates.  They must use colons to
separate hours and minutes, though a dot is allowed before seconds if
they are present.  This limits time formats to the following:

   • HH:MM[:SS[.FFFFF]] [am|pm|a.m.|p.m.]
   • HH:MM.SS[.FFFFF] [am|pm|a.m.|p.m.]

Here, square brackets indicate optional elements, possibly with
alternatives.  Fractions of a second are recognised but ignored.  For
absolute times (the normal format require by the calendar file and the
age, before and after functions) a date is mandatory but a time of day
is not; the time returned is at the start of the date.  One variation is
allowed: if a.m. or p.m. or one of their variants is present, an hour
without a minute is allowed, e.g.  3 p.m..

Time zones are not handled, though if one is matched following a time
specification it will be removed to allow a surrounding date to be
parsed.  This only happens if the format of the timezone is not too
unusual.  The following are examples of forms that are understood:

     +0100
     GMT
     GMT-7
     CET+1CDT

Any part of the timezone that is not numeric must have exactly three
capital letters in the name.

Dates suffer from the ambiguity between DD/MM/YYYY and MM/DD/YYYY.  It
is recommended this form is avoided with purely numeric dates, but use
of ordinals, eg.  3rd/04/2007, will resolve the ambiguity as the ordinal
is always parsed as the day of the month.  Years must be four digits
(and the first two must be 19 or 20); 03/04/08 is not recognised.  Other
numbers may have leading zeroes, but they are not required.  The
following are handled:

   • YYYY/MM/DD
   • YYYY-MM-DD
   • YYYY/MNM/DD
   • YYYY-MNM-DD
   • DD[th|st|rd] MNM[,] [ YYYY ]
   • MNM DD[th|st|rd][,] [ YYYY ]
   • DD[th|st|rd]/MM[,] YYYY
   • DD[th|st|rd]/MM/YYYY
   • MM/DD[th|st|rd][,] YYYY
   • MM/DD[th|st|rd]/YYYY

Here, MNM is at least the first three letters of a month name, matched
case-insensitively.  The remainder of the month name may appear but its
contents are irrelevant, so janissary, febrile, martial, apricot, maybe,
junta, etc.  are happily handled.

Where the year is shown as optional, the current year is assumed.  There
are only two such cases, the form Jun 20 or 14 September (the only two
commonly occurring forms, apart from a "the" in some forms of English,
which isn't currently supported).  Such dates will of course become
ambiguous in the future, so should ideally be avoided.

Times may follow dates with a colon, e.g.  1965/07/12:09:45; this is in
order to provide a format with no whitespace.  A comma and whitespace
are allowed, e.g.  1965/07/12, 09:45.  Currently the order of these
separators is not checked, so illogical formats such as 1965/07/12, :
,09:45 will also be matched.  For simplicity such variations are not
shown in the list above.  Otherwise, a time is only recognised as being
associated with a date if there is only whitespace in between, or if the
time was embedded in the date.

Days of the week are not normally scanned, but will be ignored if they
occur at the start of the date pattern only.  However, in contexts where
it is useful to specify dates relative to today, days of the week with
no other date specification may be given.  The day is assumed to be
either today or within the past week.  Likewise, the words yesterday,
today and tomorrow are handled.  All matches are case-insensitive.
Hence if today is Monday, then Sunday is equivalent to yesterday, Monday
is equivalent to today, but Tuesday gives a date six days ago.  This is
not generally useful within the calendar file.  Dates in this format may
be combined with a time specification; for example Tomorrow, 8 p.m..

For example, the standard date format:

     Fri Aug 18 17:00:48 BST 2006

is handled by matching HH:MM:SS and removing it together with the
matched (but unused) time zone.  This leaves the following:

     Fri Aug 18 2006

Fri is ignored and the rest is matched according to the standard rules.

23.2.3 Relative Time Format
---------------------------

In certain places relative times are handled.  Here, a date is not
allowed; instead a combination of various supported periods are allowed,
together with an optional time.  The periods must be in order from most
to least significant.

In some cases, a more accurate calculation is possible when there is an
anchor date: offsets of months or years pick the correct day, rather
than being rounded, and it is possible to pick a particular day in a
month as '(1st Friday)', etc., as described in more detail below.

Anchors are available in the following cases.  If one or two times are
passed to the function calendar, the start time acts an anchor for the
end time when the end time is relative (even if the start time is
implicit).  When examining calendar files, the scheduled event being
examined anchors the warning time when it is given explicitly by means
of the WARN keyword; likewise, the scheduled event anchors a repetition
period when given by the RPT keyword, so that specifications such as RPT
2 months, 3rd Thursday are handled properly.  Finally, the -R argument
to calendar_scandate directly provides an anchor for relative
calculations.

The periods handled, with possible abbreviations are:

Years
     years, yrs, ys, year, yr, y, yearly.  A year is 365.25 days unless
     there is an anchor.

Months
     months, mons, mnths, mths, month, mon, mnth, mth, monthly.  Note
     that m, ms, mn, mns are ambiguous and are _not_ handled.  A month
     is a period of 30 days rather than a calendar month unless there is
     an anchor.

Weeks
     weeks, wks, ws, week, wk, w, weekly

Days
     days, dys, ds, day, dy, d, daily

Hours
     hours, hrs, hs, hour, hr, h, hourly

Minutes
     minutes, mins, minute, min, but _not_ m, ms, mn or mns

Seconds
     seconds, secs, ss, second, sec, s

Spaces between the numbers are optional, but are required between items,
although a comma may be used (with or without spaces).

The forms yearly to hourly allow the number to be omitted; it is assumed
to be 1.  For example, 1 d and daily are equivalent.  Note that using
those forms with plurals is confusing; 2 yearly is the same as 2 years,
_not_ twice yearly, so it is recommended they only be used without
numbers.

When an anchor time is present, there is an extension to handle regular
events in the form of the Nth SOMEday of the month.  Such a
specification must occur immediately after any year and month
specification, but before any time of day, and must be in the form
N(th|st|rd) DAY, for example 1st Tuesday or 3rd Monday.  As in other
places, days are matched case insensitively, must be in English, and
only the first three letters are significant except that a form
beginning 'month' does not match 'Monday'.  No attempt is made to
sanitize the resulting date; attempts to squeeze too many occurrences
into a month will push the day into the next month (but in the obvious
fashion, retaining the correct day of the week).

Here are some examples:

     30 years 3 months 4 days 3:42:41
     14 days 5 hours
     Monthly, 3rd Thursday
     4d,10hr

23.2.4 Example
--------------

Here is an example calendar file.  It uses a consistent date format, as
recommended above.

     Feb 1, 2006 14:30 Pointless bureaucratic meeting
     Mar 27, 2006 11:00 Mutual recrimination and finger pointing
       Bring water pistol and waterproofs
     Mar 31, 2006 14:00 Very serious managerial pontification
       # UID 12C7878A9A50
     Apr 10, 2006 13:30 Even more pointless blame assignment exercise WARN 30 mins
     May 18, 2006 16:00 Regular moaning session RPT monthly, 3rd Thursday

The second entry has a continuation line.  The third entry has a
continuation line that will not be shown when the entry is displayed,
but the unique identifier will be used by the calendar_add function when
updating the event.  The fourth entry will produce a warning 30 minutes
before the event (to allow you to equip yourself appropriately).  The
fifth entry repeats after a month on the 3rd Thursday, i.e.  June 15,
2006, at the same time.


File: zsh.info,  Node: Calendar System User Functions,  Next: Calendar Styles,  Prev: Calendar File and Date Formats,  Up: Calendar Function System

23.3 User Functions
===================

This section describes functions that are designed to be called directly
by the user.  The first part describes those functions associated with
the user's calendar; the second part describes the use in glob
qualifiers.

23.3.1 Calendar system functions
--------------------------------

calendar [ -abdDsv ] [ -C CALFILE ] [ -n NUM ] [ -S SHOWPROG ]
         [ [ START ] END ]
calendar -r [ -abdDrsv ] [ -C CALFILE ] [ -n NUM ] [ -S SHOWPROG ]
         [ START ]
     Show events in the calendar.

     With no arguments, show events from the start of today until the
     end of the next working day after today.  In other words, if today
     is Friday, Saturday, or Sunday, show up to the end of the following
     Monday, otherwise show today and tomorrow.

     If END is given, show events from the start of today up to the time
     and date given, which is in the format described in the previous
     section.  Note that if this is a date the time is assumed to be
     midnight at the start of the date, so that effectively this shows
     all events before the given date.

     END may start with a +, in which case the remainder of the
     specification is a relative time format as described in the
     previous section indicating the range of time from the start time
     that is to be included.

     If START is also given, show events starting from that time and
     date.  The word now can be used to indicate the current time.

     To implement an alert when events are due, include calendar -s in
     your ~/.zshrc file.

     Options:

     -a
          Show all items in the calendar, regardless of the start and
          end.

     -b
          Brief: don't display continuation lines (i.e.  indented lines
          following the line with the date/time), just the first line.

     -B LINES
          Brief: display at most the first LINES lines of the calendar
          entry.  '-B 1' is equivalent to '-b'.

     -C CALFILE
          Explicitly specify a calendar file instead of the value of the
          calendar-file style or the default ~/calendar.

     -d
          Move any events that have passed from the calendar file to the
          "done" file, as given by the done-file style or the default
          which is the calendar file with .done appended.  This option
          is implied by the -s option.

     -D
          Turns off the option -d, even if the -s option is also
          present.

     -n NUM, -NUM
          Show at least NUM events, if present in the calendar file,
          regardless of the start and end.

     -r
          Show all the remaining options in the calendar, ignoring the
          given END time.  The START time is respected; any argument
          given is treated as a START time.

     -s
          Use the shell's sched command to schedule a timed event that
          will warn the user when an event is due.  Note that the sched
          command only runs if the shell is at an interactive prompt; a
          foreground task blocks the scheduled task from running until
          it is finished.

          The timed event usually runs the programme calendar_show to
          show the event, as described in *note Calendar Utility
          Functions::.

          By default, a warning of the event is shown five minutes
          before it is due.  The warning period can be configured by the
          style warn-time or for a single calendar entry by including
          WARN RELTIME in the first line of the entry, where RELTIME is
          one of the usual relative time formats.

          A repeated event may be indicated by including RPT RELDATE in
          the first line of the entry.  After the scheduled event has
          been displayed it will be re-entered into the calendar file at
          a time RELDATE after the existing event.  Note that this is
          currently the only use made of the repeat count, so that it is
          not possible to query the schedule for a recurrence of an
          event in the calendar until the previous event has passed.

          If RPT is used, it is also possible to specify that certain
          recurrences of an event are rescheduled or cancelled.  This is
          done with the OCCURRENCE keyword, followed by whitespace and
          the date and time of the occurrence in the regular sequence,
          followed by whitespace and either the date and time of the
          rescheduled event or the exact string CANCELLED.  In this case
          the date and time must be in exactly the "date with local
          time" format used by the text/calendar MIME type (RFC 2445),
          <YYYY><MM><DD>T<HH><MM><SS> (note the presence of the literal
          character T).  The first word (the regular recurrence) may be
          something other than a proper date/time to indicate that the
          event is additional to the normal sequence; a convention that
          retains the formatting appearance is XXXXXXXXTXXXXXX.

          Furthermore, it is useful to record the next regular
          recurrence (as then the displayed date may be for a
          rescheduled event so cannot be used for calculating the
          regular sequence).  This is specified by RECURRENCE and a time
          or date in the same format.  calendar_add adds such an
          indication when it encounters a recurring event that does not
          include one, based on the headline date/time.

          If calendar_add is used to update occurrences the UID keyword
          described there should be present in both the existing entry
          and the added occurrence in order to identify recurring event
          sequences.

          For example,

               Thu May 6, 2010 11:00 Informal chat RPT 1 week
                 # RECURRENCE 20100506T110000
                 # OCCURRENCE 20100513T110000 20100513T120000
                 # OCCURRENCE 20100520T110000 CANCELLED

          The event that occurs at 11:00 on 13th May 2010 is rescheduled
          an hour later.  The event that occurs a week later is
          cancelled.  The occurrences are given on a continuation line
          starting with a # character so will not usually be displayed
          as part of the event.  As elsewhere, no account of time zones
          is taken with the times.  After the next event occurs the
          headline date/time will be 'Thu May 13, 2010 12:00' while the
          RECURRENCE date/time will be '20100513T110000' (note that
          cancelled and moved events are not taken account of in the
          RECURRENCE, which records what the next regular recurrence is,
          but they are accounted for in the headline date/time).

          It is safe to run calendar -s to reschedule an existing event
          (if the calendar file has changed, for example), and also to
          have it running in multiples instances of the shell since the
          calendar file is locked when in use.

          By default, expired events are moved to the "done" file; see
          the -d option.  Use -D to prevent this.

     -S SHOWPROG
          Explicitly specify a programme to be used for showing events
          instead of the value of the show-prog style or the default
          calendar_show.

     -v
          Verbose: show more information about stages of processing.
          This is useful for confirming that the function has
          successfully parsed the dates in the calendar file.

calendar_add [ -BL ] EVENT ...
     Adds a single event to the calendar in the appropriate location.
     The event can contain multiple lines, as described in *note
     Calendar File and Date Formats::.  Using this function ensures that
     the calendar file is sorted in date and time order.  It also makes
     special arrangements for locking the file while it is altered.  The
     old calendar is left in a file with the suffix .old.

     The option -B indicates that backing up the calendar file will be
     handled by the caller and should not be performed by calendar_add.
     The option -L indicates that calendar_add does not need to lock the
     calendar file as it is already locked.  These options will not
     usually be needed by users.

     If the style reformat-date is true, the date and time of the new
     entry will be rewritten into the standard date format: see the
     descriptions of this style and the style date-format.

     The function can use a unique identifier stored with each event to
     ensure that updates to existing events are treated correctly.  The
     entry should contain the word UID, followed by whitespace, followed
     by a word consisting entirely of hexadecimal digits of arbitrary
     length (all digits are significant, including leading zeroes).  As
     the UID is not directly useful to the user, it is convenient to
     hide it on an indented continuation line starting with a #, for
     example:

          Aug 31, 2007 09:30  Celebrate the end of the holidays
            # UID 045B78A0

     The second line will not be shown by the calendar function.

     It is possible to specify the RPT keyword followed by CANCELLED
     instead of a relative time.  This causes any matched event or
     series of events to be cancelled (the original event does not have
     to be marked as recurring in order to be cancelled by this method).
     A UID is required in order to match an existing event in the
     calendar.

     calendar_add will attempt to manage recurrences and occurrences of
     repeating events as described for event scheduling by calendar -s
     above.  To reschedule or cancel a single event calendar_add should
     be called with an entry that includes the correct UID but does
     _not_ include the RPT keyword as this is taken to mean the entry
     applies to a series of repeating events and hence replaces all
     existing information.  Each rescheduled or cancelled occurrence
     must have an OCCURRENCE keyword in the entry passed to calendar_add
     which will be merged into the calendar file.  Any existing
     reference to the occurrence is replaced.  An occurrence that does
     not refer to a valid existing event is added as a one-off
     occurrence to the same calendar entry.

calendar_edit
     This calls the user's editor to edit the calendar file.  If there
     are arguments, they are taken as the editor to use (the file name
     is appended to the commands); otherwise, the editor is given by the
     variable VISUAL, if set, else the variable EDITOR.

     If the calendar scheduler was running, then after editing the file
     calendar -s is called to update it.

     This function locks out the calendar system during the edit.  Hence
     it should be used to edit the calendar file if there is any
     possibility of a calendar event occurring meanwhile.  Note this can
     lead to another shell with calendar functions enabled hanging
     waiting for a lock, so it is necessary to quit the editor as soon
     as possible.

calendar_parse CALENDAR-ENTRY
     This is the internal function that analyses the parts of a calendar
     entry, which is passed as the only argument.  The function returns
     status 1 if the argument could not be parsed as a calendar entry
     and status 2 if the wrong number of arguments were passed; it also
     sets the parameter reply to an empty associative array.  Otherwise,
     it returns status 0 and sets elements of the associative array
     reply as follows:

     time
          The time as a string of digits in the same units as
          $EPOCHSECONDS
     schedtime
          The regularly scheduled time.  This may differ from the actual
          event time time if this is a recurring event and the next
          occurrence has been rescheduled.  Then time gives the actual
          time and schedtime the time of the regular recurrence before
          modification.
     text1
          The text from the line not including the date and time of the
          event, but including any WARN or RPT keywords and values.
     warntime
          Any warning time given by the WARN keyword as a string of
          digits containing the time at which to warn in the same units
          as $EPOCHSECONDS.  (Note this is an absolute time, not the
          relative time passed down.)  Not set no WARN keyword and value
          were matched.
     warnstr
          The raw string matched after the WARN keyword, else unset.
     rpttime
          Any recurrence time given by the RPT keyword as a string of
          digits containing the time of the recurrence in the same units
          as $EPOCHSECONDS.  (Note this is an absolute time.)  Not set
          if no RPT keyword and value were matched.
     schedrpttime
          The next regularly scheduled occurrence of a recurring event
          before modification.  This may differ from rpttime, which is
          the actual time of the event that may have been rescheduled
          from the regular time.
     rptstr
          The raw string matched after the RPT keyword, else unset.
     text2
          The text from the line after removal of the date and any
          keywords and values.

calendar_showdate [ -r ] [ -f FMT ] DATE-SPEC ...
     The given DATE-SPEC is interpreted and the corresponding date and
     time printed.  If the initial DATE-SPEC begins with a + or - it is
     treated as relative to the current time; DATE-SPECs after the first
     are treated as relative to the date calculated so far and a leading
     + is optional in that case.  This allows one to use the system as a
     date calculator.  For example, calendar_showdate '+1 month, 1st
     Friday' shows the date of the first Friday of next month.

     With the option -r nothing is printed but the value of the date and
     time in seconds since the epoch is stored in the parameter REPLY.

     With the option -f FMT the given date/time conversion format is
     passed to strftime; see notes on the date-format style below.

     In order to avoid ambiguity with negative relative date
     specifications, options must occur in separate words; in other
     words, -r and -f should not be combined in the same word.

calendar_sort
     Sorts the calendar file into date and time order.  The old calendar
     is left in a file with the suffix .old.

23.3.2 Glob qualifiers
----------------------

age
     The function age can be autoloaded and use separately from the
     calendar system, although it uses the function calendar_scandate
     for date formatting.  It requires the zsh/stat builtin, but uses
     only the builtin zstat.

     age selects files having a given modification time for use as a
     glob qualifier.  The format of the date is the same as that
     understood by the calendar system, described in *note Calendar File
     and Date Formats::.

     The function can take one or two arguments, which can be supplied
     either directly as command or arguments, or separately as shell
     parameters.

          print *(e:age 2006/10/04 2006/10/09:)

     The example above matches all files modified between the start of
     those dates.  The second argument may alternatively be a relative
     time introduced by a +:

          print *(e:age 2006/10/04 +5d:)

     The example above is equivalent to the previous example.

     In addition to the special use of days of the week, today and
     yesterday, times with no date may be specified; these apply to
     today.  Obviously such uses become problematic around midnight.

          print *(e-age 12:00 13:30-)

     The example above shows files modified between 12:00 and 13:00
     today.

          print *(e:age 2006/10/04:)

     The example above matches all files modified on that date.  If the
     second argument is omitted it is taken to be exactly 24 hours after
     the first argument (even if the first argument contains a time).

          print *(e-age 2006/10/04:10:15 2006/10/04:10:45-)

     The example above supplies times.  Note that whitespace within the
     time and date specification must be quoted to ensure age receives
     the correct arguments, hence the use of the additional colon to
     separate the date and time.

          AGEREF=2006/10/04:10:15
          AGEREF2=2006/10/04:10:45
          print *(+age)

     This shows the same example before using another form of argument
     passing.  The dates and times in the parameters AGEREF and AGEREF2
     stay in effect until unset, but will be overridden if any argument
     is passed as an explicit argument to age.  Any explicit argument
     causes both parameters to be ignored.

     Instead of an explicit date and time, it's possible to use the
     modification time of a file as the date and time for either
     argument by introducing the file name with a colon:

          print *(e-age :file1-)

     matches all files created on the same day (24 hours starting from
     midnight) as file1.

          print *(e-age :file1 :file2-)

     matches all files modified no earlier than file1 and no later than
     file2; precision here is to the nearest second.

after
before
     The functions after and before are simpler versions of age that
     take just one argument.  The argument is parsed similarly to an
     argument of age; if it is not given the variable AGEREF is
     consulted.  As the names of the functions suggest, a file matches
     if its modification time is after or before the time and date
     specified.  If a time only is given the date is today.

     The two following examples are therefore equivalent:
          print *(e-after 12:00-)
          print *(e-after today:12:00-)


File: zsh.info,  Node: Calendar Styles,  Next: Calendar Utility Functions,  Prev: Calendar System User Functions,  Up: Calendar Function System

23.4 Styles
===========

The zsh style mechanism using the zstyle command is describe in *note
The zsh/zutil Module::.  This is the same mechanism used in the
completion system.

The styles below are all examined in the context :datetime:FUNCTION:,
for example :datetime:calendar:.

calendar-file
     The location of the main calendar.  The default is ~/calendar.

date-format
     A strftime format string (see strftime(3)) with the zsh extensions
     providing various numbers with no leading zero or space if the
     number is a single digit as described for the %D{STRING} prompt
     format in *note Prompt Expansion::.

     This is used for outputting dates in calendar, both to support the
     -v option and when adding recurring events back to the calendar
     file, and in calendar_showdate as the final output format.

     If the style is not set, the default used is similar the standard
     system format as output by the date command (also known as 'ctime
     format'): '%a %b %d %H:%M:%S %Z %Y'.

done-file
     The location of the file to which events which have passed are
     appended.  The default is the calendar file location with the
     suffix .done.  The style may be set to an empty string in which
     case a "done" file will not be maintained.

reformat-date
     Boolean, used by calendar_add.  If it is true, the date and time of
     new entries added to the calendar will be reformatted to the format
     given by the style date-format or its default.  Only the date and
     time of the event itself is reformatted; any subsidiary dates and
     times such as those associated with repeat and warning times are
     left alone.

show-prog
     The programme run by calendar for showing events.  It will be
     passed the start time and stop time of the events requested in
     seconds since the epoch followed by the event text.  Note that
     calendar -s uses a start time and stop time equal to one another to
     indicate alerts for specific events.

     The default is the function calendar_show.

warn-time
     The time before an event at which a warning will be displayed, if
     the first line of the event does not include the text EVENT
     RELTIME.  The default is 5 minutes.


File: zsh.info,  Node: Calendar Utility Functions,  Next: Calendar Bugs,  Prev: Calendar Styles,  Up: Calendar Function System

23.5 Utility functions
======================

calendar_lockfiles
     Attempt to lock the files given in the argument.  To prevent
     problems with network file locking this is done in an ad hoc
     fashion by attempting to create a symbolic link to the file with
     the name FILE.lockfile.  No other system level functions are used
     for locking, i.e.  the file can be accessed and modified by any
     utility that does not use this mechanism.  In particular, the user
     is not prevented from editing the calendar file at the same time
     unless calendar_edit is used.

     Three attempts are made to lock the file before giving up.  If the
     module zsh/zselect is available, the times of the attempts are
     jittered so that multiple instances of the calling function are
     unlikely to retry at the same time.

     The files locked are appended to the array lockfiles, which should
     be local to the caller.

     If all files were successfully locked, status zero is returned,
     else status one.

     This function may be used as a general file locking function,
     although this will only work if only this mechanism is used to lock
     files.

calendar_read
     This is a backend used by various other functions to parse the
     calendar file, which is passed as the only argument.  The array
     calendar_entries is set to the list of events in the file; no
     pruning is done except that ampersands are removed from the start
     of the line.  Each entry may contain multiple lines.

calendar_scandate
     This is a generic function to parse dates and times that may be
     used separately from the calendar system.  The argument is a date
     or time specification as described in *note Calendar File and Date
     Formats::.  The parameter REPLY is set to the number of seconds
     since the epoch corresponding to that date or time.  By default,
     the date and time may occur anywhere within the given argument.

     Returns status zero if the date and time were successfully parsed,
     else one.

     Options:
     -a
          The date and time are anchored to the start of the argument;
          they will not be matched if there is preceding text.

     -A
          The date and time are anchored to both the start and end of
          the argument; they will not be matched if the is any other
          text in the argument.

     -d
          Enable additional debugging output.

     -m
          Minus.  When -R ANCHOR_TIME is also given the relative time is
          calculated backwards from ANCHOR_TIME.

     -r
          The argument passed is to be parsed as a relative time.

     -R ANCHOR_TIME
          The argument passed is to be parsed as a relative time.  The
          time is relative to ANCHOR_TIME, a time in seconds since the
          epoch, and the returned value is the absolute time
          corresponding to advancing ANCHOR_TIME by the relative time
          given.  This allows lengths of months to be correctly taken
          into account.  If the final day does not exist in the given
          month, the last day of the final month is given.  For example,
          if the anchor time is during 31st January 2007 and the
          relative time is 1 month, the final time is the same time of
          day during 28th February 2007.

     -s
          In addition to setting REPLY, set REPLY2 to the remainder of
          the argument after the date and time have been stripped.  This
          is empty if the option -A was given.

     -t
          Allow a time with no date specification.  The date is assumed
          to be today.  The behaviour is unspecified if the iron tongue
          of midnight is tolling twelve.

calendar_show
     The function used by default to display events.  It accepts a start
     time and end time for events, both in epoch seconds, and an event
     description.

     The event is always printed to standard output.  If the command
     line editor is active (which will usually be the case) the command
     line will be redisplayed after the output.

     If the parameter DISPLAY is set and the start and end times are the
     same (indicating a scheduled event), the function uses the command
     xmessage to display a window with the event details.


File: zsh.info,  Node: Calendar Bugs,  Prev: Calendar Utility Functions,  Up: Calendar Function System

23.6 Bugs
=========

As the system is based entirely on shell functions (with a little
support from the zsh/datetime module) the mechanisms used are not as
robust as those provided by a dedicated calendar utility.  Consequently
the user should not rely on the shell for vital alerts.

There is no calendar_delete function.

There is no localization support for dates and times, nor any support
for the use of time zones.

Relative periods of months and years do not take into account the
variable number of days.

The calendar_show function is currently hardwired to use xmessage for
displaying alerts on X Window System displays.  This should be
configurable and ideally integrate better with the desktop.

calendar_lockfiles hangs the shell while waiting for a lock on a file.
If called from a scheduled task, it should instead reschedule the event
that caused it.


File: zsh.info,  Node: TCP Function System,  Next: Zftp Function System,  Prev: Calendar Function System,  Up: Top

24 TCP Function System
**********************

24.1 Description
================

A module zsh/net/tcp is provided to provide network I/O over TCP/IP from
within the shell; see its description in *note Zsh Modules::.  This
manual page describes a function suite based on the module.  If the
module is installed, the functions are usually installed at the same
time, in which case they will be available for autoloading in the
default function search path.  In addition to the zsh/net/tcp module,
the zsh/zselect module is used to implement timeouts on read operations.
For troubleshooting tips, consult the corresponding advice for the zftp
functions described in *note Zftp Function System::.

There are functions corresponding to the basic I/O operations open,
close, read and send, named tcp_open etc., as well as a function
tcp_expect for pattern match analysis of data read as input.  The system
makes it easy to receive data from and send data to multiple named
sessions at once.  In addition, it can be linked with the shell's line
editor in such a way that input data is automatically shown at the
terminal.  Other facilities available including logging, filtering and
configurable output prompts.

To use the system where it is available, it should be enough to
'autoload -U tcp_open' and run tcp_open as documented below to start a
session.  The tcp_open function will autoload the remaining functions.

* Menu:

* TCP Functions::
* TCP Parameters::
* TCP Examples::
* TCP Bugs::


File: zsh.info,  Node: TCP Functions,  Next: TCP Parameters,  Up: TCP Function System

24.2 TCP User Functions
=======================

24.2.1 Basic I/O
----------------

tcp_open [ -qz ] HOST PORT [ SESS ]
tcp_open [ -qz ] [ -s SESS | -l SESS[,...] ] ...
tcp_open [ -qz ] [ -a FD | -f FD ] [ SESS ]
     Open a new session.  In the first and simplest form, open a TCP
     connection to host HOST at port PORT; numeric and symbolic forms
     are understood for both.

     If SESS is given, this becomes the name of the session which can be
     used to refer to multiple different TCP connections.  If SESS is
     not given, the function will invent a numeric name value (note this
     is _not_ the same as the file descriptor to which the session is
     attached).  It is recommended that session names not include
     'funny' characters, where funny characters are not well-defined but
     certainly do not include alphanumerics or underscores, and
     certainly do include whitespace.

     In the second case, one or more sessions to be opened are given by
     name.  A single session name is given after -s and a
     comma-separated list after -l; both options may be repeated as many
     times as necessary.  A failure to open any session causes tcp_open
     to abort.  The host and port are read from the file .ztcp_sessions
     in the same directory as the user's zsh initialisation files, i.e.
     usually the home directory, but $ZDOTDIR if that is set.  The file
     consists of lines each giving a session name and the corresponding
     host and port, in that order (note the session name comes first,
     not last), separated by whitespace.

     The third form allows passive and fake TCP connections.  If the
     option -a is used, its argument is a file descriptor open for
     listening for connections.  No function front-end is provided to
     open such a file descriptor, but a call to 'ztcp -l PORT' will
     create one with the file descriptor stored in the parameter $REPLY.
     The listening port can be closed with 'ztcp -c FD'.  A call to
     'tcp_open -a FD' will block until a remote TCP connection is made
     to PORT on the local machine.  At this point, a session is created
     in the usual way and is largely indistinguishable from an active
     connection created with one of the first two forms.

     If the option -f is used, its argument is a file descriptor which
     is used directly as if it were a TCP session.  How well the
     remainder of the TCP function system copes with this depends on
     what actually underlies this file descriptor.  A regular file is
     likely to be unusable; a FIFO (pipe) of some sort will work better,
     but note that it is not a good idea for two different sessions to
     attempt to read from the same FIFO at once.

     If the option -q is given with any of the three forms, tcp_open
     will not print informational messages, although it will in any case
     exit with an appropriate status.

     If the line editor (zle) is in use, which is typically the case if
     the shell is interactive, tcp_open installs a handler inside zle
     which will check for new data at the same time as it checks for
     keyboard input.  This is convenient as the shell consumes no CPU
     time while waiting; the test is performed by the operating system.
     Giving the option -z to any of the forms of tcp_open prevents the
     handler from being installed, so data must be read explicitly.
     Note, however, this is not necessary for executing complete sets of
     send and read commands from a function, as zle is not active at
     this point.  Generally speaking, the handler is only active when
     the shell is waiting for input at a command prompt or in the vared
     builtin.  The option has no effect if zle is not active; '[[ -o
     zle]]' will test for this.

     The first session to be opened becomes the current session and
     subsequent calls to tcp_open do not change it.  The current session
     is stored in the parameter $TCP_SESS; see below for more detail
     about the parameters used by the system.

     The function tcp_on_open, if defined, is called when a session is
     opened.  See the description below.

tcp_close [ -qn ] [ -a | -l SESS[,...] | SESS ... ]
     Close the named sessions, or the current session if none is given,
     or all open sessions if -a is given.  The options -l and -s are
     both handled for consistency with tcp_open, although the latter is
     redundant.

     If the session being closed is the current one, $TCP_SESS is unset,
     leaving no current session, even if there are other sessions still
     open.

     If the session was opened with tcp_open -f, the file descriptor is
     closed so long as it is in the range 0 to 9 accessible directly
     from the command line.  If the option -n is given, no attempt will
     be made to close file descriptors in this case.  The -n option is
     not used for genuine ztcp session; the file descriptors are always
     closed with the session.

     If the option -q is given, no informational messages will be
     printed.

tcp_read [ -bdq ] [ -t TO ] [ -T TO ]
         [ -a | -u FD[,...] | -l SESS[,...] | -s SESS ... ]
     Perform a read operation on the current session, or on a list of
     sessions if any are given with -u, -l or -s, or all open sessions
     if the option -a is given.  Any of the -u, -l or -s options may be
     repeated or mixed together.  The -u option specifies a file
     descriptor directly (only those managed by this system are useful),
     the other two specify sessions as described for tcp_open above.

     The function checks for new data available on all the sessions
     listed.  Unless the -b option is given, it will not block waiting
     for new data.  Any one line of data from any of the available
     sessions will be read, stored in the parameter $TCP_LINE, and
     displayed to standard output unless $TCP_SILENT contains a
     non-empty string.  When printed to standard output the string
     $TCP_PROMPT will be shown at the start of the line; the default
     form for this includes the name of the session being read.  See
     below for more information on these parameters.  In this mode,
     tcp_read can be called repeatedly until it returns status 2 which
     indicates all pending input from all specified sessions has been
     handled.

     With the option -b, equivalent to an infinite timeout, the function
     will block until a line is available to read from one of the
     specified sessions.  However, only a single line is returned.

     The option -d indicates that all pending input should be drained.
     In this case tcp_read may process multiple lines in the manner
     given above; only the last is stored in $TCP_LINE, but the complete
     set is stored in the array $tcp_lines.  This is cleared at the
     start of each call to tcp_read.

     The options -t and -T specify a timeout in seconds, which may be a
     floating point number for increased accuracy.  With -t the timeout
     is applied before each line read.  With -T, the timeout applies to
     the overall operation, possibly including multiple read operations
     if the option -d is present; without this option, there is no
     distinction between -t and -T.

     The function does not print informational messages, but if the
     option -q is given, no error message is printed for a non-existent
     session.

     A return status of 2 indicates a timeout or no data to read.  Any
     other non-zero return status indicates some error condition.

     See tcp_log for how to control where data is sent by tcp_read.

tcp_send [ -cnq ] [ -s SESS | -l SESS[,...] ] DATA ...
tcp_send [ -cnq ] -a DATA ...
     Send the supplied data strings to all the specified sessions in
     turn.  The underlying operation differs little from a 'print -r' to
     the session's file descriptor, although it attempts to prevent the
     shell from dying owing to a SIGPIPE caused by an attempt to write
     to a defunct session.

     The option -c causes tcp_send to behave like cat.  It reads lines
     from standard input until end of input and sends them in turn to
     the specified session(s) exactly as if they were given as DATA
     arguments to individual tcp_send commands.

     The option -n prevents tcp_send from putting a newline at the end
     of the data strings.

     The remaining options all behave as for tcp_read.

     The data arguments are not further processed once they have been
     passed to tcp_send; they are simply passed down to print -r.

     If the parameter $TCP_OUTPUT is a non-empty string and logging is
     enabled then the data sent to each session will be echoed to the
     log file(s) with $TCP_OUTPUT in front where appropriate, much in
     the manner of $TCP_PROMPT.

24.2.2 Session Management
-------------------------

tcp_alias [ -q ] ALIAS=SESS ...
tcp_alias [ -q ] [ ALIAS ... ]
tcp_alias -d [ -q ] ALIAS ...
     This function is not particularly well tested.

     The first form creates an alias for a session name; ALIAS can then
     be used to refer to the existing session SESS.  As many aliases may
     be listed as required.

     The second form lists any aliases specified, or all aliases if
     none.

     The third form deletes all the aliases listed.  The underlying
     sessions are not affected.

     The option -q suppresses an inconsistently chosen subset of error
     messages.

tcp_log [ -asc ] [ -n | -N ] [ LOGFILE ]
     With an argument LOGFILE, all future input from tcp_read will be
     logged to the named file.  Unless -a (append) is given, this file
     will first be truncated or created empty.  With no arguments, show
     the current status of logging.

     With the option -s, per-session logging is enabled.  Input from
     tcp_read is output to the file LOGFILE.SESS.  As the session is
     automatically discriminated by the filename, the contents are raw
     (no $TCP_PROMPT).  The option -a applies as above.  Per-session
     logging and logging of all data in one file are not mutually
     exclusive.

     The option -c closes all logging, both complete and per-session
     logs.

     The options -n and -N respectively turn off or restore output of
     data read by tcp_read to standard output; hence 'tcp_log -cn' turns
     off all output by tcp_read.

     The function is purely a convenient front end to setting the
     parameters $TCP_LOG, $TCP_LOG_SESS, $TCP_SILENT, which are
     described below.

tcp_rename OLD NEW
     Rename session OLD to session NEW.  The old name becomes invalid.

tcp_sess [ SESS [ COMMAND [ ARG ... ] ] ]
     With no arguments, list all the open sessions and associated file
     descriptors.  The current session is marked with a star.  For use
     in functions, direct access to the parameters $tcp_by_name,
     $tcp_by_fd and $TCP_SESS is probably more convenient; see below.

     With a SESS argument, set the current session to SESS.  This is
     equivalent to changing $TCP_SESS directly.

     With additional arguments, temporarily set the current session
     while executing 'COMMAND ARG ...'.  COMMAND is re-evaluated so as
     to expand aliases etc., but the remaining ARGs are passed through
     as that appear to tcp_sess.  The original session is restored when
     tcp_sess exits.

24.2.3 Advanced I/O
-------------------

tcp_command SEND-OPTION ... SEND-ARGUMENT ...
     This is a convenient front-end to tcp_send.  All arguments are
     passed to tcp_send, then the function pauses waiting for data.
     While data is arriving at least every $TCP_TIMEOUT (default 0.3)
     seconds, data is handled and printed out according to the current
     settings.  Status 0 is always returned.

     This is generally only useful for interactive use, to prevent the
     display becoming fragmented by output returned from the connection.
     Within a programme or function it is generally better to handle
     reading data by a more explicit method.

tcp_expect [ -q ] [ -p VAR | -P VAR ] [ -t TO | -T TO ]
           [ -a | -s SESS | -l SESS[,...] ] PATTERN ...
     Wait for input matching any of the given PATTERNs from any of the
     specified sessions.  Input is ignored until an input line matches
     one of the given patterns; at this point status zero is returned,
     the matching line is stored in $TCP_LINE, and the full set of lines
     read during the call to tcp_expect is stored in the array
     $tcp_expect_lines.

     Sessions are specified in the same way as tcp_read: the default is
     to use the current session, otherwise the sessions specified by -a,
     -s, or -l are used.

     Each PATTERN is a standard zsh extended-globbing pattern; note that
     it needs to be quoted to avoid it being expanded immediately by
     filename generation.  It must match the full line, so to match a
     substring there must be a '*' at the start and end.  The line
     matched against includes the $TCP_PROMPT added by tcp_read.  It is
     possible to include the globbing flags '#b' or '#m' in the patterns
     to make backreferences available in the parameters $MATCH, $match,
     etc., as described in the base zsh documentation on pattern
     matching.

     Unlike tcp_read, the default behaviour of tcp_expect is to block
     indefinitely until the required input is found.  This can be
     modified by specifying a timeout with -t or -T; these function as
     in tcp_read, specifying a per-read or overall timeout,
     respectively, in seconds, as an integer or floating-point number.
     As tcp_read, the function returns status 2 if a timeout occurs.

     The function returns as soon as any one of the patterns given
     match.  If the caller needs to know which of the patterns matched,
     the option -p VAR can be used; on return, $var is set to the number
     of the pattern using ordinary zsh indexing, i.e.  the first is 1,
     and so on.  Note the absence of a '$' in front of VAR.  To avoid
     clashes, the parameter cannot begin with '_expect'.  The index -1
     is used if there is a timeout and 0 if there is no match.

     The option -P VAR works similarly to -p, but instead of numerical
     indexes the regular arguments must begin with a prefix followed by
     a colon: that prefix is then used as a tag to which VAR is set when
     the argument matches.  The tag timeout is used if there is a
     timeout and the empty string if there is no match.  Note it is
     acceptable for different arguments to start with the same prefix if
     the matches do not need to be distinguished.

     The option -q is passed directly down to tcp_read.

     As all input is done via tcp_read, all the usual rules about output
     of lines read apply.  One exception is that the parameter
     $tcp_lines will only reflect the line actually matched by
     tcp_expect; use $tcp_expect_lines for the full set of lines read
     during the function call.

tcp_proxy
     This is a simple-minded function to accept a TCP connection and
     execute a command with I/O redirected to the connection.  Extreme
     caution should be taken as there is no security whatsoever and this
     can leave your computer open to the world.  Ideally, it should only
     be used behind a firewall.

     The first argument is a TCP port on which the function will listen.

     The remaining arguments give a command and its arguments to execute
     with standard input, standard output and standard error redirected
     to the file descriptor on which the TCP session has been accepted.
     If no command is given, a new zsh is started.  This gives everyone
     on your network direct access to your account, which in many cases
     will be a bad thing.

     The command is run in the background, so tcp_proxy can then accept
     new connections.  It continues to accept new connections until
     interrupted.

tcp_spam [ -ertv ] [ -a | -s SESS | -l SESS[,...] ] CMD [ ARG ... ]
     Execute 'CMD [ ARG ...  ]'  for each session in turn.  Note this
     executes the command and arguments; it does not send the command
     line as data unless the -t (transmit) option is given.

     The sessions may be selected explicitly with the standard -a, -s or
     -l options, or may be chosen implicitly.  If none of the three
     options is given the rules are: first, if the array $tcp_spam_list
     is set, this is taken as the list of sessions, otherwise all
     sessions are taken.  Second, any sessions given in the array
     $tcp_no_spam_list are removed from the list of sessions.

     Normally, any sessions added by the '-a' flag or when all sessions
     are chosen implicitly are spammed in alphabetic order; sessions
     given by the $tcp_spam_list array or on the command line are
     spammed in the order given.  The -r flag reverses the order however
     it was arrived it.

     The -v flag specifies that a $TCP_PROMPT will be output before each
     session.  This is output after any modification to TCP_SESS by the
     user-defined tcp_on_spam function described below.  (Obviously that
     function is able to generate its own output.)

     If the option -e is present, the line given as 'CMD [ ARG ...  ]'
     is executed using eval, otherwise it is executed without any
     further processing.

tcp_talk
     This is a fairly simple-minded attempt to force input to the line
     editor to go straight to the default TCP_SESS.

     An escape string, $TCP_TALK_ESCAPE, default ':', is used to allow
     access to normal shell operation.  If it is on its own at the start
     of the line, or followed only by whitespace, the line editor
     returns to normal operation.  Otherwise, the string and any
     following whitespace are skipped and the remainder of the line
     executed as shell input without any change of the line editor's
     operating mode.

     The current implementation is somewhat deficient in terms of use of
     the command history.  For this reason, many users will prefer to
     use some form of alternative approach for sending data easily to
     the current session.  One simple approach is to alias some special
     character (such as '%') to 'tcp_command --'.

tcp_wait
     The sole argument is an integer or floating point number which
     gives the seconds to delay.  The shell will do nothing for that
     period except wait for input on all TCP sessions by calling
     tcp_read -a.  This is similar to the interactive behaviour at the
     command prompt when zle handlers are installed.

24.2.4 'One-shot' file transfer
-------------------------------

tcp_point PORT
tcp_shoot HOST PORT
     This pair of functions provide a simple way to transfer a file
     between two hosts within the shell.  Note, however, that bulk data
     transfer is currently done using cat.  tcp_point reads any data
     arriving at PORT and sends it to standard output; tcp_shoot
     connects to PORT on HOST and sends its standard input.  Any unused
     PORT may be used; the standard mechanism for picking a port is to
     think of a random four-digit number above 1024 until one works.

     To transfer a file from host woodcock to host springes, on
     springes:

          tcp_point 8091 >output_file

     and on woodcock:

          tcp_shoot springes 8091 <input_file

     As these two functions do not require tcp_open to set up a TCP
     connection first, they may need to be autoloaded separately.

24.3 TCP User-defined Functions
===============================

Certain functions, if defined by the user, will be called by the
function system in certain contexts.  This facility depends on the
module zsh/parameter, which is usually available in interactive shells
as the completion system depends on it.  None of the functions need be
defined; they simply provide convenient hooks when necessary.

Typically, these are called after the requested action has been taken,
so that the various parameters will reflect the new state.

tcp_on_alias ALIAS FD
     When an alias is defined, this function will be called with two
     arguments: the name of the alias, and the file descriptor of the
     corresponding session.

tcp_on_awol SESS FD
     If the function tcp_fd_handler is handling input from the line
     editor and detects that the file descriptor is no longer reusable,
     by default it removes it from the list of file descriptors handled
     by this method and prints a message.  If the function tcp_on_awol
     is defined it is called immediately before this point.  It may
     return status 100, which indicates that the normal handling should
     still be performed; any other return status indicates that no
     further action should be taken and the tcp_fd_handler should return
     immediately with the given status.  Typically the action of
     tcp_on_awol will be to close the session.

     The variable TCP_INVALIDATE_ZLE will be a non-empty string if it is
     necessary to invalidate the line editor display using 'zle -I'
     before printing output from the function.

     ('AWOL' is military jargon for 'absent without leave' or some
     variation.  It has no pre-existing technical meaning known to the
     author.)

tcp_on_close SESS FD
     This is called with the name of a session being closed and the file
     descriptor which corresponded to that session.  Both will be
     invalid by the time the function is called.

tcp_on_open SESS FD
     This is called after a new session has been defined with the
     session name and file descriptor as arguments.  If it returns a
     non-zero status, opening the session is assumed to fail and the
     session is closed again; however, tcp_open will continue to attempt
     to open any remaining sessions given on the command line.

tcp_on_rename OLDSESS FD NEWSESS
     This is called after a session has been renamed with the three
     arguments old session name, file descriptor, new session name.

tcp_on_spam SESS COMMAND ...
     This is called once for each session spammed, just _before_ a
     command is executed for a session by tcp_spam.  The arguments are
     the session name followed by the command list to be executed.  If
     tcp_spam was called with the option -t, the first command will be
     tcp_send.

     This function is called after $TCP_SESS is set to reflect the
     session to be spammed, but before any use of it is made.  Hence it
     is possible to alter the value of $TCP_SESS within this function.
     For example, the session arguments to tcp_spam could include extra
     information to be stripped off and processed in tcp_on_spam.

     If the function sets the parameter $REPLY to 'done', the command
     line is not executed; in addition, no prompt is printed for the -v
     option to tcp_spam.

tcp_on_unalias ALIAS FD
     This is called with the name of an alias and the corresponding
     session's file descriptor after an alias has been deleted.

24.4 TCP Utility Functions
==========================

The following functions are used by the TCP function system but will
rarely if ever need to be called directly.

tcp_fd_handler
     This is the function installed by tcp_open for handling input from
     within the line editor, if that is required.  It is in the format
     documented for the builtin 'zle -F' in *note Zle Builtins:: .

     While active, the function sets the parameter TCP_HANDLER_ACTIVE to
     1.  This allows shell code called internally (for example, by
     setting tcp_on_read) to tell if is being called when the shell is
     otherwise idle at the editor prompt.

tcp_output [ -q ] -P PROMPT -F FD -S SESS
     This function is used for both logging and handling output to
     standard output, from within tcp_read and (if $TCP_OUTPUT is set)
     tcp_send.

     The PROMPT to use is specified by -P; the default is the empty
     string.  It can contain:
     %c
          Expands to 1 if the session is the current session, otherwise
          0.  Used with ternary expressions such as '%(c.-.+)' to output
          '+' for the current session and '-' otherwise.

     %f
          Replaced by the session's file descriptor.

     %s
          Replaced by the session name.

     %%
          Replaced by a single '%'.

     The option -q suppresses output to standard output, but not to any
     log files which are configured.

     The -S and -F options are used to pass in the session name and file
     descriptor for possible replacement in the prompt.


File: zsh.info,  Node: TCP Parameters,  Next: TCP Examples,  Prev: TCP Functions,  Up: TCP Function System

24.5 TCP User Parameters
========================

Parameters follow the usual convention that uppercase is used for
scalars and integers, while lowercase is used for normal and associative
array.  It is always safe for user code to read these parameters.  Some
parameters may also be set; these are noted explicitly.  Others are
included in this group as they are set by the function system for the
user's benefit, i.e.  setting them is typically not useful but is
benign.

It is often also useful to make settable parameters local to a function.
For example, 'local TCP_SILENT=1' specifies that data read during the
function call will not be printed to standard output, regardless of the
setting outside the function.  Likewise, 'local TCP_SESS=SESS' sets a
session for the duration of a function, and 'local TCP_PROMPT='
specifies that no prompt is used for input during the function.

tcp_expect_lines
     Array.  The set of lines read during the last call to tcp_expect,
     including the last ($TCP_LINE).

tcp_filter
     Array.  May be set directly.  A set of extended globbing patterns
     which, if matched in tcp_output, will cause the line not to be
     printed to standard output.  The patterns should be defined as
     described for the arguments to tcp_expect.  Output of line to log
     files is not affected.

TCP_HANDLER_ACTIVE
     Scalar.  Set to 1 within tcp_fd_handler to indicate to functions
     called recursively that they have been called during an editor
     session.  Otherwise unset.

TCP_LINE
     The last line read by tcp_read, and hence also tcp_expect.

TCP_LINE_FD
     The file descriptor from which $TCP_LINE was read.
     ${tcp_by_fd[$TCP_LINE_FD]} will give the corresponding session
     name.

tcp_lines
     Array.  The set of lines read during the last call to tcp_read,
     including the last ($TCP_LINE).

TCP_LOG
     May be set directly, although it is also controlled by tcp_log.
     The name of a file to which output from all sessions will be sent.
     The output is proceeded by the usual $TCP_PROMPT.  If it is not an
     absolute path name, it will follow the user's current directory.

TCP_LOG_SESS
     May be set directly, although it is also controlled by tcp_log.
     The prefix for a set of files to which output from each session
     separately will be sent; the full filename is ${TCP_LOG_SESS}.SESS.
     Output to each file is raw; no prompt is added.  If it is not an
     absolute path name, it will follow the user's current directory.

tcp_no_spam_list
     Array.  May be set directly.  See tcp_spam for how this is used.

TCP_OUTPUT
     May be set directly.  If a non-empty string, any data sent to a
     session by tcp_send will be logged.  This parameter gives the
     prompt to be used in a file specified by $TCP_LOG but not in a file
     generated from $TCP_LOG_SESS.  The prompt string has the same
     format as TCP_PROMPT and the same rules for its use apply.

TCP_PROMPT
     May be set directly.  Used as the prefix for data read by tcp_read
     which is printed to standard output or to the log file given by
     $TCP_LOG, if any.  Any '%s', '%f' or '%%' occurring in the string
     will be replaced by the name of the session, the session's
     underlying file descriptor, or a single '%', respectively.  The
     expression '%c' expands to 1 if the session being read is the
     current session, else 0; this is most useful in ternary expressions
     such as '%(c.-.+)' which outputs '+' if the session is the current
     one, else '-'.

     If the prompt starts with %P, this is stripped and the complete
     result of the previous stage is passed through standard prompt
     %-style formatting before being output.

TCP_READ_DEBUG
     May be set directly.  If this has non-zero length, tcp_read will
     give some limited diagnostics about data being read.

TCP_SECONDS_START
     This value is created and initialised to zero by tcp_open.

     The functions tcp_read and tcp_expect use the shell's SECONDS
     parameter for their own timing purposes.  If that parameter is not
     of floating point type on entry to one of the functions, it will
     create a local parameter SECONDS which is floating point and set
     the parameter TCP_SECONDS_START to the previous value of $SECONDS.
     If the parameter is already floating point, it is used without a
     local copy being created and TCP_SECONDS_START is not set.  As the
     global value is zero, the shell elapsed time is guaranteed to be
     the sum of $SECONDS and $TCP_SECONDS_START.

     This can be avoided by setting SECONDS globally to a floating point
     value using 'typeset -F SECONDS'; then the TCP functions will never
     make a local copy and never set TCP_SECONDS_START to a non-zero
     value.

TCP_SESS
     May be set directly.  The current session; must refer to one of the
     sessions established by tcp_open.

TCP_SILENT
     May be set directly, although it is also controlled by tcp_log.  If
     of non-zero length, data read by tcp_read will not be written to
     standard output, though may still be written to a log file.

tcp_spam_list
     Array.  May be set directly.  See the description of the function
     tcp_spam for how this is used.

TCP_TALK_ESCAPE
     May be set directly.  See the description of the function tcp_talk
     for how this is used.

TCP_TIMEOUT
     May be set directly.  Currently this is only used by the function
     tcp_command, see above.

24.6 TCP User-defined Parameters
================================

The following parameters are not set by the function system, but have a
special effect if set by the user.

tcp_on_read
     This should be an associative array; if it is not, the behaviour is
     undefined.  Each key is the name of a shell function or other
     command, and the corresponding value is a shell pattern (using
     EXTENDED_GLOB).  Every line read from a TCP session directly or
     indirectly using tcp_read (which includes lines read by tcp_expect)
     is compared against the pattern.  If the line matches, the command
     given in the key is called with two arguments: the name of the
     session from which the line was read, and the line itself.

     If any function called to handle a line returns a non-zero status,
     the line is not output.  Thus a tcp_on_read handler containing only
     the instruction 'return 1' can be used to suppress output of
     particular lines (see, however, tcp_filter above).  However, the
     line is still stored in TCP_LINE and tcp_lines; this occurs after
     all tcp_on_read processing.

24.7 TCP Utility Parameters
===========================

These parameters are controlled by the function system; they may be read
directly, but should not usually be set by user code.

tcp_aliases
     Associative array.  The keys are the names of sessions established
     with tcp_open; each value is a space-separated list of aliases
     which refer to that session.

tcp_by_fd
     Associative array.  The keys are session file descriptors; each
     value is the name of that session.

tcp_by_name
     Associative array.  The keys are the names of sessions; each value
     is the file descriptor associated with that session.


File: zsh.info,  Node: TCP Examples,  Next: TCP Bugs,  Prev: TCP Parameters,  Up: TCP Function System

24.8 TCP Examples
=================

Here is a trivial example using a remote calculator.

To create a calculator server on port 7337 (see the dc manual page for
quite how infuriating the underlying command is):

     tcp_proxy 7337 dc

To connect to this from the same host with a session also named 'dc':

     tcp_open localhost 7337 dc

To send a command to the remote session and wait a short while for
output (assuming dc is the current session):

     tcp_command 2 4 + p

To close the session:

     tcp_close

The tcp_proxy needs to be killed to be stopped.  Note this will not
usually kill any connections which have already been accepted, and also
that the port is not immediately available for reuse.

The following chunk of code puts a list of sessions into an xterm
header, with the current session followed by a star.

     print -n "\033]2;TCP:" ${(k)tcp_by_name:/$TCP_SESS/$TCP_SESS\*} "\a"


File: zsh.info,  Node: TCP Bugs,  Prev: TCP Examples,  Up: TCP Function System

24.9 TCP Bugs
=============

The function tcp_read uses the shell's normal read builtin.  As this
reads a complete line at once, data arriving without a terminating
newline can cause the function to block indefinitely.

Though the function suite works well for interactive use and for data
arriving in small amounts, the performance when large amounts of data
are being exchanged is likely to be extremely poor.


File: zsh.info,  Node: Zftp Function System,  Next: User Contributions,  Prev: TCP Function System,  Up: Top

25 Zftp Function System
***********************

25.1 Description
================

This describes the set of shell functions supplied with the source
distribution as an interface to the zftp builtin command, allowing you
to perform FTP operations from the shell command line or within
functions or scripts.  The interface is similar to a traditional FTP
client (e.g.  the ftp command itself, see ftp(1)), but as it is entirely
done within the shell all the familiar completion, editing and globbing
features, and so on, are present, and macros are particularly simple to
write as they are just ordinary shell functions.

The prerequisite is that the zftp command, as described in *note The
zsh/zftp Module:: , must be available in the version of zsh installed at
your site.  If the shell is configured to load new commands at run time,
it probably is: typing 'zmodload zsh/zftp' will make sure (if that runs
silently, it has worked).  If this is not the case, it is possible zftp
was linked into the shell anyway: to test this, type 'which zftp' and if
zftp is available you will get the message 'zftp: shell built-in
command'.

Commands given directly with zftp builtin may be interspersed between
the functions in this suite; in a few cases, using zftp directly may
cause some of the status information stored in shell parameters to
become invalid.  Note in particular the description of the variables
$ZFTP_TMOUT, $ZFTP_PREFS and $ZFTP_VERBOSE for zftp.

* Menu:

* Installation::
* Zftp Functions::
* Miscellaneous Features::


File: zsh.info,  Node: Installation,  Next: Zftp Functions,  Up: Zftp Function System

25.2 Installation
=================

You should make sure all the functions from the Functions/Zftp directory
of the source distribution are available; they all begin with the two
letters 'zf'.  They may already have been installed on your system;
otherwise, you will need to find them and copy them.  The directory
should appear as one of the elements of the $fpath array (this should
already be the case if they were installed), and at least the function
zfinit should be autoloaded; it will autoload the rest.  Finally, to
initialize the use of the system you need to call the zfinit function.
The following code in your .zshrc will arrange for this; assume the
functions are stored in the directory ~/myfns:

     fpath=(~/myfns $fpath)
     autoload -U zfinit
     zfinit

Note that zfinit assumes you are using the zmodload method to load the
zftp command.  If it is already built into the shell, change zfinit to
zfinit -n.  It is helpful (though not essential) if the call to zfinit
appears after any code to initialize the new completion system, else
unnecessary compctl commands will be given.


File: zsh.info,  Node: Zftp Functions,  Next: Miscellaneous Features,  Prev: Installation,  Up: Zftp Function System

25.3 Functions
==============

The sequence of operations in performing a file transfer is essentially
the same as that in a standard FTP client.  Note that, due to a quirk of
the shell's getopts builtin, for those functions that handle options you
must use '--' rather than '-' to ensure the remaining arguments are
treated literally (a single '-' is treated as an argument).

25.3.1 Opening a connection
---------------------------

zfparams [ HOST [ USER [ PASSWORD ... ] ] ]
     Set or show the parameters for a future zfopen with no arguments.
     If no arguments are given, the current parameters are displayed
     (the password will be shown as a line of asterisks).  If a HOST is
     given, and either the USER or PASSWORD is not, they will be
     prompted for; also, any parameter given as '?' will be prompted
     for, and if the '?' is followed by a string, that will be used as
     the prompt.  As zfopen calls zfparams to store the parameters, this
     usually need not be called directly.

     A single argument '-' will delete the stored parameters.  This will
     also cause the memory of the last directory (and so on) on the
     other host to be deleted.

zfopen [ -1 ] [ HOST [ USER [ PASSWORD [ ACCOUNT ] ] ] ]
     If HOST is present, open a connection to that host under username
     USER with password PASSWORD (and, on the rare occasions when it is
     necessary, account ACCOUNT).  If a necessary parameter is missing
     or given as '?' it will be prompted for.  If HOST is not present,
     use a previously stored set of parameters.

     If the command was successful, and the terminal is compatible with
     xterm or is sun-cmd, a summary will appear in the title bar, giving
     the local host:directory and the remote host:directory; this is
     handled by the function zftp_chpwd, described below.

     Normally, the HOST, USER and PASSWORD are internally recorded for
     later re-opening, either by a zfopen with no arguments, or
     automatically (see below).  With the option '-1', no information is
     stored.  Also, if an open command with arguments failed, the
     parameters will not be retained (and any previous parameters will
     also be deleted).  A zfopen on its own, or a zfopen -1, never
     alters the stored parameters.

     Both zfopen and zfanon (but not zfparams) understand URLs of the
     form ftp://HOST/PATH... as meaning to connect to the HOST, then
     change directory to PATH (which must be a directory, not a file).
     The 'ftp://' can be omitted; the trailing '/' is enough to trigger
     recognition of the PATH.  Note prefixes other than 'ftp:' are not
     recognized, and that all characters after the first slash beyond
     HOST are significant in PATH.

zfanon [ -1 ] HOST
     Open a connection HOST for anonymous FTP. The username used is
     'anonymous'.  The password (which will be reported the first time)
     is generated as USER@HOST; this is then stored in the shell
     parameter $EMAIL_ADDR which can alternatively be set manually to a
     suitable string.

25.3.2 Directory management
---------------------------

zfcd [ DIR ]
zfcd -
zfcd OLD NEW
     Change the current directory on the remote server: this is
     implemented to have many of the features of the shell builtin cd.

     In the first form with DIR present, change to the directory DIR.
     The command 'zfcd ..' is treated specially, so is guaranteed to
     work on non-UNIX servers (note this is handled internally by zftp).
     If DIR is omitted, has the effect of 'zfcd ~'.

     The second form changes to the directory previously current.

     The third form attempts to change the current directory by
     replacing the first occurrence of the string OLD with the string
     NEW in the current directory.

     Note that in this command, and indeed anywhere a remote filename is
     expected, the string which on the local host corresponds to '~' is
     converted back to a '~' before being passed to the remote machine.
     This is convenient because of the way expansion is performed on the
     command line before zfcd receives a string.  For example, suppose
     the command is 'zfcd ~/foo'.  The shell will expand this to a full
     path such as 'zfcd /home/user2/pws/foo'.  At this stage, zfcd
     recognises the initial path as corresponding to '~' and will send
     the directory to the remote host as ~/foo, so that the '~' will be
     expanded by the server to the correct remote host directory.  Other
     named directories of the form '~name' are not treated in this
     fashion.

zfhere
     Change directory on the remote server to the one corresponding to
     the current local directory, with special handling of '~' as in
     zfcd.  For example, if the current local directory is ~/foo/bar,
     then zfhere performs the effect of 'zfcd ~/foo/bar'.

zfdir [ -rfd ] [ - ] [ DIR-OPTIONS ] [ DIR ]
     Produce a long directory listing.  The arguments DIR-OPTIONS and
     DIR are passed directly to the server and their effect is
     implementation dependent, but specifying a particular remote
     directory DIR is usually possible.  The output is passed through a
     pager given by the environment variable $PAGER, or 'more' if that
     is not set.

     The directory is usually cached for re-use.  In fact, two caches
     are maintained.  One is for use when there is no DIR-OPTIONS or
     DIR, i.e.  a full listing of the current remote directory; it is
     flushed when the current remote directory changes.  The other is
     kept for repeated use of zfdir with the same arguments; for
     example, repeated use of 'zfdir /pub/gnu' will only require the
     directory to be retrieved on the first call.  Alternatively, this
     cache can be re-viewed with the -r option.  As relative directories
     will confuse zfdir, the -f option can be used to force the cache to
     be flushed before the directory is listed.  The option -d will
     delete both caches without showing a directory listing; it will
     also delete the cache of file names in the current remote
     directory, if any.

zfls [ LS-OPTIONS ] [ DIR ]
     List files on the remote server.  With no arguments, this will
     produce a simple list of file names for the current remote
     directory.  Any arguments are passed directly to the server.  No
     pager and no caching is used.

25.3.3 Status commands
----------------------

zftype [ TYPE ]
     With no arguments, show the type of data to be transferred, usually
     ASCII or binary.  With an argument, change the type: the types 'A'
     or 'ASCII' for ASCII data and 'B' or 'BINARY', 'I' or 'IMAGE' for
     binary data are understood case-insensitively.

zfstat [ -v ]
     Show the status of the current or last connection, as well as the
     status of some of zftp's status variables.  With the -v option, a
     more verbose listing is produced by querying the server for its
     version of events, too.

25.3.4 Retrieving files
-----------------------

The commands for retrieving files all take at least two options.  -G
suppresses remote filename expansion which would otherwise be performed
(see below for a more detailed description of that).  -t attempts to set
the modification time of the local file to that of the remote file: see
the description of the function zfrtime below for more information.

zfget [ -Gtc ] FILE1 ...
     Retrieve all the listed files FILE1 ...  one at a time from the
     remote server.  If a file contains a '/', the full name is passed
     to the remote server, but the file is stored locally under the name
     given by the part after the final '/'.  The option -c (cat) forces
     all files to be sent as a single stream to standard output; in this
     case the -t option has no effect.

zfuget [ -Gvst ] FILE1 ...
     As zfget, but only retrieve files where the version on the remote
     server is newer (has a later modification time), or where the local
     file does not exist.  If the remote file is older but the files
     have different sizes, or if the sizes are the same but the remote
     file is newer, the user will usually be queried.  With the option
     -s, the command runs silently and will always retrieve the file in
     either of those two cases.  With the option -v, the command prints
     more information about the files while it is working out whether or
     not to transfer them.

zfcget [ -Gt ] FILE1 ...
     As zfget, but if any of the local files exists, and is shorter than
     the corresponding remote file, the command assumes that it is the
     result of a partially completed transfer and attempts to transfer
     the rest of the file.  This is useful on a poor connection which
     keeps failing.

     Note that this requires a commonly implemented, but non-standard,
     version of the FTP protocol, so is not guaranteed to work on all
     servers.

zfgcp [ -Gt ] REMOTE-FILE LOCAL-FILE
zfgcp [ -Gt ] RFILE1 ... LDIR
     This retrieves files from the remote server with arguments behaving
     similarly to the cp command.

     In the first form, copy REMOTE-FILE from the server to the local
     file LOCAL-FILE.

     In the second form, copy all the remote files RFILE1 ...  into the
     local directory LDIR retaining the same basenames.  This assumes
     UNIX directory semantics.

25.3.5 Sending files
--------------------

zfput [ -r ] FILE1 ...
     Send all the FILE1 ...  given separately to the remote server.  If
     a filename contains a '/', the full filename is used locally to
     find the file, but only the basename is used for the remote file
     name.

     With the option -r, if any of the FILES are directories they are
     sent recursively with all their subdirectories, including files
     beginning with '.'.  This requires that the remote machine
     understand UNIX file semantics, since '/' is used as a directory
     separator.

zfuput [ -vs ] FILE1 ...
     As zfput, but only send files which are newer than their remote
     equivalents, or if the remote file does not exist.  The logic is
     the same as for zfuget, but reversed between local and remote
     files.

zfcput FILE1 ...
     As zfput, but if any remote file already exists and is shorter than
     the local equivalent, assume it is the result of an incomplete
     transfer and send the rest of the file to append to the existing
     part.  As the FTP append command is part of the standard set, this
     is in principle more likely to work than zfcget.

zfpcp LOCAL-FILE REMOTE-FILE
zfpcp LFILE1 ... RDIR
     This sends files to the remote server with arguments behaving
     similarly to the cp command.

     With two arguments, copy LOCAL-FILE to the server as REMOTE-FILE.

     With more than two arguments, copy all the local files LFILE1 ...
     into the existing remote directory RDIR retaining the same
     basenames.  This assumes UNIX directory semantics.

     A problem arises if you attempt to use zfpcp LFILE1 RDIR, i.e.  the
     second form of copying but with two arguments, as the command has
     no simple way of knowing if RDIR corresponds to a directory or a
     filename.  It attempts to resolve this in various ways.  First, if
     the RDIR argument is '.' or '..' or ends in a slash, it is assumed
     to be a directory.  Secondly, if the operation of copying to a
     remote file in the first form failed, and the remote server sends
     back the expected failure code 553 and a reply including the string
     'Is a directory', then zfpcp will retry using the second form.

25.3.6 Closing the connection
-----------------------------

zfclose
     Close the connection.

25.3.7 Session management
-------------------------

zfsession [ -lvod ] [ SESSNAME ]
     Allows you to manage multiple FTP sessions at once.  By default,
     connections take place in a session called 'default'; by giving the
     command 'zfsession SESSNAME' you can change to a new or existing
     session with a name of your choice.  The new session remembers its
     own connection, as well as associated shell parameters, and also
     the host/user parameters set by zfparams.  Hence you can have
     different sessions set up to connect to different hosts, each
     remembering the appropriate host, user and password.

     With no arguments, zfsession prints the name of the current
     session; with the option -l it lists all sessions which currently
     exist, and with the option -v it gives a verbose list showing the
     host and directory for each session, where the current session is
     marked with an asterisk.  With -o, it will switch to the most
     recent previous session.

     With -d, the given session (or else the current one) is removed;
     everything to do with it is completely forgotten.  If it was the
     only session, a new session called 'default' is created and made
     current.  It is safest not to delete sessions while background
     commands using zftp are active.

zftransfer SESS1:FILE1 SESS2:FILE2
     Transfer files between two sessions; no local copy is made.  The
     file is read from the session SESS1 as FILE1 and written to session
     SESS2 as file FILE2; FILE1 and FILE2 may be relative to the current
     directories of the session.  Either SESS1 or SESS2 may be omitted
     (though the colon should be retained if there is a possibility of a
     colon appearing in the file name) and defaults to the current
     session; FILE2 may be omitted or may end with a slash, in which
     case the basename of FILE1 will be added.  The sessions SESS1 and
     SESS2 must be distinct.

     The operation is performed using pipes, so it is required that the
     connections still be valid in a subshell, which is not the case
     under versions of some operating systems, presumably due to a
     system bug.

25.3.8 Bookmarks
----------------

The two functions zfmark and zfgoto allow you to 'bookmark' the present
location (host, user and directory) of the current FTP connection for
later use.  The file to be used for storing and retrieving bookmarks is
given by the parameter $ZFTP_BMFILE; if not set when one of the two
functions is called, it will be set to the file .zfbkmarks in the
directory where your zsh startup files live (usually ~).

zfmark [ BOOKMARK ]
     If given an argument, mark the current host, user and directory
     under the name BOOKMARK for later use by zfgoto.  If there is no
     connection open, use the values for the last connection immediately
     before it was closed; it is an error if there was none.  Any
     existing bookmark under the same name will be silently replaced.

     If not given an argument, list the existing bookmarks and the
     points to which they refer in the form USER@HOST:DIRECTORY; this is
     the format in which they are stored, and the file may be edited
     directly.

zfgoto [ -n ] BOOKMARK
     Return to the location given by BOOKMARK, as previously set by
     zfmark.  If the location has user 'ftp' or 'anonymous', open the
     connection with zfanon, so that no password is required.  If the
     user and host parameters match those stored for the current
     session, if any, those will be used, and again no password is
     required.  Otherwise a password will be prompted for.

     With the option -n, the bookmark is taken to be a nickname stored
     by the ncftp program in its bookmark file, which is assumed to be
     ~/.ncftp/bookmarks.  The function works identically in other ways.
     Note that there is no mechanism for adding or modifying ncftp
     bookmarks from the zftp functions.

25.3.9 Other functions
----------------------

Mostly, these functions will not be called directly (apart from zfinit),
but are described here for completeness.  You may wish to alter
zftp_chpwd and zftp_progress, in particular.

zfinit [ -n ]
     As described above, this is used to initialize the zftp function
     system.  The -n option should be used if the zftp command is
     already built into the shell.

zfautocheck [ -dn ]
     This function is called to implement automatic reopening behaviour,
     as described in more detail below.  The options must appear in the
     first argument; -n prevents the command from changing to the old
     directory, while -d prevents it from setting the variable do_close,
     which it otherwise does as a flag for automatically closing the
     connection after a transfer.  The host and directory for the last
     session are stored in the variable $zflastsession, but the internal
     host/user/password parameters must also be correctly set.

zfcd_match PREFIX SUFFIX
     This performs matching for completion of remote directory names.
     If the remote server is UNIX, it will attempt to persuade the
     server to list the remote directory with subdirectories marked,
     which usually works but is not guaranteed.  On other hosts it
     simply calls zfget_match and hence completes all files, not just
     directories.  On some systems, directories may not even look like
     filenames.

zfget_match PREFIX SUFFIX
     This performs matching for completion of remote filenames.  It
     caches files for the current directory (only) in the shell
     parameter $zftp_fcache.  It is in the form to be called by the -K
     option of compctl, but also works when called from a widget-style
     completion function with PREFIX and SUFFIX set appropriately.

zfrglob VARNAME
     Perform remote globbing, as describes in more detail below.
     VARNAME is the name of a variable containing the pattern to be
     expanded; if there were any matches, the same variable will be set
     to the expanded set of filenames on return.

zfrtime LFILE RFILE [ TIME ]
     Set the local file LFILE to have the same modification time as the
     remote file RFILE, or the explicit time TIME in FTP format
     CCYYMMDDhhmmSS for the GMT timezone.  This uses the shell's
     zsh/datetime module to perform the conversion from GMT to local
     time.

zftp_chpwd
     This function is called every time a connection is opened, or
     closed, or the remote directory changes.  This version alters the
     title bar of an xterm-compatible or sun-cmd terminal emulator to
     reflect the local and remote hostnames and current directories.  It
     works best when combined with the function chpwd.  In particular, a
     function of the form

          chpwd() {
            if [[ -n $ZFTP_USER ]]; then
              zftp_chpwd
            else
              # usual chpwd e.g put host:directory in title bar
            fi
          }

     fits in well.

zftp_progress
     This function shows the status of the transfer.  It will not write
     anything unless the output is going to a terminal; however, if you
     transfer files in the background, you should turn off progress
     reports by hand using 'zstyle ':zftp:*' progress none'.  Note also
     that if you alter it, any output _must_ be to standard error, as
     standard output may be a file being received.  The form of the
     progress meter, or whether it is used at all, can be configured
     without altering the function, as described in the next section.

zffcache
     This is used to implement caching of files in the current directory
     for each session separately.  It is used by zfget_match and
     zfrglob.

