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zshmodules(1)

ZSHMODULES(1)               General Commands Manual              ZSHMODULES(1)

NAME
       zshmodules - zsh loadable modules

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

       The modules that are bundled with the zsh distribution are:

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

       zsh/cap
              Builtins  for manipulating POSIX.1e (POSIX.6) capability (privi‐
              lege) 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  evalua‐
              tions.

       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 con‐
              text.

       zsh/regex
              Interface to the POSIX regex library.

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

       zsh/net/socket
              Manipulation of Unix domain sockets

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

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

       zsh/net/tcp
              Manipulation of TCP sockets

       zsh/termcap
              Interface to the termcap database.

       zsh/terminfo
              Interface to the terminfo database.

       zsh/watch
              Reporting of login and logout events.

       zsh/zftp
              A builtin FTP client.

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

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

       zsh/zprof
              A module allowing profiling for shell functions.

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

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

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

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

       zgetattr [ -h ] filename attribute [ parameter ]
              Get the extended attribute attribute from  the  specified  file‐
              name. 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 file‐
              name.

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

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

THE ZSH/CAP MODULE
       The zsh/cap module is used for manipulating POSIX.1e (POSIX.6) capabil‐
       ity 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 ca‐
              pabilities, otherwise display the shell's current capabilities.

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

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

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

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

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

              The target of clone should be an unused terminal, such as an un‐
              used 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 al‐
              ready  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.

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 zshcom‐
       pctl(1).   The  other builtin command, compcall can be used in user-de‐
       fined completion widgets, see zshcompwid(1).

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

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

   Colored completion listings
       Whenever one of the parameters ZLS_COLORS or ZLS_COLOURS is set and the
       zsh/complist module is loaded or  linked  into  the  shell,  completion
       lists will be colored.  Note, however, that complist will not automati‐
       cally  be loaded if it is not linked in:  on systems with dynamic load‐
       ing, `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, sym‐
              bolic links are dereferenced and the target file used to  deter‐
              mine 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  file‐
              names 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 (`*') fol‐
       lowed 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 as‐
       terisk (file extensions).

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

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

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

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

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

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

   Scrolling in completion listings
       To enable scrolling through a completion list, the LISTPROMPT parameter
       must  be set.  Its value will be used as the prompt; if it is the empty
       string, a default prompt will be used.  The value may  contain  escapes
       of  the  form  `%x'.   It  supports the escapes `%B', `%b', `%S', `%s',
       `%U', `%u', `%F', `%f', `%K', `%k' and `%{...%}'  used  also  in  shell
       prompts  as well as three pairs of additional sequences: a `%l' or `%L'
       is replaced by the number of the last line shown and the  total  number
       of  lines  in  the form `number/total'; a `%m' or `%M' is replaced with
       the number of the last match shown and the total number of matches; and
       `%p' or `%P' is replaced with `Top', `Bottom' or the  position  of  the
       first line shown in percent of the total number of lines, respectively.
       In  each  of these cases the form with the uppercase letter will be re‐
       placed 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 list‐
       scroll 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 se‐
       lected.

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

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

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

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

       When  using the completion system based on shell functions, the MENUSE‐
       LECT 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 sup‐
       ports 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 se‐
       lect-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  com‐
       pletion  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  (be‐
       cause 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 move‐
       ment 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 al‐
              lowing 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 in‐
              serted 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 dis‐
              played;  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  `.ac‐
       cept-line'  has  the effect of leaving menu selection and accepting the
       entire command line.

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

              bindkey -M menuselect '^M' send-break

       after loading the zsh/complist module.

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

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

       compdescribe
              This is used by the _describe function to build the displays for
              the matches and to get the strings to add as matches with  their
              options.   On  the first call one of the options -i or -I should
              be supplied as the first argument.  In the first  case,  display
              strings  without the descriptions will be generated, in the sec‐
              ond case, the string used to separate the matches from their de‐
              scriptions must be given as the second argument and the descrip‐
              tions (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 reg‐
              ister 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  di‐
              rectory  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 re‐
              moving 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 quot‐
              ing  themselves.  Instead of interpreting the first character of
              the all_quotes key of the compstate special association and  us‐
              ing  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  oth‐
              erwise.

       comptags
       comptry
              These implement the internals of the tags mechanism.

       compvalues
              Like comparguments, but for the _values function.

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

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

              The  subcommand  addwin  creates  a window with nlines lines and
              ncols columns.  Its upper left corner will be placed at row  be‐
              gin_y  and  column begin_x of the screen.  targetwin is a string
              and refers to the name of a window that  is  not  currently  as‐
              signed.   Note in particular the curses convention that vertical
              values appear 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 sub‐
              windows are relative to the screen,  not  the  parent,  as  with
              other windows.

              Use  the  subcommand  delwin to delete a window created with ad‐
              dwin.  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.  re‐
              fresh 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 posi‐
              tion 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  fore‐
              ground/background  color  pair for any successive character out‐
              put.  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,  stand‐
              out, 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 de‐
              fault/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 char‐
              acters 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  pa‐
              rameter REPLY.

              If  both param and kparam are supplied, the key is read in `key‐
              pad' 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 descrip‐
              tion 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 in‐
              put.  This is only available with  the  ncurses  library;  mouse
              handling  can  be  detected  by  checking for the exit status of
              `zcurses mouse' with no arguments.  If a mouse button is clicked
              (or double- or triple-clicked, or pressed  or  released  with  a
              configurable delay from being clicked) then kparam is set to the
              string  MOUSE,  and  mparam is set to an array consisting of the
              following elements:
              -      An identifier to discriminate  different  input  devices;
                     this is only rarely useful.
              -      The x, y and z coordinates of the mouse click relative to
                     the  full  screen,  as three elements in that order (i.e.
                     the y coordinate is, unusually, after the x  coordinate).
                     The  z coordinate is only available for a few unusual in‐
                     put devices and is otherwise set to zero.
              -      Any events that occurred as separate items; usually there
                     will be just one.  An  event  consists  of  PRESSED,  RE‐
                     LEASED,  CLICKED,  DOUBLE_CLICKED  or TRIPLE_CLICKED fol‐
                     lowed 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 win‐
              dow; most terminal emulators  handle  some  mouse  events  them‐
              selves.   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 han‐
              dling is possible, else status 1.  Otherwise, the possible argu‐
              ments  (which  may  be combined on the same command line) are as
              follows.  delay num sets the maximum delay in  milliseconds  be‐
              tween  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.  How‐
              ever, it appears reports for mouse motion are not currently  im‐
              plemented.

              The  subcommand timeout specifies a timeout value for input from
              targetwin.  If intval is negative, `zcurses input' waits indefi‐
              nitely 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, re‐
              size_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. Mul‐
              tiple 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 versatil‐
              ity and should normally be not needed.

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

       ZCURSES_COLOR_PAIRS
              Readonly  integer.   The   maximum   number   of   color   pairs
              fg_col/bg_col  that  may  be defined in `zcurses attr' commands;
              note this limit applies to all color pairs that have  been  used
              whether  or  not  they are currently active.  This value is ini‐
              tialised 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; avail‐
              able as soon as the module is loaded.

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

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

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

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

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

              -n     Suppress printing a newline after the formatted string.

              -q     Run quietly; suppress printing of all error messages  de‐
                     scribed  below.   Errors for invalid epochtime values are
                     always printed.

              -r     With the option -r (reverse), use format to parse the in‐
                     put 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 strp‐
                     time(3).  This means that zsh format extensions  are  not
                     available, but for reverse lookup they are not required.

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

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

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

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

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

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

       EPOCHREALTIME
              A  floating point value representing the number of seconds since
              the epoch.  The notional  accuracy  is  to  nanoseconds  if  the
              clock_gettime  call  is available and to microseconds otherwise,
              but in practice the range of double precision floating point and
              shell scheduling latencies may be significant effects.

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

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

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

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

       The builtins in this module are:

       ztie -d db/gdbm -f filename [ -r ] arrayname
              Open the GDBM database identified by filename and,  if  success‐
              ful,  create the associative array arrayname linked to the file.
              To create a local tied array, the parameter must  first  be  de‐
              clared,  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 parame‐
              ters made readonly with `ztie -r'.

              This happens automatically if the parameter is explicitly  unset
              or  its local scope (function) ends.  Note that a readonly para‐
              meter 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 data‐
       base on each reference.  Thus, for example, the values  in  a  readonly
       array may be changed by a second writer of the same database file.

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

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

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

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

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

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

THE ZSH/FILES MODULE
       The zsh/files module makes available some common commands for file  ma‐
       nipulation 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  directo‐
              ries,  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 en‐
              ables 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 acciden‐
              tally 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  separa‐
              tor.

              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  directo‐
              ries, 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 en‐
              ables  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  acci‐
              dentally  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 directo‐
              ries.  This check can be overridden using the -d option.   Typi‐
              cally  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  compati‐
              bility;  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 di‐
              rectory  then  it will be removed, instead of followed.  If this
              option is used with multiple filenames and the target is a  sym‐
              bolic 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 spec‐
              ified 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.   Histori‐
              cal  versions  of  mv,  when actual renaming is impossible, fall
              back on copying and removing files; if  this  behaviour  is  de‐
              sired, use cp and rm manually.  This may change in a future ver‐
              sion.

       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  directo‐
              ries  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 in‐
              dications.  -f takes precedence.

              The -R and -r options cause rm to recursively descend  into  di‐
              rectories,  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  en‐
              ables  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  di‐
              rectories being moved up the tree.

       rmdir dir ...
              Removes empty directories specified.

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

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

       langinfo
              An  associative  array that maps langinfo elements to their val‐
              ues.

              Your implementation may support a number of the following keys:

              CODESET, D_T_FMT, D_FMT, T_FMT, RADIXCHAR, THOUSEP, YESEXPR, NO‐
              EXPR,   CRNCYSTR,   ABDAY_{1..7},   DAY_{1..7},   ABMON_{1..12},
              MON_{1..12},   T_FMT_AMPM,   AM_STR,   PM_STR,  ERA,  ERA_D_FMT,
              ERA_D_T_FMT, ERA_T_FMT, ALT_DIGITS

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

       mapfile
              This associative array takes as keys the names of files; the re‐
              sulting 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  ques‐
              tion  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, edit‐
              ing 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=("${(f@)mapfile[filename]}")'.  The
              double  quotes  and the `@' are necessary to prevent empty lines
              from being removed.  Note that if the file ends with a  newline,
              the  shell  will split on the final newline, generating an addi‐
              tional empty  field;  this  can  be  suppressed  by  using  `ar‐
              ray=("${(f@)${mapfile[filename]%$'\n'}}")'.

   Limitations
       Although  reading  and  writing  of the file in question is efficiently
       handled, zsh's internal memory management may be  arbitrarily  baroque;
       however,  mapfile is usually very much more efficient than anything in‐
       volving a loop.  Note in particular that the whole contents of the file
       will always reside physically in memory when accessed (possibly  multi‐
       ple times, due to standard parameter substitution operations).  In par‐
       ticular,  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 un‐
       writable files, as the parameter mechanism is too low in the shell exe‐
       cution hierarchy to make this convenient.

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

THE ZSH/MATHFUNC MODULE
       The zsh/mathfunc module provides standard  mathematical  functions  for
       use when evaluating mathematical formulae.  The syntax agrees with nor‐
       mal 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  func‐
       tions  behave as noted in the manual page for the corresponding C func‐
       tion, except that any arguments out of range for the function in  ques‐
       tion 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 op‐
       tionally take a second argument, in which case it behaves  like  the  C
       function atan2.  The ilogb function takes a single floating point argu‐
       ment, 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  expres‐
       sions.

       The  functions  min, max, and sum are defined not in this module but in
       the zmathfunc autoloadable function, described in the  section  `Mathe‐
       matical Functions' in zshcontrib(1).

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

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

       The  following take a floating point first argument and an integer sec‐
       ond 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 in‐
       teger.  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  ran‐
       dom 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 in‐
       dependent, 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,  how‐
       ever,  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 re‐
       turns to the same sequence of random numbers used in  the  first  call,
       unaffected by the intervening rand48().

THE ZSH/NEARCOLOR MODULE
       The  zsh/nearcolor  module  replaces  colours specified as hex triplets
       with the nearest colour in the 88  or  256  colour  palettes  that  are
       widely  used by terminal emulators.  By default, 24-bit true colour es‐
       cape 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 pre‐
       dictable 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 load‐
       ing the zsh/nearcolor module. For example,  the  following  checks  the
       COLORTERM environment variable:

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

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

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

       On  loading,  the  module  tests  if any of the start-up files .zshenv,
       .zprofile, .zshrc or .zlogin exist in the directory given by the  envi‐
       ronment  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  direc‐
       tory of the site-functions directory, and if that is not found the mod‐
       ule searches in a version-specific directory, usually the parent of the
       functions  directory containing version-specific functions.  (These di‐
       rectories  can  be  configured  when  zsh  is  built  using  the  --en‐
       able-site-scriptdir=dir  and --enable-scriptdir=dir flags to configure,
       respectively;   the   defaults   are    prefix/share/zsh    and    pre‐
       fix/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 exe‐
       cuted.

       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 administra‐
       tors.

       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  func‐
       tion  is  documented  in  the section `User Configuration Functions' in
       zshcontrib(1).

THE ZSH/PARAMETER MODULE
       The zsh/parameter module gives access to some of the internal hash  ta‐
       bles 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 un‐
              set.  Setting a key to one of these strings is like  setting  or
              unsetting  the option, respectively. Unsetting a key in this ar‐
              ray 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  in‐
              voked.  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  re‐
              solved,  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 com‐
              mands currently enabled. The keys are the names of  the  builtin
              commands  and the values are either `undefined' for builtin com‐
              mands 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 parame‐
              ters currently defined. The values are  strings  describing  the
              type  of the parameter, in the same format used by the t parame‐
              ter flag, see zshexpn(1) .  Setting or unsetting  keys  in  this
              array is not possible.

       modules
              An  associative array giving information about modules. The keys
              are the names of  the  modules  loaded,  registered  to  be  au‐
              toloaded,  or aliased. The value says which state the named mod‐
              ule 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 ar‐
              ray, 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  direc‐
              tory of the job).

              The  keys  of  the associative arrays are usually valid job num‐
              bers, 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 com‐
              mand 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  val‐
              ues  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 cur‐
              rent job, `-' for the previous job and empty otherwise. This  is
              followed  by  one `:pid=state' for every process in the job. The
              pids are, of course, the process IDs and the state describes the
              state of that process.

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

              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  com‐
              mand.

       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 file‐
              name: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 re‐
              solved.

              Most  users  will  be interested in the information in the func‐
              filetrace array instead.

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

              The  standard shell array zsh_eval_context can be used to deter‐
              mine the type of shell construct being executed at  each  depth:
              note,  however, that is in the opposite order, with the most re‐
              cent 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 $func‐
              stack.

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

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

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

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

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

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

              Upon successful match, if  the  expression  captures  substrings
              within parentheses, pcre_match will set the array match to those
              substrings, unless the -a option is given, in which case it will
              set the array arr.  Similarly, the variable MATCH will be set to
              the  entire  matched portion of the string, unless the -v option
              is given, in which case the variable var will be set.  No  vari‐
              ables  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 nec‐
              essarily the same as the character position when  UTF-8  charac‐
              ters  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, in‐
              stead use the -i switch of pcre_compile.

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

       This module provides a single autoloaded builtin:

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

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

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

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

       As with other typeset equivalents, private is both a builtin and a  re‐
       served  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 pri‐
       vate.  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 be‐
              haves as a local, except as noted above for tied or special  pa‐
              rameters.

       •      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 vis‐
              ible and may be assigned  or  unset.   This  includes  calls  to
              anonymous  functions,  although  that may also change in the fu‐
              ture.  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.  Gener‐
              ally, exporting private parameters should be avoided.

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

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

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

              For example,

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

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

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

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

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

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

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

       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  indi‐
              cates  the time since the epoch (1970/01/01 00:00); this is use‐
              ful in combination with the features in the zsh/datetime module,
              see the zsh/datetime module entry in zshmodules(1).

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

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

              Commands are executed either immediately  before  a  prompt,  or
              while the shell's line editor is waiting for input.  In the lat‐
              ter 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 emula‐
              tor'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 edi‐
              tor 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  num‐
              bers  shown  when  sched is run with no arguments (provided that
              the KSH_ARRAYS option is not set).  The value of the array  con‐
              sists  of the scheduled time in seconds since the epoch (see the
              section `The zsh/datetime Module' for facilities for using  this
              number), followed by a colon, followed by any options (which may
              be empty but will be preceded by a `-' otherwise), followed by a
              colon, followed by the command to be executed.

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

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

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

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

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

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

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

                     exec {REPLY}>&-

   Inbound Connections
       zsocket -l [ -v ] [ -d fd ] filename
              zsocket  -l will open a socket listening on filename.  The shell
              parameter REPLY will be set to the  file  descriptor  associated
              with  that  listener.   The file descriptor remains open in sub‐
              shells 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 as‐
              sociated 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  exter‐
              nal 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  connec‐
              tion is pending.  Otherwise it will wait for one.

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

THE ZSH/STAT MODULE
       The  zsh/stat module makes available one builtin command under two pos‐
       sible 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 dis‐
                     play 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  op‐
                     tion, 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  pre‐
              ceded  by a `+' in the option list; only one element is allowed.
              The element may be shortened to any unique set of leading  char‐
              acters.  Otherwise, all elements will be shown for all files.

              Options:

              -A array
                     Instead of displaying the results on standard output, as‐
                     sign  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, respec‐
                     tively.  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 preced‐
                     ing all the others.  Other  formatting  options  are  re‐
                     spected.

              -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 for‐
                     matting of the time elements.  The format string supports
                     all of the zsh extensions described in the section EXPAN‐
                     SION OF PROMPT SEQUENCES in zshmisc(1).   In  particular,
                     -F  %s.%N  can be used to show timestamps with nanosecond
                     precision if supported by the system.  The -s  option  is
                     implied.

              -g     Show  the time elements in the GMT time zone.  The -s op‐
                     tion is implied.

              -l     List the names of the type elements (to  standard  output
                     or an array as appropriate) and return immediately; argu‐
                     ments, 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  re‐
                     turned.  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 se‐
                     lected.

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

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

   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 er‐
              ror 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 ap‐
              pending, respectively. The -m option allows the initial  permis‐
              sions 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  vari‐
              able  name can be given to which the file descriptor number will
              be assigned.

              The -o option allows various system specific options to be spec‐
              ified as a comma-separated list. The following is a list of pos‐
              sible 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 num‐
              ber 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 writ‐
                     ing 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 at‐
                     tempted.

       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  de‐
              scriptor  outfd, or 1 if that is not given, using the write sys‐
              tem 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  out‐
              put,  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 ER‐
              RNO 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 con‐
              venient 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  de‐
              scriptor  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 lock‐
              ing.

              By default the shell waits indefinitely for the lock to succeed.
              The option -t timeout specifies a timeout for the lock  in  sec‐
              onds;  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; oth‐
              erwise it is closed at that point and the lock released.

              If the option -r is given, the lock is only for reading,  other‐
              wise  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  re‐
              turned.  Status 1 can indicate one of two things:  subcommand is
              known but not supported by the current operating system, or sub‐
              command  is not known (possibly because this is an older version
              of the shell before it was implemented).

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

   Parameters
       errnos A  readonly  array of the names of errors defined on the system.
              These are typically macros defined in C by including the  system
              header  file  errno.h.  The index of each name (assuming the op‐
              tion KSH_ARRAYS is unset) corresponds to the error number.   Er‐
              ror  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  cur‐
                     rent  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  >(...)  expan‐
                     sions.

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 com‐
              mand 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  con‐
              tents  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  nor‐
                     mal  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 ad‐
                     dress 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  ad‐
                     dress for a session opened for listening.

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

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

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

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

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

              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  associ‐
              ated with listenfd.  The connection will be added to the session
              table  and the shell parameter REPLY will be set to the file de‐
              scriptor associated with the inbound connection.

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

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

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

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

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

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

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

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

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

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

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

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

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

       The zsh/termcap module makes available one parameter:

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

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

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

       The zsh/terminfo module makes available one parameter:

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

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

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

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

              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  as‐
              signment  to  watch so that it does not immediately perform file
              generation); the setting of  the  EXTENDED_GLOB  option  is  re‐
              spected.   Any  or  all of these components may be present in an
              entry; if a login/logout event matches all of them,  it  is  re‐
              ported.

              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 follow‐
              ing 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.  Other‐
                     wise they are treated as ordinary strings.

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

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

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

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

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

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

              %T     The time, in 24-hour format.

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

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

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

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

              %(x:true-text:false-text)
                     Specifies a ternary expression.  The character  following
                     the  x  is arbitrary; the same character is used to sepa‐
                     rate the text for the "true" result  from  that  for  the
                     "false"  result.  Both the separator and the right paren‐
                     thesis may be escaped with a backslash.  Ternary  expres‐
                     sions 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.  Ei‐
                     ther or both of the branches may be empty, but both sepa‐
                     rators 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 cur‐
              rent setting of the watch parameter.

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

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

              All  commands  consist  of the command name zftp followed by the
              name of a subcommand.  These are listed below.  The return  sta‐
              tus  of  each  subcommand  is supposed to reflect the success or
              failure of the remote operation.  See a description of the vari‐
              able ZFTP_VERBOSE for more information on how responses from the
              server may be printed.

   Subcommands
       open host[:port] [ user [ password [ account ] ] ]
              Open a new FTP session to host, which  may  be  the  name  of  a
              TCP/IP  connected host or an IP number in the standard dot nota‐
              tion.  If the argument is in the form host:port, open a  connec‐
              tion 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 descrip‐
              tion 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 au‐
              tomatically  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 `Vari‐
              ables' 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 er‐
              ror 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 ar‐
              guments.  Only those given on the command line  will  be  remem‐
              bered.   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 neces‐
              sary 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 liter‐
              ally, 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 sys‐
              tems.

       dir [ arg ... ]
              Give  a (verbose) listing of the remote directory.  The args are
              passed directly to the server. The command's behaviour is imple‐
              mentation 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 out‐
              put.

       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 for‐
              mat CCYYMMDDhhmmSS consisting of year, month, date,  hour,  min‐
              utes  and  seconds in GMT.  Note that this format, including the
              length, is guaranteed, so that time strings can be directly com‐
              pared 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 infor‐
              mation.  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  argu‐
              ments,  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 send‐
              ing 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  append‐
              ing  to an incomplete local file.  However, note that this abil‐
              ity 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 para‐
              meters 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  ar‐
              gument,  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 exist‐
              ing  session becomes the new current session, otherwise the cur‐
              rent session is not changed.  If the session  being  deleted  is
              the  only one, a new session called `default' is created and be‐
              comes 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  com‐
              mands which use zftp are still active.

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

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

       ZFTP_IP
              Readonly.  The IP address of the current connection in dot nota‐
              tion.

       ZFTP_HOST
              Readonly.   The  hostname  of the current remote server.  If the
              host was opened as an IP number,  ZFTP_HOST  contains  that  in‐
              stead;  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  con‐
              nection  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  appro‐
              priate 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  re‐
              sponse  to  an FTP SYST request.  The most interesting case is a
              string beginning "UNIX Type: L8", which ensures maximum compati‐
              bility 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 descrip‐
              tion of the session subcommand.

       ZFTP_PREFS
              A  string  of  preferences for altering aspects of zftp's behav‐
              iour.  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  be‐
                     ing  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 cor‐
              respond 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 in‐
              terpretation of the word `transient'.

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

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

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

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

              When it is called with a transfer in progress, the following ad‐
              ditional 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 re‐
                     trieved, 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  al‐
                     ways available.

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

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

   Problems
       A  connection may not be opened in the left hand side of a pipe as this
       occurs in a subshell and the file information is  not  updated  in  the
       main shell.  In the case of type or mode changes or closing the connec‐
       tion  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 other‐
       wise 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 order‐
       ing of that information.

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

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

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

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

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

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

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

              At  the  top  there is a summary listing all functions that were
              called at least once.  This summary is sorted in decreasing  or‐
              der  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  in‐
              dented  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 invoca‐
              tions 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 in‐
              ternal counters and will not show the listing.

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

       zpty [ -e ] [ -b ] name [ arg ... ]
              The arguments following name are concatenated  with  spaces  be‐
              tween,  then  executed  as  a  command, as if passed to the eval
              builtin.  The command runs under a newly assigned  pseudo-termi‐
              nal; 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 ter‐
              minal to be monitored with ZLE  descriptor  handlers  (see  zsh‐
              zle(1))  or  manipulated  with  sysread  and  syswrite  (see THE
              ZSH/SYSTEM MODULE in zshmodules(1)).  Warning:  Use  of  sysread
              and  syswrite is not recommended; use zpty -r and zpty -w unless
              you know exactly what you are doing.

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

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

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

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

       zpty -r [ -mt ] name [ param [ pattern ] ]
              The  -r  option  can  be  used to read the output of the command
              name.  With only a name argument, the output read is  copied  to
              the  standard  output.  Unless the pseudo-terminal is non-block‐
              ing, copying continues until the command under the pseudo-termi‐
              nal exits; when non-blocking, only as much output as is  immedi‐
              ately  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 sta‐
              tus 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  pat‐
              tern,  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 com‐
              mands currently defined.  If the -L option  is  given,  this  is
              done in the form of calls to the zpty builtin.

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

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

              Arguments and options may be intermingled in any order.  Non-op‐
              tion arguments are file descriptors, which must be decimal inte‐
              gers.  By default, file descriptors are to be tested  for  read‐
              ing,  i.e. zselect will return when data is available to be read
              from the file descriptor, or more precisely, when a read  opera‐
              tion  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 in‐
              dicate 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 zse‐
              lect.  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 re‐
              quested operations.

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

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

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

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

              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 char‐
              acters 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  (be‐
              cause 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, metapat‐
                     tern, 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  ":comple‐
                     tion:*"' will match any supplied pattern beginning `:com‐
                     pletion:',   not  just  ":completion:*":   use  ':comple‐
                     tion:\*' to match that.   The  optional  second  argument
                     limits  the  output  to a specific style (not a pattern).
                     -L is not compatible with any other 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  re‐
                     sulting  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  evalua‐
                     tion.   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 defini‐
                     tions 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 in‐
                     terpreted 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 de‐
                     clared 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  re‐
                     turns  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 ap‐
              pearance of the sequence `%char' in format to be replaced by the
              string.  The `%' sequence may also contain optional minimum  and
              maximum  field  width  specifications  between  the  `%' and the
              `char' in the form `%min.maxc', i.e. the minimum field width  is
              given first and if the maximum field width is used, it has to be
              preceded  by  a dot.  Specifying a minimum field width makes the
              result be padded with spaces to  the  right  if  the  string  is
              shorter  than  the  requested width.  Padding to the left can be
              achieved by giving a negative minimum field width.  If a maximum
              field width is specified, the string  will  be  truncated  after
              that  many  characters.   After  all `%' sequences for the given
              specs have been processed, the resulting string is stored in the
              parameter param.

              The %-escapes also understand ternary expressions  in  the  form
              used  by  prompts.  The % is followed by a `(' and then an ordi‐
              nary 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 for‐
              mat specifier, which is followed by a piece of `true' text,  the
              delimiter  character again, a piece of `false' text, and a clos‐
              ing parenthesis.  The complete expression (without  the  digits)
              thus  looks like `%(X.text1.text2)', except that the `.' charac‐
              ter is arbitrary.  The value given for the format  specifier  in
              the  char:string  expressions is evaluated as a mathematical ex‐
              pression, 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 speci‐
              fier is present and non-empty.  A test number indicates a  mini‐
              mum  width for the value given in the format specifier. Negative
              numbers reverse this, so the test is for whether the  value  ex‐
              ceeds 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  with‐
              out  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 pa‐
              rameters,  i.e. the set of arguments given by $*.  Each spec de‐
              scribes 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 ar‐
              ray, 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 exam‐
                     ple, 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  argu‐
                     ment,  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 argu‐
                     ment;  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 para‐
              meter, unless it begins with a `-'.  There is  no  special  han‐
              dling  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  -foo‐
              bar' (for example) is unambiguous. However, due to the aforemen‐
              tioned  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 vali‐
                     dation 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 regard‐
                     less 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 ar‐
                     ray is replaced when any of the specs is used.   Individ‐
                     ual  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  val‐
                     ues  are stored, not the way $* is parsed, so results may
                     be unpredictable if the `name+' specifier is used  incon‐
                     sistently.

              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 posi‐
              tional 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)



ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:

       box; cbp-1 | cbp-1 l | l .  ATTRIBUTE TYPE ATTRIBUTE VALUE = Availabil‐
       ity   shell/zsh = Stability Volatile

NOTES
       Source code for open source software components in Oracle  Solaris  can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.

       This software was built from source available at:
       https://github.com/oracle/solaris-userland

       The original community source was downloaded from:
       https://downloads.sourceforge.net/project/zsh/zsh/5.9/zsh-5.9.tar.xz

       Further information about this software can be found on the open source
       community website at https://www.zsh.org/.

zsh 5.9                          May 14, 2022                    ZSHMODULES(1)
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