Provided by: zsh_4.3.4-24ubuntu1_i386 bug

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.  The modules that  are  bundled
       with the zsh distribution are:

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

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

       zsh/compctl
              The compctl builtin for controlling completion.

       zsh/complete
              The basic completion code.

       zsh/complist
              Completion listing extensions.

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

       zsh/datetime
              Some date/time commands and parameters.

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

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

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

       zsh/net/socket
              Manipulation of Unix domain sockets

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

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

       zsh/net/tcp
              Manipulation of TCP sockets

       zsh/termcap
              Interface to the termcap database.

       zsh/terminfo
              Interface to the terminfo database.

       zsh/zftp
              A builtin FTP client.

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

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

       zsh/zprof
              A module allowing profiling for shell functions.

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

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

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

THE ZSH/CAP MODULE

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

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

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

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

THE ZSH/CLONE MODULE

       The zsh/clone module makes available one builtin command:

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

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

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

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

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

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

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

THE ZSH/COMPCTL MODULE

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

THE ZSH/COMPLETE MODULE

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

THE ZSH/COMPLIST MODULE

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

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

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

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

       fi 0   for regular files

       di 32  for directories

       ln 36  for symbolic links

       pi 31  for named pipes (FIFOs)

       so 33  for sockets

       bd 44;37
              for block devices

       cd 44;37
              for character devices

       ex 35  for executable files

       mi none
              for a non-existent file (default is the value defined for fi)

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

       rc m   for the right code

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

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

       ec none
              for the end code

       Apart  from  these  strings,  the  name  may  also be an asterisk (‘*’)
       followed by any string. The value given for such a string will be  used
       for all files whose name ends with the string.  The name may also be an
       equals sign (‘=’) followed by a pattern.   The  value  given  for  this
       pattern will be used for all matches (not just filenames) whose display
       string are matched by the pattern.  Definitions for both of these  take
       precedence over the values defined for file types and the form with the
       leading asterisk takes precedence over the form with the leading  equal
       sign.

       The  last  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.

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

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

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

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

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

       send-break
              stops listing discarding the key pressed

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

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

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

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

   Menu selection
       The  zsh/complist  module also offers an alternative style of selecting
       matches from a list, called menu selection, which can be  used  if  the
       shell is set up to return to the last prompt after showing a completion
       list (see the ALWAYS_LAST_PROMPT option in zshoptions(1)).  It  can  be
       invoked  directly  by  the  widget  menu-select  defined by the module.
       Alternatively, the parameter MENUSELECT can be set to an integer, which
       gives  the  minimum  number of matches that must be present before menu
       selection is automatically turned on.  This second method requires that
       menu  completion  be  started,  either  directly  from a widget such as
       menu-complete, or due to one of the options MENU_COMPLETE or  AUTO_MENU
       being  set.  If MENUSELECT is set, but is 0, 1 or empty, menu selection
       will always be started during an ambiguous menu completion.

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

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

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

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

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

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

       Selecting  matches  is  done  by  moving  the mark around using the zle
       movement functions.  When not all matches can be shown on the screen at
       the  same  time, the list will scroll up and down when crossing the top
       or bottom line.  The  following  zle  functions  have  special  meaning
       during menu selection:

       accept-line
              accepts the current match and leaves menu selection

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       vi-insert
              this toggles between normal and interactive mode; in interactive
              mode the keys bound to self-insert and self-insert-unmeta insert
              into  the  command  line  as  in normal editing mode but without
              leaving menu selection; after each character completion is tried
              again  and the list changes to contain only the new matches; the
              completion  widgets  make  the  longest  unambiguous  string  be
              inserted  in  the command line and undo and backward-delete-char
              go back to the previous set of matches

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

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

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

              bindkey -M menuselect^Msend-break

       after loading the zsh/complist module.

THE ZSH/COMPUTIL MODULE

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

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

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

              Once  compdescribe  has been called with either the -i or the -I
              option, it can be repeatedly called with the -g option  and  the
              names  of  five arrays as its arguments.  This will step through
              the different sets of matches and store the options in the first
              array,  the strings with descriptions in the second, the matches
              for these in the third, the strings without descriptions in  the
              fourth,  and the matches for them in the fifth array.  These are
              then directly given to compadd to register the matches with  the
              completion code.

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

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

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

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

       comptags
       comptry
              These implement the internals of the tags mechanism.

       compvalues
              Like comparguments, but for the _values function.

THE ZSH/DATETIME MODULE

       The zsh/datetime module makes available one builtin command:

       strftime [ -s scalar ] format epochtime
       strftime -r [ -q ] [ -s scalar ] format timestring
              Output the date denoted by epochtime in the format specified.

              With the option -r (reverse), use the format format to parse the
              input  string  timestring and output the number of seconds since
              the epoch at which the time occurred.  If no timezone is parsed,
              the  current  timezone is used; other parameters are set to zero
              if not present.  If timestring does not match format the command
              returns  status  1;  it will additionally print an error message
              unless the option -q (quiet) is given.   If  timestring  matches
              format  but  not  all  characters  in  timestring were used, the
              conversion succeeds; however, a warning  is  issued  unless  the
              option  -q  is given.  The matching is implemented by the system
              function strptime; see strptime(3).  This means that zsh  format
              extensions  are  not  available, however for reverse lookup they
              are not required.  If  the  function  is  not  implemented,  the
              command  returns  status  2  and  (unless  -q is given) prints a
              message.

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

       The zsh/datetime module makes available one parameter:

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

THE ZSH/DELTOCHAR MODULE

       The zsh/deltochar module makes available two ZLE functions:

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

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

THE ZSH/EXAMPLE MODULE

       The zsh/example module makes available one builtin command:

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

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

THE ZSH/FILES MODULE

       The   zsh/files  module  makes  some  standard  commands  available  as
       builtins:

       chgrp [ -Rs ] group filename ...
              Changes group of files specified.  This is equivalent  to  chown
              with a user-spec argument of ‘:group’.

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

              The user-spec can be in four forms:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       rmdir dir ...
              Removes empty directories specified.

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

THE ZSH/MAPFILE MODULE

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

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

              When the array is accessed as a whole, the keys are the names of
              files  in  the  current  directory, and the values are empty (to
              save a huge overhead in memory).   Thus  ${(k)mapfile}  has  the
              same  affect  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.

   Limitations
       Although  reading  and  writing  of the file in question is efficiently
       handled, zsh’s internal memory management may be  arbitrarily  baroque.
       Thus  it  should  not  automatically  be  assumed  that  use of mapfile
       represents a gain in efficiency over use of other mechanisms.  Note  in
       particular  that  the  whole  contents  of  the file will always reside
       physically in memory when accessed (possibly  multiple  times,  due  to
       standard parameter substitution operations).  In particular, this means
       handling of sufficiently long files (greater than  the  machine’s  swap
       space, or than the range of the pointer type) will be incorrect.

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

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

THE ZSH/MATHFUNC MODULE

       The  zsh/mathfunc  module  provides standard mathematical functions for
       use when evaluating mathematical  formulae.   The  syntax  agrees  with
       normal C and FORTRAN conventions, for example,

              (( f = sin(0.3) ))

       assigns the sine of 0.3 to the parameter f.

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

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

       The  function signgam takes no arguments, and returns an integer, which
       is the C variable of the same name, as  described  in  gamma(3).   Note
       that  it  is therefore only useful immediately after a call to gamma or
       lgamma.  Note also  that  ‘signgam(RPAR’  and  ‘signgam’  are  distinct
       expressions.

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

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

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

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

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

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

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

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

       For example, consider

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

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

THE ZSH/NEWUSER MODULE

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

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

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

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

       The zsh/newuser module is then unconditionally unloaded.

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

THE ZSH/PARAMETER MODULE

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

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

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

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

       dis_functions
              Like functions but for disabled functions.

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

       dis_builtins
              Like builtins but for disabled builtin commands.

       reswords
              This array contains the enabled reserved words.

       dis_reswords
              Like reswords but for disabled reserved words.

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

       dis_aliases
              Like aliases but for disabled regular aliases.

       galiases
              Like aliases, but for global aliases.

       dis_galiases
              Like galiases but for disabled global aliases.

       saliases
              Like raliases, but for suffix aliases.

       dis_saliases
              Like saliases but for disabled suffix aliases.

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

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

              Setting or unsetting keys in this array is not possible.

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

       history
              This associative array maps history event numbers  to  the  full
              history lines.

       historywords
              A special array containing the words stored in the history.

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

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

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

       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.

       funcstack
              This array contains the names of the functions  currently  being
              executed.  The  first  element is the name of the function using
              the parameter.

       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.

THE ZSH/PCRE MODULE

       The zsh/pcre module makes some commands available as builtins:

       pcre_compile [ -aimx ] 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.

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

       pcre_match [ -a arr ] string
              Returns  successfully  if string matches the previously-compiled
              PCRE.

              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.

       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".

THE ZSH/SCHED MODULE

       The zsh/sched module makes available one builtin command:

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

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

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

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

THE ZSH/NET/SOCKET MODULE

       The zsh/net/socket module makes available one builtin command:

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

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

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

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

   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.

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

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

       zsocket -a [ -tv ] [ -d targetfd ] listenfd
              zsocket  -a  will  accept  an  incoming connection to the socket
              associated with listenfd.  The shell parameter REPLY will be set
              to the file descriptor associated with the inbound connection.

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

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

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

THE ZSH/STAT MODULE

       The zsh/stat module makes available one builtin command:

       stat  [  -gnNolLtTrs  ] [ -f fd ] [ -H hash ] [ -A array ] [ -F fmt ] [
       +element ] [ file ... ]
              The  command  acts  as  a front end to the stat system call (see
              stat(2)).  If the stat call fails, the appropriate system  error
              message  printed and status 1 is returned.  The fields of struct
              stat give information about the files provided as  arguments  to
              the command.  In addition to those available from the stat call,
              an extra element ‘link’ is provided.  These elements are:

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

              inode  The unique number of the file  on  this  device  (‘inode’
                     number).

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

              nlink  The number of hard links to the file.

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

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

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

              size   The size of the file in bytes.

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

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

              block  The number of disk blocks used by the file.

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

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

              Options:

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

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

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

              -F fmt Supplies a strftime  (see  strftime(3))  string  for  the
                     formatting  of  the  time  elements.   The  -s  option is
                     implied.

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

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

              -L     Perform an lstat (see lstat(2)) rather than a stat system
                     call.  In this case, if the file is a  link,  information
                     about  the  link  itself  rather  than the target file is
                     returned.  This option  is  required  to  make  the  link
                     element useful.

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

              -N     Never show the names of files.

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

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

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

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

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

THE ZSH/SYSTEM MODULE

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

BUILTINS

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

PARAMETERS

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

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

       sysparams
              A readonly associative array.  The keys are:
       pid    Returns  the  process  ID  of  the  current  process,  even   in
              subshells.  Compare $$, which returns the process ID of the main
              shell process.

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

THE ZSH/NET/TCP MODULE

       The zsh/net/tcp module makes available one builtin command:

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

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

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

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

              Connection type
                     A letter indicating how the session was created:

                      Z      A session created with the zftp command.

                      L      A connection opened for listening with ‘ztcp -l’.

                      I      An inbound connection accepted with ‘ztcp -a’.

                      O      An  outbound  connection  created with ‘ztcp host
                             ...’.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

THE ZSH/TERMCAP MODULE

       The zsh/termcap module makes available one builtin command:

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

       The zsh/termcap module makes available one parameter:

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

THE ZSH/TERMINFO MODULE

       The zsh/terminfo module makes available one builtin command:

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

       The zsh/terminfo module makes available one parameter:

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

THE ZSH/ZFTP MODULE

       The zsh/zftp module makes available one builtin command:

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

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

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

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

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

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

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

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

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

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

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

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

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

              For example,

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

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

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

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

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

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

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

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

       ls [ args ]
              Give a (short) listing of the remote directory.  With  no  args,
              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 files...
       local [ files... ]
              Print the size and last modification time of the remote or local
              files.  If there is more than one item on the list, the name  of
              the  file  is printed first.  The first number is the file size,
              the second is the last modification time  of  the  file  in  the
              format  CCYYMMDDhhmmSS  consisting  of  year, month, date, hour,
              minutes and seconds in GMT.  Note that  this  format,  including
              the  length, is guaranteed, so that time strings can be directly
              compared via the [[ builtin’s < and > operators,  even  if  they
              are too long to be represented as integers.

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

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

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

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

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

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

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

       mkdir directory
              Create a new directory directory on the server.

       rmdir directory
              Delete the directory directory  on the server.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       ZFTP_PWD
              Readonly.  The current directory on the server.

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

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

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

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

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

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

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

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

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

              1.     A positive preliminary reply.

              2.     A positive completion reply.

              3.     A positive intermediate reply.

              4.     A transient negative completion reply.

              5.     A permanent negative completion reply.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

THE ZSH/ZLE MODULE

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

THE ZSH/ZLEPARAMETER MODULE

       The  zsh/zleparameter module defines two special parameters that can be
       used to access  internal  information  of  the  Zsh  Line  Editor  (see
       zshzle(1)).

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

       widgets
              This associative array contains one entry  per  widget  defined.
              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, or it is a string of the form
              ‘completion:type:name’, for completion widgets. In the last case
              type  is  the  name of the builtin widgets the completion widget
              imitates in its behavior and name  is  the  name  of  the  shell
              function implementing the completion widget.

THE ZSH/ZPROF MODULE

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

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

              At the top there is a summary listing all  functions  that  were
              called  at  least  once.   This  summary is sorted in decreasing
              order of the amount of time spent in each.   The  lines  contain
              the  number  of  the  function  in order, which is used in other
              parts of the list in suffixes of the form ‘[num]’.RE,  then  the
              number  of  calls  made to the function.  The next three columns
              list the time in milliseconds spent  in  the  function  and  its
              descendents,  the  average  time  in  milliseconds  spent in the
              function and its descendents per call and the percentage of time
              spent  in  all  shell  functions  used  in this function and its
              descendents.   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 descendents.  Each
              of these entries consists of descriptions for the functions that
              called the function described,  the  function  itself,  and  the
              functions  that  were  called  from it.  The description for the
              function itself has the same format as in the summary (and shows
              the same information).  The other lines don’t show the number of
              the function at the beginning  and  have  their  function  named
              indented  to  make it easier to distinguish the line showing the
              function described in the section from the surrounding lines.

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

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

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

THE ZSH/ZPTY MODULE

       The zsh/zpty module offers one builtin:

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

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

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

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

       zpty -w [ -n ] name [ strings ... ]
              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 strings are 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.

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

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

              If a pattern is given as well, output is read  until  the  whole
              string  read matches the pattern, even in the non-blocking case.
              The return status  is  zero  if  the  string  read  matches  the
              pattern, or if the command has exited but at least one character
              could still be read.  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.

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

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

THE ZSH/ZSELECT MODULE

       The zsh/zselect module makes available one builtin command:

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

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

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

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

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

                     zselect -t 0 -r 0 -w 1

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

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

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

THE ZSH/ZUTIL MODULE

       The zsh/zutil module only adds some builtins:

       zstyle [ -L [ pattern [ style ] ] ]
       zstyle [ -e | - | -- ] pattern style strings ...
       zstyle -d [ pattern [ styles ... ] ]
       zstyle -g name [ pattern [ style ] ]
       zstyle -abs context style name [ sep ]
       zstyle -Tt context style [ strings ...]
       zstyle -m context style pattern
              This builtin command  is  used  to  define  and  lookup  styles.
              Styles  are  pairs of names and values, where the values consist
              of any  number  of  strings.   They  are  stored  together  with
              patterns  and  lookup  is  done  by  giving a string, called the
              ‘context’, which is compared to the  patterns.   The  definition
              stored for the first matching pattern will be returned.

              For  ordering  of  comparisons,  patterns are searched from most
              specific to  least  specific,  and  patterns  that  are  equally
              specific  keep  the order in which they were defined.  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 ‘*’.

              The  first form (without arguments) lists the definitions 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 is a pattern which will
              be matched against the string supplied as the  pattern  for  the
              context;   note   that  this  means,  for  example,  ‘zstyle  -L
              ":completion:*"’  will  match  any  supplied  pattern  beginning
              ‘:completion:’,  not just ":completion:*":  use ":completion:\*"
              to match that.  The optional second argument limits  the  output
              to  a specific style (not a pattern).  -L is not compatible with
              any other options.

              The other forms are the following:

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

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

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

              The other forms can be used to look up or test patterns.

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

              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’.

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

              zstyle -t context style [ strings ...]
              zstyle -T context style [ strings ...]
                     Test  the  value  of  a  style,  i.e.  the -t option only
                     returns a status (sets  $?).   Without  any  strings  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  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 specs ...
       zformat -a array sep specs ...
              This builtin provides two different  forms  of  formatting.  The
              first  form  is  selected  with  the -f option. In this case the
              format string will be modified by replacing  sequences  starting
              with  a  percent  sign  in it with strings from the specs.  Each
              spec should be of the form ‘char:string’ which will cause  every
              appearance  of  the sequence ‘%char’ in format to be replaced by
              the string.  The ‘%’ sequence may also contain optional  minimum
              and  maximum  field width specifications between the ‘%’ and the
              ‘char’ in the form ‘%min.maxc’, i.e. the minimum field width  is
              given first and if the maximum field width is used, it has to be
              preceded by a dot.  Specifying a minimum field width  makes  the
              result  be  padded  with  spaces  to  the right if the string is
              shorter than the requested width.  Padding to the  left  can  be
              achieved by giving a negative minimum field width.  If a maximum
              field width is specified, the string  will  be  truncated  after
              that  many  characters.   After  all ‘%’ sequences for the given
              specs have been processed, the resulting string is stored in the
              parameter param.

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

              For example:

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

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

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

       zregexparse
              This implements some internals of the _regex_arguments function.

       zparseopts [ -D ] [ -K ] [ -E ] [ -a array ] [ -A assoc ] specs
              This builtin simplifies the parsing  of  options  in  positional
              parameters,  i.e.  the  set of arguments given by $*.  Each spec
              describes one option and must be of the form ‘opt[=array]’.   If
              an option described by opt is found in the positional parameters
              it is copied into the array specified with the -a option; if the
              optional  ‘=array’  is  given,  it  is  instead copied into that
              array.

              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 ‘--’.

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

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

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

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

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

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

                     A  ‘+’ as described above may appear between the name and
                     the first colon.

       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.  This is
              similar to using the shift builtin.

       -K     With this option, the  arrays  specified  with  the  -a  and  -A
              options and with the ‘=array’ forms are kept unchanged when none
              of the specs for  them  is  used.   This  allows  assignment  of
              default values to them before calling zparseopts.

       -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.

       For example,

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

       will have the effect of

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

       The arguments from ‘baz’ on will not be used.

       As an example for the -E option, consider:

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

       will have the effect of

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

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