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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      zsh - the Z shell

      Because zsh contains many features, the zsh manual has been split into
      a number of sections:

      zsh          Zsh overview (this section)
      zshroadmap   Informal introduction to the manual
      zshmisc      Anything not fitting into the other sections
      zshexpn      Zsh command and parameter expansion
      zshparam     Zsh parameters
      zshoptions   Zsh options
      zshbuiltins  Zsh built-in functions
      zshzle       Zsh command line editing
      zshcompwid   Zsh completion widgets
      zshcompsys   Zsh completion system
      zshcompctl   Zsh completion control
      zshmodules   Zsh loadable modules
      zshcalsys    Zsh built-in calendar functions
      zshtcpsys    Zsh built-in TCP functions
      zshzftpsys   Zsh built-in FTP client
      zshcontrib   Additional zsh functions and utilities
      zshall       Meta-man page containing all of the above

      Zsh is a UNIX command interpreter (shell) usable as an interactive
      login shell and as a shell script command processor.  Of the standard
      shells, zsh most closely resembles ksh but includes many enhancements.
      It does not provide compatibility with POSIX or other shells in its
      default operating mode:  see the section `Compatibility' below.

      Zsh has command line editing, builtin spelling correction,
      programmable command completion, shell functions (with autoloading), a
      history mechanism, and a host of other features.

      Zsh was originally written by Paul Falstad.  Zsh is now maintained by
      the members of the zsh-workers mailing list <>.
      The development is currently coordinated by Peter Stephenson
      <>.  The coordinator can be contacted at
      <>, but matters relating to the code should
      generally go to the mailing list.

      Zsh is available from the following HTTP and anonymous FTP site.

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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      The up-to-date source code is available via Git from Sourceforge.  See for details.  A summary of
      instructions for the archive can be found at

      Zsh has several mailing lists:

           Announcements about releases, major changes in the shell and the
           monthly posting of the Zsh FAQ.  (moderated)

           User discussions.

           Hacking, development, bug reports and patches.

           Private mailing list (the general public cannot subscribe to it)
           for discussing bug reports with security implications, i.e.,
           potential vulnerabilities.

           If you find a security problem in zsh itself, please mail this

      To subscribe or unsubscribe, send mail to the associated
      administrative address for the mailing list.


      All submissions to zsh-announce are automatically forwarded to
      zsh-users.  All submissions to zsh-users are automatically forwarded
      to zsh-workers.

      If you have problems subscribing/unsubscribing to any of the mailing
      lists, send mail to <>.

      The mailing lists are archived; the archives can be accessed via the
      administrative addresses listed above.  There is also a hypertext
      archive available at

      Zsh has a list of Frequently Asked Questions (FAQ), maintained by
      Peter Stephenson <>.  It is regularly posted to the

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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      newsgroup and the zsh-announce mailing list.  The
      latest version can be found at any of the Zsh FTP sites, or at  The contact address for FAQ-related matters
      is <>.

      Zsh has a web page which is located at  The
      contact address for web-related matters is <>.

      A userguide is currently in preparation.  It is intended to complement
      the manual, with explanations and hints on issues where the manual can
      be cabbalistic, hierographic, or downright mystifying (for example,
      the word `hierographic' does not exist).  It can be viewed in its
      current state at  At the time of
      writing, chapters dealing with startup files and their contents and
      the new completion system were essentially complete.

      The following flags are interpreted by the shell when invoked to
      determine where the shell will read commands from:

      -c   Take the first argument as a command to execute, rather than
           reading commands from a script or standard input.  If any further
           arguments are given, the first one is assigned to $0, rather than
           being used as a positional parameter.

      -i   Force shell to be interactive.  It is still possible to specify a
           script to execute.

      -s   Force shell to read commands from the standard input.  If the -s
           flag is not present and an argument is given, the first argument
           is taken to be the pathname of a script to execute.

      If there are any remaining arguments after option processing, and
      neither of the options -c or -s was supplied, the first argument is
      taken as the file name of a script containing shell commands to be
      executed.  If the option PATH_SCRIPT is set, and the file name does
      not contain a directory path (i.e. there is no `/' in the name), first
      the current directory and then the command path given by the variable
      PATH are searched for the script.  If the option is not set or the
      file name contains a `/' it is used directly.

      After the first one or two arguments have been appropriated as
      described above, the remaining arguments are assigned to the
      positional parameters.

      For further options, which are common to invocation and the set
      builtin, see zshoptions(1).

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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      The long option `--emulate' followed (in a separate word) by an
      emulation mode may be passed to the shell.  The emulation modes are
      those described for the emulate builtin, see zshbuiltins(1).  The
      `--emulate' option must precede any other options (which might
      otherwise be overridden), but following options are honoured, so may
      be used to modify the requested emulation mode.  Note that certain
      extra steps are taken to ensure a smooth emulation when this option is
      used compared with the emulate command within the shell: for example,
      variables that conflict with POSIX usage such as path are not defined
      within the shell.

      Options may be specified by name using the -o option.  -o acts like a
      single-letter option, but takes a following string as the option name.
      For example,

           zsh -x -o shwordsplit scr

      runs the script scr, setting the XTRACE option by the corresponding
      letter `-x' and the SH_WORD_SPLIT option by name.  Options may be
      turned off by name by using +o instead of -o.  -o can be stacked up
      with preceding single-letter options, so for example `-xo shwordsplit'
      or `-xoshwordsplit' is equivalent to `-x -o shwordsplit'.

      Options may also be specified by name in GNU long option style,
      `--option-name'.  When this is done, `-' characters in the option name
      are permitted: they are translated into `_', and thus ignored.  So,
      for example, `zsh --sh-word-split' invokes zsh with the SH_WORD_SPLIT
      option turned on.  Like other option syntaxes, options can be turned
      off by replacing the initial `-' with a `+'; thus `+-sh-word-split' is
      equivalent to `--no-sh-word-split'.  Unlike other option syntaxes,
      GNU-style long options cannot be stacked with any other options, so
      for example `-x-shwordsplit' is an error, rather than being treated
      like `-x --shwordsplit'.

      The special GNU-style option `--version' is handled; it sends to
      standard output the shell's version information, then exits
      successfully.  `--help' is also handled; it sends to standard output a
      list of options that can be used when invoking the shell, then exits

      Option processing may be finished, allowing following arguments that
      start with `-' or `+' to be treated as normal arguments, in two ways.
      Firstly, a lone `-' (or `+') as an argument by itself ends option
      processing.  Secondly, a special option `--' (or `+-'), which may be
      specified on its own (which is the standard POSIX usage) or may be
      stacked with preceding options (so `-x-' is equivalent to `-x --').
      Options are not permitted to be stacked after `--' (so `-x-f' is an
      error), but note the GNU-style option form discussed above, where
      `--shwordsplit' is permitted and does not end option processing.

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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      Except when the sh/ksh emulation single-letter options are in effect,
      the option `-b' (or `+b') ends option processing.  `-b' is like `--',
      except that further single-letter options can be stacked after the
      `-b' and will take effect as normal.

      Zsh tries to emulate sh or ksh when it is invoked as sh or ksh
      respectively; more precisely, it looks at the first letter of the name
      by which it was invoked, excluding any initial `r' (assumed to stand
      for `restricted'), and if that is `b', `s' or `k' it will emulate sh
      or ksh.  Furthermore, if invoked as su (which happens on certain
      systems when the shell is executed by the su command), the shell will
      try to find an alternative name from the SHELL environment variable
      and perform emulation based on that.

      In sh and ksh compatibility modes the following parameters are not
      special and not initialized by the shell: ARGC, argv, cdpath, fignore,
      fpath, HISTCHARS, mailpath, MANPATH, manpath, path, prompt, PROMPT,
      PROMPT2, PROMPT3, PROMPT4, psvar, status.

      The usual zsh startup/shutdown scripts are not executed.  Login shells
      source /etc/profile followed by $HOME/.profile.  If the ENV
      environment variable is set on invocation, $ENV is sourced after the
      profile scripts.  The value of ENV is subjected to parameter
      expansion, command substitution, and arithmetic expansion before being
      interpreted as a pathname.  Note that the PRIVILEGED option also
      affects the execution of startup files.

      The following options are set if the shell is invoked as sh or ksh:
      and IGNORE_BRACES options are set if zsh is invoked as sh.  Also, the
      SINGLE_LINE_ZLE options are set if zsh is invoked as ksh.

      Please note that, whilst reasonable efforts are taken to address
      incompatibilities when they arise, zsh does not guarantee complete
      emulation of other shells, nor POSIX compliance. For more information
      on the differences between zsh and other shells, please refer to
      chapter2 of the shell FAQ,

      When the basename of the command used to invoke zsh starts with the
      letter `r' or the `-r' command line option is supplied at invocation,
      the shell becomes restricted.  Emulation mode is determined after
      stripping the letter `r' from the invocation name.  The following are
      disabled in restricted mode:

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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      +    changing directories with the cd builtin

      +    changing or unsetting the EGID, EUID, GID, HISTFILE, HISTSIZE,
           LD_PRELOAD, MODULE_PATH, module_path, PATH, path, SHELL, UID and
           USERNAME parameters

      +    specifying command names containing /

      +    specifying command pathnames using hash

      +    redirecting output to files

      +    using the exec builtin command to replace the shell with another

      +    using jobs -Z to overwrite the shell process' argument and
           environment space

      +    using the ARGV0 parameter to override argv[0] for external

      +    turning off restricted mode with set +r or unsetopt RESTRICTED

      These restrictions are enforced after processing the startup files.
      The startup files should set up PATH to point to a directory of
      commands which can be safely invoked in the restricted environment.
      They may also add further restrictions by disabling selected builtins.

      Restricted mode can also be activated any time by setting the
      RESTRICTED option.  This immediately enables all the restrictions
      described above even if the shell still has not processed all startup

      A shell Restricted Mode is an outdated way to restrict what users may
      do:  modern systems have better, safer and more reliable ways to
      confine user actions, such as chroot jails, containers and zones.

      A restricted shell is very difficult to implement safely.  The feature
      may be removed in a future version of zsh.

      It is important to realise that the restrictions only apply to the
      shell, not to the commands it runs (except for some shell builtins).
      While a restricted shell can only run the restricted list of commands
      accessible via the predefined `PATH' variable, it does not prevent
      those commands from running any other command.

      As an example, if `env' is among the list of allowed commands, then it
      allows the user to run any command as `env' is not a shell builtin
      command and can run arbitrary executables.

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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      So when implementing a restricted shell framework it is important to
      be fully aware of what actions each of the allowed commands or
      features (which may be regarded as modules) can perform.

      Many commands can have their behaviour affected by environment
      variables.  Except for the few listed above, zsh does not restrict the
      setting of environment variables.

      If a `perl', `python', `bash', or other general purpose interpreted
      script it treated as a restricted command, the user can work around
      the restriction by setting specially crafted `PERL5LIB', `PYTHONPATH',
      `BASHENV' (etc.) environment variables. On GNU systems, any command
      can be made to run arbitrary code when performing character set
      conversion (including zsh itself) by setting a `GCONV_PATH'
      environment variable.  Those are only a few examples.

      Bear in mind that, contrary to some other shells, `readonly' is not a
      security feature in zsh as it can be undone and so cannot be used to
      mitigate the above.

      A restricted shell only works if the allowed commands are few and
      carefully written so as not to grant more access to users than
      intended.  It is also important to restrict what zsh module the user
      may load as some of them, such as `zsh/system', `zsh/mapfile' and
      `zsh/files', allow bypassing most of the restrictions.

      Commands are first read from /etc/zshenv; this cannot be overridden.
      Subsequent behaviour is modified by the RCS and GLOBAL_RCS options;
      the former affects all startup files, while the second only affects
      global startup files (those shown here with an path starting with a
      /).  If one of the options is unset at any point, any subsequent
      startup file(s) of the corresponding type will not be read.  It is
      also possible for a file in $ZDOTDIR to re-enable GLOBAL_RCS. Both RCS
      and GLOBAL_RCS are set by default.

      Commands are then read from $ZDOTDIR/.zshenv.  If the shell is a login
      shell, commands are read from /etc/zprofile and then
      $ZDOTDIR/.zprofile.  Then, if the shell is interactive, commands are
      read from /etc/zshrc and then $ZDOTDIR/.zshrc.  Finally, if the shell
      is a login shell, /etc/zlogin and $ZDOTDIR/.zlogin are read.

      When a login shell exits, the files $ZDOTDIR/.zlogout and then
      /etc/zlogout are read.  This happens with either an explicit exit via
      the exit or logout commands, or an implicit exit by reading
      end-of-file from the terminal.  However, if the shell terminates due
      to exec'ing another process, the logout files are not read.  These are
      also affected by the RCS and GLOBAL_RCS options.  Note also that the
      RCS option affects the saving of history files, i.e. if RCS is unset
      when the shell exits, no history file will be saved.

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 ZSH(1)                            zsh 5.9                            ZSH(1)
                                May 14, 2022

      If ZDOTDIR is unset, HOME is used instead.  Files listed above as
      being in /etc may be in another directory, depending on the

      As /etc/zshenv is run for all instances of zsh, it is important that
      it be kept as small as possible.  In particular, it is a good idea to
      put code that does not need to be run for every single shell behind a
      test of the form `if [[ -o rcs ]]; then ...' so that it will not be
      executed when zsh is invoked with the `-f' option.

      Any of these files may be pre-compiled with the zcompile builtin
      command (see zshbuiltins(1)).  If a compiled file exists (named for
      the original file plus the .zwc extension) and it is newer than the
      original file, the compiled file will be used instead.

      ${TMPPREFIX}*   (default is /tmp/zsh*)
      /etc/zlogout    (installation-specific - /etc is the default)

      sh(1), csh(1), tcsh(1), rc(1), bash(1), ksh(1), zshall(1),
      zshbuiltins(1), zshcalsys(1), zshcompwid(1), zshcompsys(1),
      zshcompctl(1), zshcontrib(1), zshexpn(1), zshmisc(1), zshmodules(1),
      zshoptions(1), zshparam(1), zshroadmap(1), zshtcpsys(1),
      zshzftpsys(1), zshzle(1)

      IEEE Standard for information Technology - Portable Operating System
      Interface (POSIX) - Part 2: Shell and Utilities, IEEE Inc, 1993, ISBN

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