1ZSH(1) General Commands Manual ZSH(1)
2
6 zsh - the Z shell
7
9 Because zsh contains many features, the zsh manual has been split into
10 a number of sections:
11 zsh Zsh overview (this section)
13 zshroadmap Informal introduction to the manual
14 zshmisc Anything not fitting into the other sections
15 zshexpn Zsh command and parameter expansion
16 zshparam Zsh parameters
17 zshoptions Zsh options
18 zshbuiltins Zsh built-in functions
19 zshzle Zsh command line editing
20 zshcompwid Zsh completion widgets
21 zshcompsys Zsh completion system
22 zshcompctl Zsh completion control
23 zshmodules Zsh loadable modules
24 zshcalsys Zsh built-in calendar functions
25 zshtcpsys Zsh built-in TCP functions
26 zshzftpsys Zsh built-in FTP client
27 zshcontrib Additional zsh functions and utilities
28 zshall Meta-man page containing all of the above
29
31 Zsh is a UNIX command interpreter (shell) usable as an interactive
32 login shell and as a shell script command processor. Of the standard
33 shells, zsh most closely resembles ksh but includes many enhancements.
34 It does not provide compatibility with POSIX or other shells in its
35 default operating mode: see the section Compatibility below.
36 Zsh has command line editing, builtin spelling correction, programmable
38 command completion, shell functions (with autoloading), a history mech‐
39 anism, and a host of other features.
40
42 Zsh was originally written by Paul Falstad <pf@zsh.org>. Zsh is now
43 maintained by the members of the zsh-workers mailing list <zsh-work‐
44 ers@zsh.org>. The development is currently coordinated by Peter
45 Stephenson <pws@zsh.org>. The coordinator can be contacted at <coordi‐
46 nator@zsh.org>, but matters relating to the code should generally go to
47 the mailing list.
48
50 Zsh is available from the following HTTP and anonymous FTP site.
51 ftp://ftp.zsh.org/pub/
53 https://www.zsh.org/pub/
54 )
55 The up-to-date source code is available via Git from Sourceforge. See
57 https://sourceforge.net/projects/zsh/ for details. A summary of
58 instructions for the archive can be found at http://zsh.source‐
59 forge.net/.
60
62 Zsh has 3 mailing lists:
63 <zsh-announce@zsh.org>
65 Announcements about releases, major changes in the shell and the
66 monthly posting of the Zsh FAQ. (moderated)
67 <zsh-users@zsh.org>
69 User discussions.
70 <zsh-workers@zsh.org>
72 Hacking, development, bug reports and patches.
73 To subscribe or unsubscribe, send mail to the associated administrative
75 address for the mailing list.
76 <zsh-announce-subscribe@zsh.org>
78 <zsh-users-subscribe@zsh.org>
79 <zsh-workers-subscribe@zsh.org>
80 <zsh-announce-unsubscribe@zsh.org>
81 <zsh-users-unsubscribe@zsh.org>
82 <zsh-workers-unsubscribe@zsh.org>
83 YOU ONLY NEED TO JOIN ONE OF THE MAILING LISTS AS THEY ARE NESTED. All
85 submissions to zsh-announce are automatically forwarded to zsh-users.
86 All submissions to zsh-users are automatically forwarded to zsh-work‐
87 ers.
88 If you have problems subscribing/unsubscribing to any of the mailing
90 lists, send mail to <listmaster@zsh.org>. The mailing lists are main‐
91 tained by Karsten Thygesen <karthy@kom.auc.dk>.
92 The mailing lists are archived; the archives can be accessed via the
94 administrative addresses listed above. There is also a hypertext ar‐
95 chive, maintained by Geoff Wing <gcw@zsh.org>, available at
96 https://www.zsh.org/mla/.
97
99 Zsh has a list of Frequently Asked Questions (FAQ), maintained by Peter
100 Stephenson <pws@zsh.org>. It is regularly posted to the newsgroup
101 comp.unix.shell and the zsh-announce mailing list. The latest version
102 can be found at any of the Zsh FTP sites, or at
103 http://www.zsh.org/FAQ/. The contact address for FAQ-related matters
104 is <faqmaster@zsh.org>.
105
107 Zsh has a web page which is located at https://www.zsh.org/. This is
108 maintained by Karsten Thygesen <karthy@zsh.org>, of SunSITE Denmark.
109 The contact address for web-related matters is <webmaster@zsh.org>.
110
112 A userguide is currently in preparation. It is intended to complement
113 the manual, with explanations and hints on issues where the manual can
114 be cabbalistic, hierographic, or downright mystifying (for example, the
115 word `hierographic' does not exist). It can be viewed in its current
116 state at http://zsh.sourceforge.net/Guide/. At the time of writing,
117 chapters dealing with startup files and their contents and the new com‐
118 pletion system were essentially complete.
119
121 The following flags are interpreted by the shell when invoked to deter‐
122 mine where the shell will read commands from:
123 -c Take the first argument as a command to execute, rather than
125 reading commands from a script or standard input. If any fur‐
126 ther arguments are given, the first one is assigned to $0,
127 rather than being used as a positional parameter.
128 -i Force shell to be interactive. It is still possible to specify
130 a script to execute.
131 -s Force shell to read commands from the standard input. If the -s
133 flag is not present and an argument is given, the first argument
134 is taken to be the pathname of a script to execute.
135 If there are any remaining arguments after option processing, and nei‐
137 ther of the options -c or -s was supplied, the first argument is taken
138 as the file name of a script containing shell commands to be executed.
139 If the option PATH_SCRIPT is set, and the file name does not contain a
140 directory path (i.e. there is no `/' in the name), first the current
141 directory and then the command path given by the variable PATH are
142 searched for the script. If the option is not set or the file name
143 contains a `/' it is used directly.
144 After the first one or two arguments have been appropriated as
146 described above, the remaining arguments are assigned to the positional
147 parameters.
148 For further options, which are common to invocation and the set
150 builtin, see zshoptions(1).
151 The long option `--emulate' followed (in a separate word) by an emula‐
153 tion mode may be passed to the shell. The emulation modes are those
154 described for the emulate builtin, see zshbuiltins(1). The `--emulate'
155 option must precede any other options (which might otherwise be over‐
156 ridden), but following options are honoured, so may be used to modify
157 the requested emulation mode. Note that certain extra steps are taken
158 to ensure a smooth emulation when this option is used compared with the
159 emulate command within the shell: for example, variables that conflict
160 with POSIX usage such as path are not defined within the shell.
161 Options may be specified by name using the -o option. -o acts like a
163 single-letter option, but takes a following string as the option name.
164 For example,
165 zsh -x -o shwordsplit scr
167 runs the script scr, setting the XTRACE option by the corresponding
169 letter `-x' and the SH_WORD_SPLIT option by name. Options may be
170 turned off by name by using +o instead of -o. -o can be stacked up
171 with preceding single-letter options, so for example `-xo shwordsplit'
172 or `-xoshwordsplit' is equivalent to `-x -o shwordsplit'.
173 Options may also be specified by name in GNU long option style,
175 `--option-name'. When this is done, `-' characters in the option name
176 are permitted: they are translated into `_', and thus ignored. So, for
177 example, `zsh --sh-word-split' invokes zsh with the SH_WORD_SPLIT
178 option turned on. Like other option syntaxes, options can be turned
179 off by replacing the initial `-' with a `+'; thus `+-sh-word-split' is
180 equivalent to `--no-sh-word-split'. Unlike other option syntaxes,
181 GNU-style long options cannot be stacked with any other options, so for
182 example `-x-shwordsplit' is an error, rather than being treated like
183 `-x --shwordsplit'.
184 The special GNU-style option `--version' is handled; it sends to stan‐
186 dard output the shell's version information, then exits successfully.
187 `--help' is also handled; it sends to standard output a list of options
188 that can be used when invoking the shell, then exits successfully.
189 Option processing may be finished, allowing following arguments that
191 start with `-' or `+' to be treated as normal arguments, in two ways.
192 Firstly, a lone `-' (or `+') as an argument by itself ends option pro‐
193 cessing. Secondly, a special option `--' (or `+-'), which may be spec‐
194 ified on its own (which is the standard POSIX usage) or may be stacked
195 with preceding options (so `-x-' is equivalent to `-x --'). Options
196 are not permitted to be stacked after `--' (so `-x-f' is an error), but
197 note the GNU-style option form discussed above, where `--shwordsplit'
198 is permitted and does not end option processing.
199 Except when the sh/ksh emulation single-letter options are in effect,
201 the option `-b' (or `+b') ends option processing. `-b' is like `--',
202 except that further single-letter options can be stacked after the `-b'
203 and will take effect as normal.
204
206 Zsh tries to emulate sh or ksh when it is invoked as sh or ksh respec‐
207 tively; more precisely, it looks at the first letter of the name by
208 which it was invoked, excluding any initial `r' (assumed to stand for
209 `restricted'), and if that is `b', `s' or `k' it will emulate sh or
210 ksh. Furthermore, if invoked as su (which happens on certain systems
211 when the shell is executed by the su command), the shell will try to
212 find an alternative name from the SHELL environment variable and per‐
213 form emulation based on that.
214 In sh and ksh compatibility modes the following parameters are not spe‐
216 cial and not initialized by the shell: ARGC, argv, cdpath, fignore,
217 fpath, HISTCHARS, mailpath, MANPATH, manpath, path, prompt, PROMPT,
218 PROMPT2, PROMPT3, PROMPT4, psvar, status, watch.
219 The usual zsh startup/shutdown scripts are not executed. Login shells
221 source /etc/profile followed by $HOME/.profile. If the ENV environment
222 variable is set on invocation, $ENV is sourced after the profile
223 scripts. The value of ENV is subjected to parameter expansion, command
224 substitution, and arithmetic expansion before being interpreted as a
225 pathname. Note that the PRIVILEGED option also affects the execution
226 of startup files.
227 The following options are set if the shell is invoked as sh or ksh:
229 NO_BAD_PATTERN, NO_BANG_HIST, NO_BG_NICE, NO_EQUALS, NO_FUNC‐
230 TION_ARGZERO, GLOB_SUBST, NO_GLOBAL_EXPORT, NO_HUP, INTERACTIVE_COM‐
231 MENTS, KSH_ARRAYS, NO_MULTIOS, NO_NOMATCH, NO_NOTIFY, POSIX_BUILTINS,
232 NO_PROMPT_PERCENT, RM_STAR_SILENT, SH_FILE_EXPANSION, SH_GLOB,
233 SH_OPTION_LETTERS, SH_WORD_SPLIT. Additionally the BSD_ECHO and
234 IGNORE_BRACES options are set if zsh is invoked as sh. Also, the
235 KSH_OPTION_PRINT, LOCAL_OPTIONS, PROMPT_BANG, PROMPT_SUBST and SIN‐
236 GLE_LINE_ZLE options are set if zsh is invoked as ksh.
237
239 When the basename of the command used to invoke zsh starts with the
240 letter `r' or the `-r' command line option is supplied at invocation,
241 the shell becomes restricted. Emulation mode is determined after
242 stripping the letter `r' from the invocation name. The following are
243 disabled in restricted mode:
244 · changing directories with the cd builtin
246 · changing or unsetting the EGID, EUID, GID, HISTFILE, HISTSIZE,
248 IFS, LD_AOUT_LIBRARY_PATH, LD_AOUT_PRELOAD, LD_LIBRARY_PATH,
249 LD_PRELOAD, MODULE_PATH, module_path, PATH, path, SHELL, UID and
250 USERNAME parameters
251 · specifying command names containing /
253 · specifying command pathnames using hash
255 · redirecting output to files
257 · using the exec builtin command to replace the shell with another
259 command
260 · using jobs -Z to overwrite the shell process' argument and envi‐
262 ronment space
263 · using the ARGV0 parameter to override argv[0] for external com‐
265 mands
266 · turning off restricted mode with set +r or unsetopt RESTRICTED
268 These restrictions are enforced after processing the startup files.
270 The startup files should set up PATH to point to a directory of com‐
271 mands which can be safely invoked in the restricted environment. They
272 may also add further restrictions by disabling selected builtins.
273 Restricted mode can also be activated any time by setting the
275 RESTRICTED option. This immediately enables all the restrictions
276 described above even if the shell still has not processed all startup
277 files.
278 A shell Restricted Mode is an outdated way to restrict what users may
280 do: modern systems have better, safer and more reliable ways to con‐
281 fine user actions, such as chroot jails, containers and zones.
282 A restricted shell is very difficult to implement safely. The feature
284 may be removed in a future version of zsh.
285 It is important to realise that the restrictions only apply to the
287 shell, not to the commands it runs (except for some shell builtins).
288 While a restricted shell can only run the restricted list of commands
289 accessible via the predefined `PATH' variable, it does not prevent
290 those commands from running any other command.
291 As an example, if `env' is among the list of allowed commands, then it
293 allows the user to run any command as `env' is not a shell builtin com‐
294 mand and can run arbitrary executables.
295 So when implementing a restricted shell framework it is important to be
297 fully aware of what actions each of the allowed commands or features
298 (which may be regarded as modules) can perform.
299 Many commands can have their behaviour affected by environment vari‐
301 ables. Except for the few listed above, zsh does not restrict the set‐
302 ting of environment variables.
303 If a `perl', `python', `bash', or other general purpose interpreted
305 script it treated as a restricted command, the user can work around the
306 restriction by setting specially crafted `PERL5LIB', `PYTHONPATH',
307 `BASHENV' (etc.) environment variables. On GNU systems, any command can
308 be made to run arbitrary code when performing character set conversion
309 (including zsh itself) by setting a `GCONV_PATH' environment variable.
310 Those are only a few examples.
311 Bear in mind that, contrary to some other shells, `readonly' is not a
313 security feature in zsh as it can be undone and so cannot be used to
314 mitigate the above.
315 A restricted shell only works if the allowed commands are few and care‐
317 fully written so as not to grant more access to users than intended.
318 It is also important to restrict what zsh module the user may load as
319 some of them, such as `zsh/system', `zsh/mapfile' and `zsh/files',
320 allow bypassing most of the restrictions.
321
323 Commands are first read from /etc/zshenv; this cannot be overridden.
324 Subsequent behaviour is modified by the RCS and GLOBAL_RCS options; the
325 former affects all startup files, while the second only affects global
326 startup files (those shown here with an path starting with a /). If
327 one of the options is unset at any point, any subsequent startup
328 file(s) of the corresponding type will not be read. It is also possi‐
329 ble for a file in $ZDOTDIR to re-enable GLOBAL_RCS. Both RCS and
330 GLOBAL_RCS are set by default.
331 Commands are then read from $ZDOTDIR/.zshenv. If the shell is a login
333 shell, commands are read from /etc/zprofile and then $ZDOTDIR/.zpro‐
334 file. Then, if the shell is interactive, commands are read from
335 /etc/zshrc and then $ZDOTDIR/.zshrc. Finally, if the shell is a login
336 shell, /etc/zlogin and $ZDOTDIR/.zlogin are read.
337 When a login shell exits, the files $ZDOTDIR/.zlogout and then
339 /etc/zlogout are read. This happens with either an explicit exit via
340 the exit or logout commands, or an implicit exit by reading end-of-file
341 from the terminal. However, if the shell terminates due to exec'ing
342 another process, the logout files are not read. These are also
343 affected by the RCS and GLOBAL_RCS options. Note also that the RCS
344 option affects the saving of history files, i.e. if RCS is unset when
345 the shell exits, no history file will be saved.
346 If ZDOTDIR is unset, HOME is used instead. Files listed above as being
348 in /etc may be in another directory, depending on the installation.
349 As /etc/zshenv is run for all instances of zsh, it is important that it
351 be kept as small as possible. In particular, it is a good idea to put
352 code that does not need to be run for every single shell behind a test
353 of the form `if [[ -o rcs ]]; then ...' so that it will not be executed
354 when zsh is invoked with the `-f' option.
355 Any of these files may be pre-compiled with the zcompile builtin com‐
357 mand (see zshbuiltins(1)). If a compiled file exists (named for the
358 original file plus the .zwc extension) and it is newer than the origi‐
359 nal file, the compiled file will be used instead.
360
362 $ZDOTDIR/.zshenv
363 $ZDOTDIR/.zprofile
364 $ZDOTDIR/.zshrc
365 $ZDOTDIR/.zlogin
366 $ZDOTDIR/.zlogout
367 ${TMPPREFIX}* (default is /tmp/zsh*)
368 /etc/zshenv
369 /etc/zprofile
370 /etc/zshrc
371 /etc/zlogin
372 /etc/zlogout (installation-specific - /etc is the default)
373
375 sh(1), csh(1), tcsh(1), rc(1), bash(1), ksh(1), zshall(1), zsh‐
376 builtins(1), zshcalsys(1), zshcompwid(1), zshcompsys(1), zshcompctl(1),
377 zshcontrib(1), zshexpn(1), zshmisc(1), zshmodules(1), zshoptions(1),
378 zshparam(1), zshroadmap(1), zshtcpsys(1), zshzftpsys(1), zshzle(1)
379 IEEE Standard for information Technology - Portable Operating System
381 Interface (POSIX) - Part 2: Shell and Utilities, IEEE Inc, 1993, ISBN
382 1-55937-255-9.
383zsh 5.8 February 14, 2020 ZSH(1)