Zsh: Difference between revisions

Revision as of 08:56, 9 April 2019

fa:Zsh Zsh is a powerful shell that operates as both an interactive shell and as a scripting language interpreter. While being compatible with Bash (not by default, only if issuing emulate sh), it offers advantages such as improved tab completion and globbing.

The Zsh FAQ offers more reasons to use Zsh.

Installation

Before starting, users may want to see what shell is currently being used:

$ echo $SHELL

Install the zsh package. For additional completion definitions, install the zsh-completions package as well.

Initial configuration

Make sure that Zsh has been installed correctly by running the following in a terminal:

$ zsh

You should now see zsh-newuser-install, which will walk you through some basic configuration. If you want to skip this, press q. If you did not see it, you can invoke it manually with

$ zsh /usr/share/zsh/functions/Newuser/zsh-newuser-install -f

Note: Make sure your terminal's size is at least 72×15 otherwise zsh-newuser-install will not run.

Making Zsh your default shell

See Command-line shell#Changing your default shell.

Tip: If replacing bash, users may want to move some code from ~/.bashrc to ~/.zshrc (e.g. the prompt and the aliases) and from ~/.bash_profile to ~/.zprofile (e.g. the code that starts the X Window System).

Startup/Shutdown files

Tip: See A User's Guide to the Z-Shell for explanation on interactive and login shells, and what to put in your startup files.

Note:

If $ZDOTDIR is not set, $HOME is used instead.
If option RCS is unset in any of the files, no configuration files will be sourced after that file.
If option GLOBAL_RCS is unset in any of the files, no global configuration files (/etc/zsh/*) will be sourced after that file.

When starting Zsh, it will source the following files in this order by default:

/etc/zsh/zshenv Used for setting system-wide environment variables; it should not contain commands that produce output or assume the shell is attached to a tty. This file will always be sourced, this cannot be overridden.
$ZDOTDIR/.zshenv Used for setting user's environment variables; it should not contain commands that produce output or assume the shell is attached to a tty. This file will always be sourced.
/etc/zsh/zprofile Used for executing commands at start, will be sourced when starting as a login shell. Please note that on Arch Linux, by default it contains one line which source the /etc/profile.
- /etc/profile This file should be sourced by all Bourne-compatible shells upon login: it sets up $PATH and other environment variables and application-specific (/etc/profile.d/*.sh) settings upon login.
$ZDOTDIR/.zprofile Used for executing user's commands at start, will be sourced when starting as a login shell.
/etc/zsh/zshrc Used for setting interactive shell configuration and executing commands, will be sourced when starting as an interactive shell.
$ZDOTDIR/.zshrc Used for setting user's interactive shell configuration and executing commands, will be sourced when starting as an interactive shell.
/etc/zsh/zlogin Used for executing commands at ending of initial progress, will be sourced when starting as a login shell.
$ZDOTDIR/.zlogin Used for executing user's commands at ending of initial progress, will be sourced when starting as a login shell.
$ZDOTDIR/.zlogout Will be sourced when a login shell exits.
/etc/zsh/zlogout Will be sourced when a login shell exits.

Note:

The paths used in Arch's zsh package are different from the default ones used in the man pages (FS#48992).

This article or section is out of date.

Reason: /etc/profile does not overwrite $PATH anymore, it appends Arch default path to $PATH. (Discuss in Talk:Zsh)

/etc/profile is not a part of the regular list of startup files run for Zsh, but is sourced from /etc/zsh/zprofile in the zsh package. Users should take note that /etc/profile sets the $PATH variable which will overwrite any $PATH variable set in $ZDOTDIR/.zshenv. To prevent this, please set the $PATH variable in $ZDOTDIR/.zprofile.

Warning: It is not recommended to replace the default one line in /etc/zsh/zprofile with something else, otherwise it will break the integrity of other packages which provide some scripts in /etc/profile.d/.

Configure Zsh

Although Zsh is usable out of the box, it is almost certainly not set up the way most users would like to use it, but due to the sheer amount of customization available in Zsh, configuring Zsh can be a daunting and time-consuming experience.

Simple .zshrc

Included below is a sample configuration file, it provides a decent set of default options as well as giving examples of many ways that Zsh can be customized. In order to use this configuration save it as a file named .zshrc.

Tip: Apply the changes without needing to logout and then back in by running source ~/.zshrc.

Here is a simple .zshrc:

~/.zshrc

autoload -Uz compinit promptinit
compinit
promptinit

# This will set the default prompt to the walters theme
prompt walters

Configuring $PATH

See A User's Guide to the Z-Shell and also the note in #Startup/Shutdown files for details.

The incantation typeset -U path, where the -U stands for unique, tells the shell that it should not add anything to $PATH if it is there already:

~/.zshenv

typeset -U path
path=(~/.local/bin /other/things/in/path $path[@])

Command completion

Perhaps the most compelling feature of Zsh is its advanced autocompletion abilities. At the very least, enable autocompletion in .zshrc. To enable autocompletion, add the following to your ~/.zshrc:

~/.zshrc

autoload -Uz compinit
compinit

The above configuration includes ssh/scp/sftp hostnames completion but in order for this feature to work, users must not enable ssh's hostname hashing (i.e. option HashKnownHosts in ssh client configuration).

For autocompletion with an arrow-key driven interface, add the following to:

~/.zshrc

zstyle ':completion:*' menu select

To activate the menu, press Tab twice.

For autocompletion of command line switches for aliases, add the following to:

~/.zshrc

setopt COMPLETE_ALIASES

For enabling autocompletion of privileged environments in privileged commands (e.g. if you complete a command starting with sudo, completion scripts will also try to determine your completions with sudo), include:

~/.zshrc

zstyle ':completion::complete:*' gain-privileges 1

Warning: This will let zsh completion scripts run commands with sudo privileges. You should not enable this if you use untrusted autocompletion scripts.

Note: This special kind of context-aware completion is only available for a small number of commands.

Key bindings

Zsh does not use readline, instead it uses its own and more powerful Zsh Line Editor (ZLE). It does not read /etc/inputrc or ~/.inputrc.

ZLE has an emacs mode and a vi mode. If one of the $VISUAL or $EDITOR environment variables contain the string vi then vi mode will be used; otherwise, it will default to emacs mode. Set the mode explicitly with bindkey -e or bindkey -v respectively for emacs mode or vi mode.

Add the following to your ~/.zshrc to set up key bindings using key sequences from terminfo(5):

~/.zshrc

# create a zkbd compatible hash;
# to add other keys to this hash, see: man 5 terminfo
typeset -g -A key

key[Home]="${terminfo[khome]}"
key[End]="${terminfo[kend]}"
key[Insert]="${terminfo[kich1]}"
key[Backspace]="${terminfo[kbs]}"
key[Delete]="${terminfo[kdch1]}"
key[Up]="${terminfo[kcuu1]}"
key[Down]="${terminfo[kcud1]}"
key[Left]="${terminfo[kcub1]}"
key[Right]="${terminfo[kcuf1]}"
key[PageUp]="${terminfo[kpp]}"
key[PageDown]="${terminfo[knp]}"
key[ShiftTab]="${terminfo[kcbt]}"

# setup key accordingly
[[ -n "${key[Home]}"      ]] && bindkey -- "${key[Home]}"      beginning-of-line
[[ -n "${key[End]}"       ]] && bindkey -- "${key[End]}"       end-of-line
[[ -n "${key[Insert]}"    ]] && bindkey -- "${key[Insert]}"    overwrite-mode
[[ -n "${key[Backspace]}" ]] && bindkey -- "${key[Backspace]}" backward-delete-char
[[ -n "${key[Delete]}"    ]] && bindkey -- "${key[Delete]}"    delete-char
[[ -n "${key[Up]}"        ]] && bindkey -- "${key[Up]}"        up-line-or-history
[[ -n "${key[Down]}"      ]] && bindkey -- "${key[Down]}"      down-line-or-history
[[ -n "${key[Left]}"      ]] && bindkey -- "${key[Left]}"      backward-char
[[ -n "${key[Right]}"     ]] && bindkey -- "${key[Right]}"     forward-char
[[ -n "${key[PageUp]}"    ]] && bindkey -- "${key[PageUp]}"    beginning-of-buffer-or-history
[[ -n "${key[PageDown]}"  ]] && bindkey -- "${key[PageDown]}"  end-of-buffer-or-history
[[ -n "${key[ShiftTab]}"  ]] && bindkey -- "${key[ShiftTab]}"  reverse-menu-complete

# Finally, make sure the terminal is in application mode, when zle is
# active. Only then are the values from $terminfo valid.
if (( ${+terminfo[smkx]} && ${+terminfo[rmkx]} )); then
	autoload -Uz add-zle-hook-widget
	function zle_application_mode_start {
		echoti smkx
	}
	function zle_application_mode_stop {
		echoti rmkx
	}
	add-zle-hook-widget -Uz zle-line-init zle_application_mode_start
	add-zle-hook-widget -Uz zle-line-finish zle_application_mode_stop
fi

See ZshWiki:Keybindings for more information.

History search

You need to set up #Key bindings to use this. To enable history search add these lines to .zshrc file:

~/.zshrc

autoload -Uz up-line-or-beginning-search down-line-or-beginning-search
zle -N up-line-or-beginning-search
zle -N down-line-or-beginning-search

[[ -n "${key[Up]}"   ]] && bindkey -- "${key[Up]}"   up-line-or-beginning-search
[[ -n "${key[Down]}" ]] && bindkey -- "${key[Down]}" down-line-or-beginning-search

By doing this, only the past commands matching the current line up to the current cursor position will be shown when Up or Down keys are pressed.

Prompts

Zsh supports:

left side prompts:
- PS1 (or PROMPT),
- PS2 (or PROMPT2),
- PS3 (or PROMPT3),
- PS4 (or PROMPT4).
right side prompts:
- RPS1 (or RPROMPT),
- RPS2 (or RPROMPT2).

See zshparam(1) § PARAMETERS USED BY THE SHELL for their explanation.

Prompt themes

There is a quick and easy way to set up a colored prompt in Zsh. Make sure that prompt theme system is set to autoload in .zshrc. This can be done by adding these lines to:

~/.zshrc

autoload -Uz promptinit
promptinit

Available prompt themes are listed by running the command:

$ prompt -l

For example, to use the walters theme, enter:

$ prompt walters

To preview all available themes, use this command:

$ prompt -p

Manually installing prompt themes

It is possible to install themes manually, without external configuration manager tools. For a local installation, first create a folder and add it to the fpath array, eg:

$ mkdir ~/.zprompts && fpath=( "$HOME/.zprompts" $fpath )

Now create a symbolic link of your theme file in this folder:

$ ln -s mytheme.zsh ~/.zprompts/prompt_mytheme_setup

If instead you wish to install a theme globally, do:

# ln -s mytheme.zsh /usr/share/zsh/functions/Prompts/prompt_mytheme_setup

Now you should be able to activate it using:

$ prompt mytheme

If everything works, you can edit your .zshrc accordingly.

Customized prompt

For users who are dissatisfied with the prompt themes mentioned above (or want to expand their usefulness), Zsh offers the possibility to build a custom prompt. Zsh supports a left- and right-sided prompt additional to the single, left-sided prompt that is common to all shells. Customize it by using PROMPT= with prompt escapes.

See zshmisc(1) § EXPANSION OF PROMPT SEQUENCES for a list of prompt variables and conditional substrings.

Colors

This article or section needs expansion.

Reason: Explain how to use 24-bit true color (e.g. %F{#a836c4}) and zsh/nearcolor module. (Discuss in Talk:Zsh)

Zsh sets colors differently than Bash. See zshmisc(1) § Visual effects for prompt escapes to set foreground color, background color and other visual effects.

Colors can be specified by numeric color code or by name. Most terminals support the following colors by name[1]:

Possible color values
`black` or `0`	`red` or `1`
`green` or `2`	`yellow` or `3`
`blue` or `4`	`magenta` or `5`
`cyan` or `6`	`white` or `7`

See xterm-256color chart for color codes supported by terminal emulators compatible with xterm 256 colors.

Note: Many terminal emulators display bold with a brighter color.

Tip: Prompt escapes can be tested with command print -P "prompt escapes", for example:

$ print -P '%B%F{red}co%F{green}lo%F{blue}rs%f%b'

Example

This is an example of a two-sided prompt:

PROMPT='%F{red}%n%f@%F{blue}%m%f %F{yellow}%1~%f %# '
RPROMPT='[%F{yellow}%?%f]'

And here is how it will be displayed:

username@host ~ %                                                         [0]

Sample .zshrc files

To get the same setup as the monthly ISO releases (which use Zsh by default), install grml-zsh-config. It includes the many tweaks and advanced optimizations from grml.
https://github.com/MrElendig/dotfiles-alice/blob/master/.zshrc - basic setup, with dynamic prompt and window title/hardinfo.
https://github.com/slashbeast/conf-mgmt/blob/master/roles/home_files/files/DOTzshrc - zshrc with multiple features, be sure to check out comments into it. Notable features: confirm function to ensure that user want to run poweroff, reboot or hibernate, support for GIT in prompt (done without vcsinfo), tab completion with menu, printing current executed command into window's title bar and more.

See dotfiles#User repositories for more.

Configuration Frameworks

Antigen — A plugin manager for zsh, inspired by oh-my-zsh and vundle.

https://github.com/zsh-users/antigen || antigen-git^AUR

Antibody — A performance-focused plugin manager similar to Antigen.

https://github.com/getantibody/antibody || antibody^AUR

oh-my-zsh — A popular, community-driven framework for managing your Zsh configuration. It comes bundled with a ton of helpful functions, helpers, plugins, themes.

https://github.com/robbyrussell/oh-my-zsh || oh-my-zsh-git^AUR

Prezto — A configuration framework for Zsh. It comes with modules, enriching the command line interface environment with sane defaults, aliases, functions, auto completion, and prompt themes.

https://github.com/sorin-ionescu/prezto || prezto-git^AUR

ZIM — A configuration framework with blazing speed and modular extensions. Zim is very easy to customize, and comes with a rich set of modules and features without compromising on speed or functionality.

https://github.com/zimfw/zimfw || zsh-zim-git^AUR

Tips and tricks

Autostart X at login

See xinit#Autostart X at login.

The "command not found" hook

pkgfile includes a "command not found" hook that will automatically search the official repositories, when entering an unrecognized command.

You need to source the hook to enable it, for example:

~/.zshrc

source /usr/share/doc/pkgfile/command-not-found.zsh

Note: The pkgfile database may need to be updated before this will work. See pkgfile#Installation for details.

The ttyctl command

[2] describes the ttyctl command in Zsh. This may be used to "freeze/unfreeze" the terminal. Many programs change the terminal state, and often do not restore terminal settings on exiting abnormally. To avoid the need to manually reset the terminal, use the following:

~/.zshrc

ttyctl -f

Remembering recent directories

Dirstack

Zsh can be configured to remember the DIRSTACKSIZE last visited folders. This can then be used to cd them very quickly. You need to add some lines to your configuration file:

~/.zshrc

DIRSTACKFILE="$HOME/.cache/zsh/dirs"
if [[ -f $DIRSTACKFILE ]] && [[ $#dirstack -eq 0 ]]; then
  dirstack=( ${(f)"$(< $DIRSTACKFILE)"} )
  [[ -d $dirstack[1] ]] && cd $dirstack[1]
fi
chpwd() {
  print -l $PWD ${(u)dirstack} >$DIRSTACKFILE
}

DIRSTACKSIZE=20

setopt AUTO_PUSHD PUSHD_SILENT PUSHD_TO_HOME

## Remove duplicate entries
setopt PUSHD_IGNORE_DUPS

## This reverts the +/- operators.
setopt PUSHD_MINUS

Now use

$ dirs -v

to print the dirstack. Use cd -<NUM> to go back to a visited folder. Use autocompletion after the dash. This proves very handy if using the autocompletion menu.

Note: This will not work if you have more than one zsh session open, and attempt to cd, due to a conflict in both sessions writing to the same file.

cdr

cdr allows you to change the working directory to a previous working directory from a list maintained automatically. It stores all entries in files that are maintained across sessions and (by default) between terminal emulators in the current session.

See zshcontrib(1) § REMEMBERING RECENT DIRECTORIES.

Help command

Zsh help command is called run-help. Unlike bash, zsh does not enable it by default. To use help in zsh, add following to your zshrc:

autoload -Uz run-help
unalias run-help
alias help=run-help

run-help will invoke man for external commands. Default keyboard shortcut is Alt+h or Esc+h.

run-help has assistant functions, they need to be enabled separately:

autoload -Uz run-help-git
autoload -Uz run-help-ip
autoload -Uz run-help-openssl
autoload -Uz run-help-p4
autoload -Uz run-help-sudo
autoload -Uz run-help-svk
autoload -Uz run-help-svn

For example run-help git commit command will now open the man page git-commit(1) instead of git(1).

Fish-like syntax highlighting

Fish provides a very powerful shell syntax highlighting. To use this in zsh, you can install zsh-syntax-highlighting from offical repository and add following to your zshrc:

source /usr/share/zsh/plugins/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh

Persistent rehash

Typically, compinit will not automatically find new executables in the $PATH. For example, after you install a new package, the files in /usr/bin/ would not be immediately or automatically included in the completion. Thus, to have these new executables included, one would run:

$ rehash

This 'rehash' can be set to happen automatically.[3] Simply include the following in your zshrc:

~/.zshrc

zstyle ':completion:*' rehash true

On-demand rehash

As above, however pacman can be configured with hooks to automatically request a rehash, which does not incur the performance penalty of constant rehashing as above. To enable this, create the /etc/pacman.d/hooks directory, and a /var/cache/pacman directory, then create a hook file:

/etc/pacman.d/hooks/zsh.hook

[Trigger]
Operation = Install
Operation = Upgrade
Operation = Remove
Type = Package
Target = *
[Action]
Depends = zsh
When = PostTransaction
Exec = /usr/bin/env touch /var/cache/zsh/pacman

This keeps the modification date of the file /var/cache/zsh/pacman consistent with the last time a package was installed, upgraded or removed. Then, zsh must be coaxed into rehashing its own command cache when it goes out of date, by adding to your ~/.zshrc:

~/.zshrc

zshcache_time="$(date +%s%N)"

autoload -Uz add-zsh-hook

rehash_precmd() {
  if [[ -a /var/cache/zsh/pacman ]]; then
    local paccache_time="$(date -r /var/cache/zsh/pacman +%s%N)"
    if (( zsh_cache_time < paccache_time )); then
      rehash
      zshcache_time="$paccache_time"
    fi
  fi
}

add-zsh-hook -Uz precmd rehash_precmd

If the precmd hook is triggered before /var/cache/zsh/pacman is updated, completion may not work until a new prompt is initiated. Running an empty command, e.g. pressing enter, should be sufficient.

Bind key to ncurses application

Bind a ncurses application to a keystroke, but it will not accept interaction. Use BUFFER variable to make it work. The following example lets users open ncmpcpp using Alt+\:

~/.zshrc

ncmpcppShow() { BUFFER="ncmpcpp"; zle accept-line; }
zle -N ncmpcppShow
bindkey '^[\' ncmpcppShow

An alternate method, that will keep everything you entered in the line before calling application:

~/.zshrc

ncmpcppShow() { ncmpcpp <$TTY; zle redisplay; }
zle -N ncmpcppShow
bindkey '^[\' ncmpcppShow

File manager key binds

Key binds like those used in graphic file managers may come handy. The first comes back in directory history (Alt+Left), the second let the user go to the parent directory (Alt+Up). They also display the directory content.

~/.zshrc

cdUndoKey() {
  popd
  zle       reset-prompt
  echo
  ls
  zle       reset-prompt
}

cdParentKey() {
  pushd ..
  zle      reset-prompt
  echo
  ls
  zle       reset-prompt
}

zle -N                 cdParentKey
zle -N                 cdUndoKey
bindkey '^[[1;3A'      cdParentKey
bindkey '^[[1;3D'      cdUndoKey

xterm title

If your terminal emulator supports it you can set its title from Zsh. This allows dynamically changing the the title to display relevant information about the shell state, for example showing the user name and current directory or the currently executing command.

xterm title is set with xterm escape sequences. For example:

$ print -n '\e]2;My xterm title\a'

will set the title to

My xterm title

An simple way to have a dynamic title is to set the title in a hook functions precmd and preexec. See zshmisc(1) § Hook Functions.

By using print -P you can take advantage of prompt escapes.

Tip:

Title printing can be split up in multiple commands as long as they are sequential.
GNU Screen sends the xterm title to the hardstatus (%h). If you want to use Screen's string escapes (e.g. for colors) you should set the hardstatus with the \e_\e\\ escape sequence. Otherwise, if string escapes are used in \e]2;\a, the terminal emulator will get a garbled title due to it being incapable of interpreting them.

Note:

Do not use -P option of print when printing variables to prevent them from being parsed as prompt escapes.
Use q parameter expansion flag when printing variables to prevent them from being parsed as escape sequences.

~/.zshrc

autoload -Uz add-zsh-hook

function xterm_title_precmd () {
	print -Pn '\e]2;%n@%m %1~\a'
	[[ "$TERM" == 'screen'* ]] && print -Pn '\e_\005{r}%n\005{-}@\005{b}%m\005{-} \005{y}%1~\005{-}\e\\'
}

function xterm_title_preexec () {
	print -Pn '\e]2;%n@%m %1~ %# ' && print -n "${(q)1}\a"
	[[ "$TERM" == 'screen'* ]] && { print -Pn '\e_\005{r}%n\005{-}@\005{b}%m\005{-} \005{y}%1~\005{-} %# ' && print -n "${(q)1}\e\\"; }
}

if [[ "$TERM" == (screen*|xterm*|rxvt*) ]]; then
	add-zsh-hook -Uz precmd xterm_title_precmd
	add-zsh-hook -Uz preexec xterm_title_preexec
fi

Terminal emulator tab title

Some terminal emulators and multiplexers support setting the title of the tab. The escape sequences depend on the terminal:

Terminal	Escape sequences	Description
GNU Screen	`\ekInsert title here\e\\`	Screen's window title (`%t`).
Konsole	`\e]30;Insert title here\a`	Konsole's tab title.

Uninstallation

Change the default shell before removing the zsh package.

Warning: Failure to follow the below procedure may result in users no longer having access to a working shell.

Run following command:

$ chsh -s /bin/bash user

Use it for every user with zsh set as their login shell (including root if needed). When completed, the zsh package can be removed.

Alternatively, change the default shell back to Bash by editing /etc/passwd as root.

Warning: It is strongly recommended to use vipw(8) when editing /etc/passwd as it helps prevent invalid entries and/or syntax errors.

For example, change the following:

username:x:1000:1000:Full Name,,,:/home/username:/bin/zsh

To this:

username:x:1000:1000:Full Name,,,:/home/username:/bin/bash

@@ Line 215: / Line 215: @@
 Zsh supports:
-* left side prompts: {{ic|PS1}} (or {{ic|PROMPT}}), {{ic|PS2}}, {{ic|PS3}}, {{ic|PS4}}.
+* left side prompts:
-* right side prompts: {{ic|RPS1}} (or {{ic|RPROMPT}}), {{ic|RPS2}} (or {{ic|RPROMPT2}}).
+** {{ic|PS1}} (or {{ic|PROMPT}}),
+** {{ic|PS2}} (or {{ic|PROMPT2}}),
+** {{ic|PS3}} (or {{ic|PROMPT3}}),
+** {{ic|PS4}} (or {{ic|PROMPT4}}).
+* right side prompts:
+** {{ic|RPS1}} (or {{ic|RPROMPT}}),
+**  {{ic|RPS2}} (or {{ic|RPROMPT2}}).
 See {{man|1|zshparam|PARAMETERS USED BY THE SHELL}} for their explanation.

Revision as of 08:56, 9 April 2019

Installation

Initial configuration

Making Zsh your default shell

Startup/Shutdown files

Configure Zsh

Simple .zshrc

Configuring $PATH

Command completion

Key bindings

History search

Prompts

Prompt themes

Manually installing prompt themes

Customized prompt

Colors

Example

Sample .zshrc files

Configuration Frameworks

Tips and tricks

Autostart X at login

The "command not found" hook

The ttyctl command

Remembering recent directories

Dirstack

cdr

Help command

Fish-like syntax highlighting

Persistent rehash

On-demand rehash

Bind key to ncurses application

File manager key binds

xterm title

Terminal emulator tab title

Uninstallation

See also