# 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

### 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

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'll 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.

`$ZDOTDIR/.zprofile`
  Used for executing user's commands at start, will be sourced when starting as a login shell.
`/etc/zsh/zshrc`
  Used for setting interactive shell configuration and executing commands, will be sourced when starting as a interactive shell.
`$ZDOTDIR/.zshrc`
  Used for setting user's interactive shell configuration and executing commands, will be sourced when starting as a 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)
- `/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 other, it'll break the integrality 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

Normally, the path should be set in `~/.zshenv`, but Arch Linux sources `/etc/profile` after sourcing `~/.zshenv`.

To prevent your $PATH being overwritten, set it in `~/.zprofile`.

    ~/.zprofile

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

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

### 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 need to prevent ssh from hashing hosts names in `~/.ssh/known_hosts`.

Warning: This makes the computer vulnerable to "Island-hopping" attacks. In that intention, comment the following line or set the value to `no`:

    /etc/ssh/ssh_config

    #HashKnownHosts yes

And move `~/.ssh/known_hosts` somewhere else so that ssh creates a new one with un-hashed hostnames (previously known hosts will thus be lost). For more information, see the SSH readme for hashed-hosts.

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

### Autostart X at login

See Xinitrc#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

### The ttyctl command

[1] 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

### Key bindings

Zsh does not use readline, instead it uses its own and more powerful 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.

See also zshwiki: bindkeys.

#### Bind key to ncurses application

Bind a ncurses application to a keystoke, 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

#### Alternate way to bind ncurses application

This method 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      > /dev/null
      zle       reset-prompt
      echo
      ls
      echo
    }

    cdParentKey() {
      pushd .. > /dev/null
      zle      reset-prompt
      echo
      ls
      echo
    }

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

### History search

Add these lines to .zshrc

    ~/.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

Doing this, only past commands matching the current line up to the current cursor position will be shown.

### Prompts

#### 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

#### Customized prompt

For users who are dissatisfied with the prompts 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 Prompt Expansion for a list of prompt variables and conditional substrings, or take a look at the zshmisc(1) manpage.

##### Colors

Zsh sets colors differently than Bash. Add `autoload -Uz colors && colors` before `PROMPT=` in `.zshrc` to use them. Usually you will want to put these inside `%{ [...] %}` so the cursor does not move.

Command | Description
--- | ---
`$fg[color]` | will set the text color (red, green, blue, etc. - defaults to whatever format set prior to text)
`%F{color} [...] %f` | effectively the same as the previous, but with less typing. Can also prefix F with a number instead.
`$fg_no_bold[color]` | will set text to non-bold and set the text color
`$fg_bold[color]` | will set the text to bold and set the text color
`$reset_color` | will reset the text color to the default color. Does not reset bold. use `%b` to reset bold. Saves typing if it's just `%f` though.
`%K{color} [...] %k` | will set the background color. Same color as non-bold text color. Prefixing with any single-digit number makes the bg black.
`%S [...] %s` | Standout mode, switches the text and background colors. Useful for Powerline-like prompts, especially if you switch between light/dark backgrounds.

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`

Note: Bold text does not necessarily use the same colors as normal text. For example, `$fg['yellow']` looks brown or a very dark yellow, while `$fg_bold['yellow']` looks like bright or regular yellow.

##### Example

This is an example of a two-sided prompt:

    PROMPT="%{$fg[red]%}%n%{$reset_color%}@%{$fg[blue]%}%m %{$fg_no_bold[yellow]%}%1~ %{$reset_color%}%# "
    RPROMPT="[%{$fg_no_bold[yellow]%}%?%{$reset_color%}]"

And here's how it will be displayed:

    username@host ~ %                                                         [0]

### 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. To use cdr add the following lines to shell configuration:

    .zshrc

    autoload -Uz chpwd_recent_dirs cdr add-zsh-hook
    add-zsh-hook chpwd chpwd_recent_dirs

Recent directories list by default is stored in `${ZDOTDIR:-$HOME}/.chpwd-recent-dirs`, to change it use `zstyle`:

    zstyle ':chpwd:*' recent-dirs-file "${XDG_CACHE_HOME:-$HOME/.cache}/zsh/chpwd-recent-dirs"

Every time you change directory interactively, no matter which command you use, the directory to which you change will be remembered in most-recent-first order.

To print the list of recent directories use:

    $ cdr -l

Use `cdr <NUM>` to go back to a visited folder. Completion for the argument to cdr is available if compinit has been run; menu selection is recommended.

### Help command

Unlike bash, zsh does not enable a built in `help` command. To use `help` in zsh, add following to your `zshrc`:

    autoload -Uz run-help
    autoload -Uz run-help-git
    autoload -Uz run-help-svn
    autoload -Uz run-help-svk
    unalias run-help
    alias help=run-help

### 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

### Sample .zshrc files

- A package in offical repository named grml-zsh-config comes from https://grml.org/zsh and provides a zshrc file that includes many tweaks for Zshell. This is the default configuration for the monthly ISO releases.
- https://github.com/MrElendig/dotfiles-alice/blob/master/.zshrc - basic setup, with dynamic prompt and window title/hardinfo.
- https://github.com/slashbeast/things/blob/master/configs/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#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-gitAUR

- 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-gitAUR

  Note: For themes to work you may need to set `setopt NO_GLOBAL_RCS` in the `~/.zshenv` file, otherwise changes to some variables (such as `$PROMPT`) may be overwritten.

- 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-gitAUR

### 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 exectuables included, one would run:

    $ rehash

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

    ~/.zshrc

    zstyle ':completion:*' rehash true

Note: This hack has been found in a PR for Oh My Zsh [2]

## 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` 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

## See also

- A User's Guide to ZSH
- The Z Shell Manual (different format available here)
- Zsh FAQ
- zsh-lovers(1) (available as zsh-lovers package)
- Zsh Wiki
- Gentoo: Zsh/Guide
- Bash2Zsh Reference Card

Category:

- Command shells