Liquid prompt -- A useful adaptive prompt for Bash & Zsh

Liquid prompt is a smart prompt for the "Bourne-Again" Unix shell (bash) and for Zsh.

The basic idea of the liquid prompt is to nicely display useful informations on the shell prompt, only when they are needed. It adds carefuly chosen colors to draw your attention on what differs from the normal context. Thus, you will notice what changes, when it changes, because you do not become accommodated to informations that are always displayed in the same way.

You can use it with either bash and zsh.

FEATURES

If there is nothing special in the current context, the liquid prompt is close to a default prompt:

[user:~] $

If you have ran one command in background that is still running and that you are in a git repository on a server, at branch "myb":

1r [user@server:~/liquidprompt] myb ±

A liquid prompt displaying everything may look like this:

⌁24% ⌂42% 3d/2&/1z [user@server:~/ … /code/liquidprompt]↥ master(+10/-5,3)* 125 ±

It displays:

• a green ⌁ if the battery is charging and above a given threshold, a yellow ⌁ if the battery is charging and under threshold, a red ⌁ if the battery is discharging but above threshold;
• the average of the batteries remaining power, if it is under the given threshold, with a colormap, going more and more red with decreasing power;
• the average of the processors load, if it is over a given limit, with a colormap that became more and more noticeable with increasing load;
• the number of detached sessions (screen), if there is any;
• the number of attached sleeping jobs (when you interrupt a command with Ctrl-Z and bring it back with fg), if there is any;
• the number of attached running jobs (commands started with a &), if there is any;
• a pair of square brackets, in blue if your current shell is running in a terminal multiplexer (screen or tmux);
• the current user, in bold yellow if it is root, in light white if it is not the same as the login user;
• a blue @ if the connection has X11 support;
• the current host, if you are connected via an SSH or telnet connection, with different colors for each case;
• a green colon if the user has write permissions on the current directory, a red one if he has not;
• the current directory in bold, shortened if it takes too much space, while preserving the first two directories;
• the current Python virtual environment, if any;
• an up arrow if an HTTP proxy is in use;
• the name of the current branch if you are in a version control repository (git, mercurial, subversion or fossil), in green if everything is up to date, in red if there is changes, in yellow if there is pending commits to push;
• the number of added/deleted lines (git) or files (fossil), if changes have been made and the number of pending commits, if any;
• a yellow plus if there is stashed modifications;
• a red star if there is some untracked files in the repository;
• the error code of the last command, if it has failed in some way;
• a smart mark: ± for git directories, ☿ for mercurial, ‡ for svn, ⌘ for fossil, $ for simple user, a red # for root;
• if you ask for, the liquidprompt will be replicated in your terminal window's title (without the colors);
• you can easily add a prefix tag to your prompt, by invoking prompt_tag MYTAG.

You can temporarily deactivate the liquid prompt and come back to your previous one by typing prompt_off. Use prompt_on to bring it back. You can deactivate any prompt and use a single mark sign ($ for user and # for root) with the prompt_OFF command.

INSTALL

Include the file in your bash configuration, for example in your .bashrc:

source liquidprompt

Copy the liquidpromptrc-dist file in your home directory as ~/.config/liquidpromptrc or ~/.liquidpromptrc and edit it according to your preferences. If you skip this step, the default behaviour will be used.

Note that you should not overwrite the PROMPT_COMMAND variable, or else the prompt will not be available.

DEPENDENCIES

Apart from obvious ones, some features depends on specific commands. If you do not install them, the corresponding feature will not be available, but you will see no error.

• battery status need acpi,
• detached sessions is looking for screen.
• VCS support features needs… git, hg or svn, but you knew it.

For other features, the script uses commands that should be available on a large variety of unixes: tput, grep, awk, sed, ps, who.

FEATURES CONFIGURATION

You can configure some variables in the ~/.liquidpromptrc file:

• LP_BATTERY_THRESHOLD, the maximal value under which the battery level is displayed
• LP_LOAD_THRESHOLD, the minimal value after which the load average is displayed
• LP_PATH_LENGTH, the maximum percentage of the screen width used to display the path
• LP_PATH_KEEP, how many directories to keep at the beginning of a shortened path
• LP_HOSTNAME_ALWAYS, choose between always displaying the hostname or showing it only when connected with a remote shell
• LP_USER_ALWAYS, choose between always displaying the user or showing it only when he is different from the logged one

You can also force some features to be disabled, to save some time in the prompt building:

• LP_ENABLE_PERM, if you want to detect if the directory is writable
• LP_ENABLE_SHORTEN_PATH, if you to shorten the path display
• LP_ENABLE_PROXY, if you want to detect if a proxy is used
• LP_ENABLE_JOBS, if you want to have jobs informations
• LP_ENABLE_LOAD, if you want to have load informations
• LP_ENABLE_BATT, if you want to have battery informations
• LP_ENABLE_GIT, if you want to have git informations
• LP_ENABLE_SVN, if you want to have subversion informations
• LP_ENABLE_HG, if you want to have mercurial informations
• LP_ENABLE_FOSSIL, if you want to have fossil informations
• LP_ENABLE_VCS_ROOT, if you want to show VCS informations with root account
• LP_ENABLE_TITLE, if you want to use the prompt as your terminal window's title
• LP_ENABLE_SCREEN_TITLE, if you want to use the prompt as your screen window's title

Note that if required commands are not installed, enabling the corresponding feature will have no effect. Note also that all the LP_ENABLE_… variables override the templates, i.e. if you use $LP_BATT in your template and you set LP_ENABLE_BATT=0 in your config file, you will not have the battery informations.

If you are using bash and want to use the PROMPT_DIRTRIM built-in functionality to shorten but still have liquidprompt calculating the number of directories to keep in the path, precise a value for PROMPT_DIRTRIM before sourcing liquidprompt and liquidprompt will override this value with one fitting the width of your terminal.

CUSTOMIZING THE PROMPT

ADD A PS1 PREFIX

You can prefix the LP_PS1 variable with anything you want using the LP_PS1_PREFIX. The following example activate a custom window's title:

LP_PS1_PREFIX="\[\e]0;\u@\h: \w\a\]"

Note: the prompt_tag function is convenient way to add a prefix. You can thus add a keyword to your different terminals:

[:~/code/liquidprompt] develop ± prompt_tag mycode
mycode [:~/code/liquidprompt] develop ±

PUT THE PROMPT IN A DIFFERENT ORDER

You can sort what you want to see by sourcing your favorite template file (*.ps1) in the configuration file.

Those scripts basically export the LP_PS1 variable, by appending features and theme colors.

Available features:

• LP_BATT battery
• LP_LOAD load
• LP_JOBS screen sessions/running jobs/suspended jobs
• LP_USER user
• LP_HOST hostname
• LP_PERM a colon ":"
• LP_PWD current working directory
• LP_PROXY HTTP proxy
• LP_VCS informations concerning the current working repository
• LP_ERR last error code
• LP_MARK prompt mark
• LP_TITLE the prompt as a window's title escaped sequence

For example, if you just want to have a liquidprompt displaying the user and the host, with a normal full path in blue and only the git support:

export LP_PS1=`echo -ne "[\${LP_USER}\${LP_HOST}:\${BLUE}\$(pwd)\${NO_COL}] \${LP_GIT} \\\$ "`

Note that you need to properly escape dollars in a string that wil be interpreted by bash at each prompt.

To erase your new formatting, just bring the LP_PS1 to a null string:

 export LP_PS1=""

THEMES

You can change the colors and special characters of some part of the liquid prompt by sourcing your favorite theme file (*.theme) in the configuration file.

COLORS

Available colors are: BOLD, BLACK, BOLD_GRAY, WHITE, BOLD_WHITE, GREEN, BOLD_GREEN, YELLOW, BOLD_YELLOW, BLUE, BOLD_BLUE, PINK, CYAN, BOLD_CYAN RED, BOLD_RED, WARN_RED, CRIT_RED, DANGER_RED, NO_COL. Set to a null string "" if you do not want color.

• Current working directory
  • LP_COLOR_PATH as normal user
  • LP_COLOR_PATH_ROOT as root
• Color of the proxy mark
  • LP_COLOR_PROXY
• Jobs count
  • LP_COLOR_JOB_D Detached (aka screen sessions)
  • LP_COLOR_JOB_R Running (xterm &)
  • LP_COLOR_JOB_Z Sleeping (Ctrl-Z)
  • LP_COLOR_IN_MULTIPLEXER currently running in a terminal multiplexer
• Last error code
  • LP_COLOR_ERR
• Prompt mark
  • LP_COLOR_MARK as user
  • LP_COLOR_MARK_ROOT as root
• Current user
  • LP_COLOR_USER_LOGGED user who logged in
  • LP_COLOR_USER_ALT user but not the one who logged in
  • LP_COLOR_USER_ROOT root
• Hostname
  • LP_COLOR_HOST local host
  • LP_COLOR_SSH connected via SSH
  • LP_COLOR_TELNET connected via telnet
  • LP_COLOR_X11_ON connected with X11 support
  • LP_COLOR_X11_OFF connected without X11 support
• Separation mark (aka permiison in the working dir)
  • LP_COLOR_WRITE have write permission
  • LP_COLOR_NOWRITE do not have write permission
• VCS
  • LP_COLOR_UP repository is up to date / a push have been made
  • LP_COLOR_COMMITS some commits have not been pushed
  • LP_COLOR_CHANGES there is some changes to commit
  • LP_COLOR_DIFF number of lines or files impacted by current changes
• Battery
  • LP_COLOR_CHARGING_ABOVE charging and above threshold
  • LP_COLOR_CHARGING_UNDER charging but under threshold
  • LP_COLOR_DISCHARGING_ABOVE discharging but above threshold
  • LP_COLOR_DISCHARGING_UNDER discharging and under threshold

CHARACTERS

Special characters:

• LP_MARK_BATTERY (default: "⌁") in front of the battery charge
• LP_MARK_ADAPTER (default: "⏚") displayed when plugged
• LP_MARK_LOAD (default: "⌂") in front of the load
• LP_MARK_PROXY (default: "↥") indicate a proxy in use
• LP_MARK_HG (default: "☿") prompt mark in hg repositories
• LP_MARK_SVN (default: "‡") prompt mark in svn repositories
• LP_MARK_GIT (default: "±") prompt mark in git repositories
• LP_MARK_FOSSIL (default: "⌘") prompt mark in fossil repositories
• LP_MARK_UNTRACKED (default: "*") if git has untracked files
• LP_MARK_STASH (default: "+") if git has stashed modifications
• LP_MARK_BRACKET_OPEN (default: "[") marks around the main part of the prompt
• LP_MARK_BRACKET_CLOSE (default: "]") marks around the main part of the prompt
• LP_TITLE_OPEN (default: "\e]0;") escape character opening a window's title
• LP_TITLE_CLOSE (default: "\a") escape character closing a window's title
• LP_SCREEN_TITLE_OPEN (default: "\033k") escape character opening screen window's title
• LP_SCREEN_TITLE_CLOSE (default: "\033\134") escape character closing screen window's title

KNOWN LIMITATIONS AND BUGS

Liquid prompt is distributed under the GNU Affero General Public License version 3.

• detached sessions only looks for screen, a tmux support would be nice…
• Does not display the number of commits to be pushed in Mercurial repositories.
• Browsing into very large subversion repositories may dramatically slow down the display of the liquid prompt.
• Subversion repository cannot display commits to be pushed, this is a limitation of the Subversion versionning model.
• The proxy detection only uses the $http_proxy environment variable.
• The window's title escape sequence may not work properly on some terminals (like xterm-256)