Liquid prompt -- A useful adaptive Bash prompt

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

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.

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 branch "myb":

1r [user@server:~/liquidprompt] myb ±

A liquid prompt displaying everything may look like this:

25% 12.5 1s/1r [user@server:~/liquidprompt] master(3) 125 ±

It displays:

• the average of the batteries remaining power, if it is under a given threshold, with a colormap too;
• 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 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;
• the current user, in bold yellow if it is root;
• the current host, if you are connected via an SSH or telnet connection, with different colors for each case;
• the current directory in bold;
• the name of the current branch if you are in a version control repository (git, mercurial or subversion), 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 pending commits, if any;
• the error code of the last command, if it has failed in some way;
• a smart mark: ± for VCS directories, $ for simple user, a red # for root.

USAGE

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

source liquidprompt.bash

PUT THE PROMPT IN A DIFFERENT ORDER

Most of the display is prepared in the __set_bash_prompt function, apart from features that needs several colors (such as the load colormap). You can sort what you want to see by editing the PS1 variable.

KNOWN LIMITATIONS AND BUGS

• Does not display the number of commits to be pushed in Mercurial repositories.
• Subversion repository cannot display commits to be pushed, this is a limitation of the Subversion versionning model.