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

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;
* the current user, in bold yellow if it is root, in light white if it is not
the same as the login user;
* 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;
* 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 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 added/deleted lines, if changes have been made and 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 git directories, ☿ for mercurial, ‡ for svn, $ for simple
user, a red # for root.

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.


## 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`.


## PUT THE PROMPT IN A DIFFERENT ORDER

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_REVERSE`, choose between reverse colors (black on white) or normal theme
(white on black)
* `LP_HOSTNAME_ALWAYS`, choose between always displaying the hostname or showing
it only when connected with a remote shell

You can sort what you want to see by exporting the `LP_PS1` variable, using the
variables you will found in the `_lp_set_bash_prompt` function.

For example, if you just want to have a liquidprompt displaying the user and the
host, with a normal 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=""


## COLOR THEMES

You can change the colors of some part of the liquid prompt by changing the
following parameters in the config file.

Available colors are:
BOLD, BLACK, BOLD_GRAY, WHITE, BOLD_WHITE, RED, BOLD_RED, WARN_RED, CRIT_RED,
GREEN, BOLD_GREEN, YELLOW, BOLD_YELLOW, BLUE, BOLD_BLUE, PINK, CYAN, BOLD_CYAN.
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)
* 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
* Separation mark (aka permiison in the working dir)
    * `LP_COLOR_WRITE` have write permission
    * `LP_COLOR_NOWRITE` do not have write permission


## KNOWN LIMITATIONS AND BUGS

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

* Cannot easily change the colors of features having different state colors
(like the colormap of the load or the colors of the branch name).
* 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.