The original version of this article was first published on IBM
developerWorks, and is property of Westtech Information Services. This
document is an updated version of the original article, and contains
various improvements made by the Gentoo Linux Documentation team.
This document is not actively maintained.
Enhancing the system prompt
As Linux/UNIX people, we spend a lot of time working in the shell, and in many
cases, this is what we have staring back at us:
Code Listing 1.1: The normal user prompt
If you happen to be root, you're entitled to the "prestige" version of this
Code Listing 1.2: The root prompt
These prompts are not exactly pretty. It's no wonder that several Linux
distributions have upgraded their default prompts that add color and additional
information to boot. However, even if you happen to have a modern distribution
that comes with a nice, colorful prompt, it may not be perfect. Maybe you'd
like to add or change some colors, or add (or remove) information from the
prompt itself. It isn't hard to design your own colorized, tricked-out prompt
Under bash, you can set your prompt by changing the value of the PS1
environment variable, as follows:
Code Listing 1.3: Altering the environment variable
$ export PS1="> "
Changes take effect immediately, and can be made permanent by placing the
export definition in your ~/.bashrc file. PS1 can
contain any amount of plain text that you'd like:
Code Listing 1.4: A custom prompt
$ export PS1="This is my super prompt > "
This is my super prompt >
While this is, um, interesting, it's not exactly useful to have a prompt that
contains lots of static text. Most custom prompts contain information like the
current username, working directory, or hostname. These tidbits of information
can help you to navigate in your shell universe. For example, the following
prompt will display your username and hostname:
Code Listing 1.5: A more useful prompt
$ export PS1="\u@\H > "
This prompt is especially handy for people who log in to various machines under
various differently-named accounts, since it acts as a reminder of what machine
you're actually on and what privileges you currently have.
In the above example, we told bash to insert the username and hostname into the
prompt by using special backslash-escaped character sequences that bash
replaces with specific values when they appear in the PS1 variable. We
used the sequences \u (for username) and \H (for the first part
of the hostname). Here's a complete list of all special sequences that bash
recognizes (you can find this list in the bash man page, in the "PROMPTING"
||The ASCII bell character (you can also type \007)
||Date in "Wed Sep 06" format
||ASCII escape character (you can also type \033)
||First part of hostname (such as "mybox")
||Full hostname (such as "mybox.mydomain.com")
The number of processes you've suspended in this shell by hitting ^Z
||The name of the shell's terminal device (such as "ttyp4")
||The name of the shell executable (such as "bash")
||Time in 24-hour format (such as "23:01:01")
||Time in 12-hour format (such as "11:01:01")
||Time in 12-hour format with am/pm
||Version of bash (such as 2.04)
||Bash version, including patchlevel
||Current working directory (such as /home/drobbins)
||The "basename" of the current working directory (such as "drobbins")
||Current command's position in the history buffer
Command number (this will count up at each prompt, as long as you type
If you are not root, inserts a $; if you are root, you get a
#. If you delimit your string with ' instead of ", you
should use a single backslash instead.
Inserts an ASCII character based on three-digit number xxx (replace unused
digits with zeros, such as \007)
This sequence should appear before a sequence of characters that don't move
the cursor (like color escape sequences). This allows bash to calculate
word wrapping correctly.
This sequence should appear after a sequence of non-printing characters.
So, there you have all of bash's special backslashed escape sequences. Play
around with them for a bit to get a feel for how they work. After you've done a
little testing, it's time to add some color.
Adding color is quite easy; the first step is to design a prompt without color.
Then, all we need to do is add special escape sequences that'll be recognized
by the terminal (rather than bash) and cause it to display certain parts of the
text in color. Standard Linux terminals and X terminals allow you to set the
foreground (text) color and the background color, and also enable "bold"
characters if so desired. We get eight colors to choose from.
Colors are selected by adding special sequences to PS1 -- basically
sandwiching numeric values between an \e[ (escape open-bracket) and an
m. If we specify more than one numeric code, we separate each code with
a semicolon. Here's an example color code:
Code Listing 1.6: Adding color
When we specify a zero as a numeric code, it tells the terminal to reset
foreground, background, and boldness settings to their default values. You'll
want to use this code at the end of your prompt, so that the text that you type
in is not colorized. Now, let's take a look at the color codes. Check out this
Figure 1.1: Color chart
To use this chart, find the color you'd like to use, and find the corresponding
foreground (30-37) and background (40-47) numbers. For example, if you like
green on a normal black background, the numbers are 32 and 40. Then, take your
prompt definition and add the appropriate color codes. This:
Code Listing 1.7: A basic custom prompt
$ export PS1="\w> "
Code Listing 1.8: The colorized prompt
$ export PS1="\e[32;40m\w> "
So far, so good, but it's not perfect yet. After bash prints the working
directory, we need to set the color back to normal with an \e[0m
Code Listing 1.9: A better colorized prompt
$ export PS1="\e[32;40m\w> \e[0m"
This definition will give you a nice, green prompt, but we still need to add a
few finishing touches. We don't need to include the background color setting of
40, since that sets the background to black which is the default color anyway.
Also, the green color is quite dim; we can fix this by adding a 1 color
code, which enables brighter, bold text. In addition to this change, we need to
surround all non-printing characters with special bash escape sequences,
\[ and \]. These sequences will tell bash that the enclosed
characters don't take up any space on the line, which will allow word-wrapping
to continue to work properly. Without them, you'll end up with a nice-looking
prompt that will mess up the screen if you happen to type in a command that
approaches the extreme right of the terminal. Here's our final prompt:
Code Listing 1.10: A nice colorful prompt
$ export PS1="\[\e[32;1m\]\w> \[\e[0m\]"
Don't be afraid to use several colors in the same prompt, like so:
Code Listing 1.11: Much more colorful
$ export PS1="\[\e[36;1m\]\u@\[\e[32;1m\]\H> \[\e[0m\]"
I've shown you how to add information and color to your prompt, but you can do
even more. It's possible to add special codes to your prompt that will cause
the title bar of your X terminal (such as rxvt or aterm) to be dynamically
updated. All you need to do is add the following sequence to your PS1
Code Listing 1.12: Updating the xterm title bar
Simply replace the substring titlebar with the text that you'd like to
have appear in your xterm's title bar, and you're all set! You don't need to
use static text; you can also insert bash escape sequences into your titlebar.
Check out this example, which places the username, hostname, and current
working directory in the titlebar, as well as defining a short, bright green
Code Listing 1.13: An extremely useful xterm
$ export PS1="\[\e]2;\u@\H \w\a\e[32;1m\]>\[\e[0m\] "
This is the particular prompt that I'm using in the color chart screenshot,
above. I love this prompt, because it puts all the information in the title bar
rather than in the terminal where it limits how much can fit on a line. By the
way, make sure you surround your titlebar sequence with \[ and
\], since as far as the terminal is concerned, this sequence is
non-printing. The problem with putting lots of information in the title bar is
that you will not be able to see info if you are using a non-graphical
terminal, such as the system console. To fix this, you may want to add
something like this to your ~/.bashrc:
Code Listing 1.14: Adding usefulness to xterms and system consoles
if [ "$TERM" = "linux" ]
export PS1="\[\e[32;1m\]\u@\H > \[\e[0m\]"
export PS1="\[\e]2;\u@\H \w\a\e[32;1m\]>\[\e[0m\] "
This bash conditional statement will dynamically set your prompt based on your
current terminal settings. For consistency, you'll want to configure your
~/.bash_profile so that it sources your ~/.bashrc on
startup. Make sure the following line is in your ~/.bash_profile:
Code Listing 1.15: Editing bash_profile
This way, you'll get the same prompt setting whether you start a login or
Well, there you have it. Now, have some fun and whip up some nifty colorized
rxvt is a great little xterm that
happens to have a good amount of documentation related to escape sequences
tucked in the doc directory included in the source tarball.
aterm is another terminal
program, based on rxvt. It supports several nice visual features, like
transparency and tinting.
is a theme engine for all different kinds of terminals. Check out some great
screenshots of bashish in action!
About the author
Daniel Robbins lives in Albuquerque, New Mexico. He was the President/CEO of
Gentoo Technologies Inc., the Chief Architect of the Gentoo Project and is a
contributing author of several books published by MacMillan: Caldera OpenLinux
Unleashed, SuSE Linux Unleashed, and Samba Unleashed. Daniel has been involved
with computers in some fashion since the second grade when he was first exposed
to the Logo programming language and a potentially lethal dose of Pac Man. This
probably explains why he has since served as a Lead Graphic Artist at SONY
Electronic Publishing/Psygnosis. Daniel enjoys spending time with his wife Mary
and his new baby daughter, Hadassah. You can contact Daniel at