How to customize the command prompt in bash

In the bash shell, the command prompt is the text shown when you are being prompted for input. On most systems, it looks like this:

In the prompt, you can have information before you run any commands. For example, the prompt above shows you the following.

1. Who you are (a user named user).
2. Where you are (a computer named myhost).
3. What your working directory is (~, an abbreviation for your home directory).

Perhaps most important is the dollar sign ("$"), a special character that indicates you are logged in as a non-root user. If you were currently logged in as root, this character would be a pound sign ("#") instead.

The string representing the prompt is stored in the special environment variable named PS1. For the prompt above, its value looks like the following.

"\u@\h:\W\$ "

There are four special characters in this string: \u, \h, \W, \$. These are escaped character sequences that are replaced with actual values every time the prompt is displayed.

Special characters

The special character sequences listed in the table below can be used in the bash shell prompt.

Changing the prompt for the current session

You can set the PS1 environment variable as you would any other variable in bash, with the statement form NAME=VALUE. So to set the standard prompt, you could type the following at the command line.

PS1="\u@\h:\W\$ "

…And your prompt will immediately change. Notice the final space after the dollar sign in the string. It is an extra space after your prompt, which makes it easier to differentiate the commands you type from the prompt. The extra space isn't necessary, but we recommend it.

Notice that in the command, there are no spaces between PS1, =, and the string.

Changing the prompt for all future sessions

To change the prompt for every new session, you must edit your bash startup files. Every time you start a terminal session, the following files, if they exist, are read in and executed as scripts:

/etc/profile
~/.bash_profile
~/.bash_login
~/.profile

The first file, /etc/profile, is a startup script for users on the system who start a bash session. To change the prompt for every user, you must edit this file, and you need superuser privileges to do so.

sudo vi /etc/profile

For example, the command above prompts you for your password. If you're on the sudoers list, open the universal bash startup file as the superuser, using the vi editor.

The other three files are looked for in the order listed above and executed after /etc/profile. These three files live in your home directory, so they are executed only for you. They may define PS1 in more than one place, so read the files carefully to see how they're configured on your system. For instance, many systems use a different PS1 value depending on whether or not your terminal supports color.

Any of the three files may exist and be used for your bash session. However, if there is more than one, they are executed in the order listed.

If you don't want to delete or change lines in your startup files, you can add a new PS1= statement to the end of the to override previously-defined prompts.

Adding color to your prompt

If you're using a terminal that supports color (and you probably are), you can add color to your prompt. Colors are added using special character sequences that follow this format:

For instance, the prompt string:

PS1="\e[1;35mThis is bright purple. \e[0;35m...and this is dark purple.\e[m "

Will produce a prompt that looks like this:

Here are the colors you can use, and the numbers that specify them:

Here are examples, and what they look like:

PS1="\e[0;31mRed \e[0;32mGreen \e[0;33mBrown \e[0;34mBlue \e[0;35mPurple \e[0;36mCyan \e[0;37mGray \e[m"

PS1="Underlined: \e[4;31mRed \e[4;32mGreen \e[4;33mBrown \e[4;34mBlue \e[4;35mPurple \e[4;36mCyan \e[4;37mGray \e[m"

PS1="\e[44m\e[1;35mBright purple on a blue background\e[m "