Customizing your Bash Prompt

Customizing Your Prompt in BASH

You can customize your bash shell prompt by setting the environment variable PS1 in your .bashrc file. You set PS1 to a string for your prompt. This string can incldue control sequences, which begin with a \.

If you do this

PS1="Pay attention, fool!"

your shell prompt will be "Pay attention, fool!". Note that there are no spaces around the = sign. If you have spaces there, you will get an error statement from bash.

Using Control Sequences For example, the \u tells bash to insert the name of the current user into the prompt string. If your user name is morrison, your prompt string will be "morrison—>".

If you are a csh or tcsh user and, like many such people, are used to having a history number in your prompt string, bash can do this similarly to the C shell: if the sequence \! is used in the prompt string, it will substitute the history number. Thus, if you define your prompt string to be

PS1="\u[\!]> "

your prompt will be look like morrison[1]>, then morrison[2]>, and so on as you keep issuing commands.

If you type

!number

into bash, it will execute the command with history number number.

A very useful way to set up your prompt string is so that it always contains your current working directory. This way, you needn't type pwd to remember where you are. Here's how.

PS1="\w--> "

This table provides a list of control sequences that are available.

Prompt String Control Sequences
Code	Feature
`\a`	The ASCII bell character (007)
`\A`	The current time in 24-hour HH:MM format
`\d`	The date in "Weekday Month Day" format
`\D`	{format} The format is passed to strftime(3) and the result is inserted into the prompt string; an empty format results in a locale-specific time representation; the braces are required
`\e`	The ASCII escape character (033)
`\H`	The hostname
`\h`	The hostname up to the first "."
`\j`	The number of jobs currently managed by the shell
`\l`	The basename of the shell's terminal device name
`\n`	A carriage return and line feed
`\r`	A carriage return
`\s`	The name of the shell
`\T`	The current time in 12-hour HH:MM:SS format
`\t`	The current time in HH:MM:SS format
`\@`	The current time in 12-hour a.m./p.m. format
`\u`	The username of the current user
`\v`	The version of bash (e.g., 2.00)
`\V`	The release of bash; the version and patchlevel (e.g., 2.00.0)
`\w`	The current working directory
`\W`	The basename of the current working directory
`\#`	The command number of the current command
`\!`	The history number of the current command
`\$`	If the effective UID is 0, print a #, otherwise print a $
`\nnn`	Character code in octal
`\\`	Print a backslash
`\[`	Begin a sequence of non-printing characters, such as terminal control sequences
`\]`	End a sequence of non-printing characters

PS2 is called the secondary prompt string Its default value is >. It is used when you type an incomplete line and hit RETURN, as an indication that you must finish your command. You can customize it in the same manner as PS1.