Wednesday, April 12, 2006

Hacking on your bash prompt

It's been a while since I did this so I'm writing it down in my external brain so that I can find it again:

prompt is store in the value PS1 so:

echo $PS1

gets you the current state, on recent redhat/fedora it appears to be:

[\u@\h \W]\$

which looks like:

[joelja@twin ~]$

The part of the bash manpage that talks about prompting says:

When executing interactively, bash displays the primary prompt PS1 when
it is ready to read a command, and the secondary prompt PS2 when it
needs more input to complete a command. Bash allows these prompt
strings to be customized by inserting a number of backslash-escaped
special characters that are decoded as follows:
\a an ASCII bell character (07)
\d the date in "Weekday Month Date" format (e.g., "Tue May
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
\e an ASCII escape character (033)
\h the hostname up to the first ‘.’
\H the hostname
\j the number of jobs currently managed by the shell
\l the basename of the shell’s terminal device name
\n newline
\r carriage return
\s the name of the shell, the basename of $0 (the portion
following the final slash)
\t the current time in 24-hour HH:MM:SS format
\T the current time in 12-hour HH:MM:SS format
\@ the current time in 12-hour am/pm format
\A the current time in 24-hour HH:MM format
\u the username of the current user
\v the version of bash (e.g., 2.00)
\V the release of bash, version + patch level (e.g., 2.00.0)
\w the current working directory, with $HOME abbreviated
with a tilde
\W the basename of the current working directory, with $HOME
abbreviated with a tilde
\! the history number of this command
\# the command number of this command
\$ if the effective UID is 0, a #, otherwise a $
\nnn the character corresponding to the octal number nnn
\\ a backslash
\[ begin a sequence of non-printing characters, which could
be used to embed a terminal control sequence into the
\] end a sequence of non-printing characters

I ended up using something slgihtly less visually busy, basically setting PS1 to:

export PS1="\u@\h \w \$"

in my .bashrc...

gets me a prompt that looks like:

joelja@darkwing ~ $

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