The shell variable PS1 holds your bash prompt. You might want to change it to serve your needs best. Here is how to:

General

• non-printing escape sequences in your prompt have to be inclosed in \[\e[ and \] so your shell can correctly count its prompt's length
• we recommend to highlight your prompt on production machines
• you can also show different root prompts for each user (if you not directly login with root)

Information

• \u: current username
• \h: hostname up to the first ., \H: full hostname
• \w: current working directory, \W: same, but only the basename
• $(__git_ps1 "%s"): your current git branch if you're in a git directory, otherwise nothing

• \$: if the effective UID is 0: #, otherwise $

• \d: the date in "Weekday Month Date" format (e.g., "Tue May 26")
• \t: the current time in 24-hour HH:MM:SS format, \T: same, but 12-hour format, \@: same, but in 12-hour am/pm format
• \n: newline
• \r: carriage return
• \\: backslash

Colors & Styles

• colors have to be escaped (see General), color codes should be followed by an m
• put \[\e[‹code›m\] and \[\e[0m\] around the part of your prompt you want to style
• where ‹code› is a ;-chain of:
  • x: attribute of the text
  • 3y: foreground color
  • 4y: background color
• x:
  • 0: normal
  • 1: bold
  • 4: underline
  • 7: reverse
• y is the color:
  • 0 black
  • 1 red
  • 2 green
  • 3 yellow
  • 4 blue
  • 5 magenta
  • 6 cyan
  • 7 white
• example: \[\e[0;33m\]prompt:\[\e[0m\]

Save your settings by writing export PS1='...' to your .bashrc or .profile.

Examples

export PS1='\h \w$(__git_ps1 "(%s)") \$ '
=> mycomputer ~/apps/chess/tmp(master) $ _

export PS1='\[\e[33m\]\h\[\e[0m\]:\W\[\e[33m\]$(__git_ps1 "(%s)")\[\e[0m\] \u\$ '
=> mycomputer:tmp(master) tom$ _

# Henning's awesome TRON prompt 2.0.2 with current Git branch and success state of the last command (the syntax coloring here does not do it justice):
export PS1='`if [ $? = 0 ]; then echo "\[\033[01;32m\]✔"; else echo "\[\033[01;31m\]✘"; fi` \[\033[01;30m\]\h\[\033[01;34m\] \w\[\033[35m\]$(__git_ps1 " %s") \[\033[01;30m\]>\[\033[00m\] '
=> ✔ mycomputer ~/projects/platforms master > _

# Arne's epic timestamped prompt with return status indicator and status-colored (green if fresh, or red if unstaged, or yellow if staged) git branch:
export PS1='\[\e[01;30m\]\t`if [ $? = 0 ]; then echo "\[\e[32m\] ✔ "; else echo "\[\e[31m\] ✘ "; fi`\[\e[00;37m\]\u\[\e[01;37m\]:`[[ $(git status 2> /dev/null) =~ Changes\ to\ be\ committed: ]] && echo "\[\e[33m\]" || echo "\[\e[31m\]"``[[ ! $(git status 2> /dev/null) =~ nothing\ to\ commit,\ working\ .+\ clean ]] || echo "\[\e[32m\]"`$(__git_ps1 "(%s)\[\e[00m\]")\[\e[01;34m\]\w\[\e[00m\]\$ '
=> 03:13:37 ✔ arne:(master)~/projects/geordi$ _

# Arne's danger prompt for root use. No git information and alarming red and yellow (which you can't see here):
export PS1='\[\e[01;30m\]\t \[\e[31m\]\u\[\e[37m\]:\[\e[33m\]\w\[\e[31m\]\$\[\033[00m\] '
=> 03:13:37 root:/tmp/foo# _

# Kim's mix of those above with small changes. TRON promt with timestamp, return status indicator, hostname, git informations and working directory (but all non-bold).
export PS1='\[\033[01;30m\]\t `if [ $? = 0 ]; then echo "\[\033[01;32m\]ツ"; else echo "\[\033[01;31m\]✗"; fi` \[\033[00;32m\]\h\[\033[00;37m\]:\[\033[31m\]$(__git_ps1 "(%s)\[\033[01m\]")\[\033[00;34m\]\w\[\033[00m\] >'
=> 03:13:37 ツ mycomputer:(master)~/code/foo >_

# Kim's root prompt (the same as above without git and the hostname is red)
export PS1='\[\033[01;30m\]\t `if [ $? = 0 ]; then echo "\[\033[01;32m\]ツ"; else echo "\[\033[01;31m\]✗"; fi` \[\033[00;31m\]\h\[\033[00;37m\]:\[\033[00;34m\]\w\[\033[00m\] >'
=> 03:13:37 ツ mycomputer:~/code/foo >_

# Martin's prompt
export PS1='`if [ $? = 0 ]; then echo "\[\033[01;32m\]✔"; else echo "\[\033[01;31m\]✘"; fi` \[\033[01;30m\]\h\[\033[01;34m\] \w\[\033[35m\]$(__git_ps1 " %s") \[\033[01;31m\]\n>\[\033[00m\] '
=> ✔ mycomputer ~/code/foo master 
   > _

# Henning's danger prompt for root 2.1
export PS1='${debian_chroot:+($debian_chroot)}\[\033[43;30m\]\u@\h\[\033[00m\] \[\033[01;33m\]\w\[\033[00m\] \[\033[01;31m\]>\[\033[00m\] '
=> user@mycomputer ~/code/foo > _

See the attached screenshot for colorful examples of the above prompt settings (the user is arne on machine happycat in directory ~/code/geordi on the master branch).