gistfile1.sh

# set variable identifying the git branch you work in (used in the prompt below)
bashrc_update_prompt() {
    git_branch=$(
        while [ "$PWD" != "/" ]; do
            if [ -d ".git/objects" ]; then
                git-branch 2>/dev/null | sed -ne 's/^\* //p'
                break
            fi

            cd ..
        done
    )
}

PROMPT_COMMAND=bashrc_update_prompt

...

if [ "$color_prompt" = yes ]; then
    PS1='\[\033[01;${ps1_color}m\]\u@\h\[\033[00m\]${debian_chroot:+($debian_chroot)}:\[\033[01;34m\]\w${git_branch:+\[\033[01;31m\](${git_branch})}\[\033[00m\]\$ '
else
    PS1='\u@\h${debian_chroot:+($debian_chroot)}:\w${git_branch:+(${git_branch})}\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;\u@\h${debian_chroot:+($debian_chroot)}: \w${git_branch:+(${git_branch})}\a\]$PS1"
    ;;
*)
    ;;
esac