Colorize the last portion of directory name in your shell prompt

color_ps1.sh

function short_pwd () {
    pwd | sed -e "s@$HOME@~@"
}

function ps1_dir () {
    dn=$(dirname `short_pwd`)
    # in ~ yields "./" that becomes ""
    # in / yields "//" that becomes "/"
    echo "$dn/" | sed -e 's@^\./$@@' | sed -e 's@^//$@/@'
}

function ps1_base() {
    # in ~ yields "~"
    # in / yields "/" that becomes ""
    basename `short_pwd` | sed -e 's@^/$@@'
}

RED="\[\033[0;31m\]"
YELLOW="\[\033[0;33m\]"
GREEN="\[\033[0;32m\]"
BLUE="\[\033[0;34m\]"
NO_COLOUR="\[\033[0m\]"

PS1="$GREEN\$(ps1_dir)$YELLOW\$(ps1_base)$NO_COLOUR "