prompt() bash function

prompt.sh

prompt () {
    [[ $# = 1 ]] || exit 255
    mode="$1"

    case "$mode" in
	none)
	    export PS1=""
	    ;;
	off)
	    export PS1="$ "
	    ;;
	date)
	    export PS1="[\t]\$ "
	    ;;
	basic)
	    export PS1="\u:\w$ "
	    ;;
	full)
	    export PS1="[\t]\u:\w$ "
	    ;;
    esac
}

prompt basic