All together

gistfile1.txt

ps1_venv () {
    if [ -n "$VIRTUAL_ENV" ]; then
        printf ' (%s)' `basename $VIRTUAL_ENV`
    fi
}

ps1_err () {
    errcode=$?
    local prompt=$1
    printf "$(ansi_hash ${prompt})"
    if [ "$errcode" != 0 ]; then
        printf " \e[0;31m($errcode)"
    fi
}

ansi_hash () {
    # Colors a string based on a hash of its contents
    # Usage: ansi_hash [-s style] [-o offset] text ..
    style=0 # default is normal, 1 is bold, 4 is underline
    offset=30 # default is normal, 90 is high intensity

    OPTIND=0
    while getopts s:o: a
    do case "$a" in
            s)	style="$OPTARG";;
	    o)	offset="$OPTARG";;
	    [?])	print >&2 "Usage: $0 [-s style] [-o offset] text ...";;
	esac
    done
    shift `expr $OPTIND - 1`

    hashme="$@"
    hex=`echo "$hashme" | md5sum | cut -b 1-6`
    decimal=$((0x$hex))
    part=`expr $decimal % 8 + $offset`
    printf '\e[%s;%sm%s\e[0m' $style $part $hashme
}
export PS1="\$(ps1_err \" \w\") \$(ansi_hash \$(__git_ps1))\$(ansi_hash \" \$(ps1_venv)\")\e[0m\n▷ "