random-cow.py

#!/usr/bin/env python
# coding: utf-8

import sys
import subprocess
import random


def main(msg):
    out, err = subprocess.Popen('cowsay -l', shell=True, stdout=subprocess.PIPE).communicate()
    files = (" ".join(out.split("\n")[1:-1])).split(" ")
    choice = random.choice(files)
    subprocess.call("cowsay -f {} {}".format(choice, msg), shell=True)


if __name__ == "__main__":
    message = " ".join(sys.argv[1:])
    main(message)