Writing multiple output files in Python (based on command line argument)

gistfile1.py

#!/usr/bin/env python

import sys

if len(sys.argv) < 2:
    sys.stderr.write("usage: write_two_files.py <filename prefix>\n")
    sys.exit()

prefix = sys.argv[1]

first_filename = prefix + ".dog"

with open(first_filename, 'w') as first:
    first.write("woof woof\n")

second_filename = prefix + ".cat"

with open(second_filename, 'w') as second:
    second.write("hiss hiss <pees on floor>\n")

if you run

python write_two_files.py foo

you get "foo.cat" and "foo.dog"