Word count

#!/usr/bin/python2


import string
import sys
import collections
import csv


def main():
    """Counts words (and numbers) in a file"""
    try:
        infilename, outfilename = sys.argv[1:3]
    except IndexError:
        print "Usage: %s INFILE.txt OUTFILE.csv" % sys.argv[0]
        sys.exit(1)
    with open(infilename, 'r') as infile:
        text = infile.read()
    wordstring = text.translate(None, string.punctuation)
    wordlist = wordstring.split()
    counts = collections.Counter(wordlist)
    ordered = counts.most_common()
    with open(outfilename, 'w') as outfile:
        writer = csv.writer(outfile)
        writer.writerows(ordered)


if __name__ == '__main__':
    main()