perror utility in python

pyrror.py

#!/usr/bin/env python

import sys
import os

def usage():
    print 'usage: {} [errno]'.format(sys.argv[0])
    sys.exit(1)

if __name__ == '__main__':
    if len(sys.argv) != 2:
        usage()
    try:
        print os.strerror(int(sys.argv[1]))
    except ValueError:
        usage()