cat.py

#!/usr/bin/python
# Filename: cat.py

import sys 

def readfile(filename):
    '''Print a file to the standard output.'''
    f = file(filename)
    while True:
	line = f.readline()
	if len(line) == 0:
		break
	print line, # notice comma
    f.close()

# Script starts from here
if len(sys.argv) < 2:
 	print 'No action specified.'
	sys.exit()

if sys.argv[1].startswith('--'):
	option = sys.argv[1][2:]
	# fetch sys.argv[1] but without the first two characters
	if option == 'version':
		print 'Version 1.2'
	elif option == 'help':
		print '''\
This program prints files to the standard output.
Any number of files can be specified.
Options include:
  --version :Prints the version numver
  --help    :Display this help'''
	else:
	  	print 'Unknown option.'
	sys.exit()
else:
	for filename in sys.argv[1:]:
		readfile(filename)