Diff lines from file a and b, all lines from b that are not in a will be displayed

notin.py

#!/usr/bin/env python
import sys

def get_tokens(src):
	file   = open(src)
	return [token.strip(' \t\n\r') for token in file.readlines()]

def diff_tokens(a, b):
	return [x for x in a if x not in b]

def main():
	a = get_tokens(sys.argv[1])
	b = get_tokens(sys.argv[2])

	tokens = diff_tokens(a, b)
	for token in tokens:
		print "%s" % token

if __name__ == "__main__":
	main()