File compare

diff.py

#!/usr/bin/env python
# author:op
# this script tries to loop every line in file1 and compare it to all lines in file2
# spits out what's not matching 

import argparse

parser = argparse.ArgumentParser(description='Find difference between file1.txt and file2.txt')
parser.add_argument('filename1')
parser.add_argument('filename2')
args = parser.parse_args()

with open(args.filename1,'r') as f1:
    if '\r\n' in f1.read():
        f1.seek(0)
        f1list = f1.read().split('\r\n')
    else:
        f1.seek(0)
        f1list = f1.read().split('\n')
        
with open(args.filename2,'r') as f2:
    if '\r\n' in f2.read():
        f2.seek(0)
        f2list = f2.read().split('\r\n')
    else:
        f2.seek(0)
        f2list = f2.read().split('\n')        

#print f1list[0:5]
#print ('=================================================================')
#print f2list[0:5]

for i in f1list:
    if i not in f2list:
        print i