distinct_files.py

import argparse
import contextlib

"""
Example usage:
python2.7 distinct_files.py --fileA=<fileA> --fileB=<fileB> > filenames_in_fileA_not_in_fileB.txt
"""

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--fileA", dest="fileA", type=argparse.FileType('r'))
    parser.add_argument("--fileB", dest="fileB", type=argparse.FileType('r'))
    args = parser.parse_args()
    with contextlib.closing(args.fileA), contextlib.closing(args.fileB):
        filenames_a = set([
            line.strip() for line in args.fileA.readlines()
        ])
        filenames_b = set([
            line.strip() for line in args.fileB.readlines()
        ])
        distinct_a = filenames_a - filenames_b
        for filename in distinct_a:
            print filename