Simple Directory diff'er

dirdiff.py

import os, hashlib, argparse, sys

def hash_dir(directory):
    dirhashes = {}
    for subdir, dirs, files in os.walk(directory):
        for afile in files:
            filepath = os.path.join(subdir,afile)
            filepath_noparent = filepath.split(directory,1)[1]
            if os.path.islink(filepath):
                continue
            try:
                with open(filepath,"rb") as currfile:
                    sha1 = hashlib.sha1()
                    while True:
                        filedata = currfile.read(65536)
                        if not filedata:
                            break
                        sha1.update(filedata)
                sha1hash = sha1.hexdigest()
                dirhashes[filepath_noparent] = sha1hash
            except IOError as e:
                print "Error opening " + filepath + ". Ignoring."
    return dirhashes

def main(argv):
    argparser = argparse.ArgumentParser(description="Directory diff-er for finding changed files between two directory trees",
                                        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    argparser.add_argument('dir1',action='store', type=str, metavar="directory1")
    argparser.add_argument('dir2',action='store', type=str, metavar="directory2")

    args = argparser.parse_args(argv)
    dir1hashes = {}
    dir2hashes = {}
    diffhashes = []
    dir1only = []

    dir1hashes = hash_dir(args.dir1)

    print "All hashes calculated for " + args.dir1

    dir2hashes = hash_dir(args.dir2)

    print "All hashes calculated for " + args.dir2

    for filename, hash in dir1hashes.iteritems():
        if filename in dir2hashes:
            if dir1hashes[filename] != dir2hashes[filename]:
                print filename + " has a different hash."
                diffhashes.append(filename)
            # get rid of the k,v pair from dir2hashes so we are only left with the non matches
            del dir2hashes[filename]

        else:
            print filename + " was not present in " + args.dir2
            dir1only.append(filename)

    with open("results.txt","wb+") as resultsfile:
        resultsfile.write("Files with different hashes:\n")
        diffhashes.sort()
        for entry in diffhashes:
            resultsfile.write(entry+"\n")
        resultsfile.write("\n\nFiles only in " + args.dir1+"\n")
        for entry in dir1only:
            resultsfile.write(entry+"\n")
        resultsfile.write("\n\nFiles only in " + args.dir2+"\n")
        for entry,hash in dir2hashes.iteritems():
            resultsfile.write(entry+"\n")

    print "All done."


if __name__ == "__main__":
    print("Directory Differ")
    main(sys.argv[1:])