A Simple Python Script to Check Difference between Directories

I needed to track differences between software release packages, so that if anything changed dramatically, eg. some file missing or much smaller than expected, I can then get a notification to review the new potentially flawed package.

I found that filecmp.dircmp class in Python is spot on for this job. Here’s my snippet to compare differences of 2 directories recursively:

!/usr/bin/env python3
import argparse from filecmp import dircmp from os.path import getsize
changed_files = {} deleted_files = {} added_files = {}
def diff_file_size(file1, file2): return getsize(file2) - getsize(file1)
def diff_report(): for k, v in deleted_files.items(): print(k, v)
for k, v in added_files.items():
print(k, v)
for k, v in changed_files.items():
print(k, v)
def compare_dir(dir):
for changed_file in dir.diff_files:
file1 = "{0}/{1}".format(dir.left, changed_file)
file2 = "{0}/{1}".format(dir.right, changed_file)
changed_files[ file2 ] = diff_file_size(file1, file2)
for deleted_file in dir.left_only:
file1 = "{0}/{1}".format(dir.right, deleted_file)
deleted_files[ file1 ] = "DELETED!"
for added_file in dir.right_only:
file1 = "{0}/{1}".format(dir.right, added_file)
added_files[ file1 ] = "ADDED!"
for sub_dir in dir.subdirs.values():
def main():
parser = argparse.ArgumentParser(description="Usage for diff_dir.py")
parser.add_argument('--dir1', type=str, required=True)
parser.add_argument('--dir2', type=str, required=True)
args = parser.parse_args()
dir = dircmp(args.dir1, args.dir2)
if name__ == '__main':