Cleaning out my hard drive and I found this self replicating python file I wrote 5 years ago. Saving for posterity.

self_replicating_file.py

#!/usr/bin/env python

# use unittest to test if new file equals original, will
# fail test if it does not.
import unittest

# Get the file name of 'this' file. Will be 'file.py'
ORIG_FILE_NAME = __file__

# Get the contents of the ORIGINAL FILE file.
original_files_contents = open(ORIG_FILE_NAME,'rb').read()

# Create new file name by splitting original name 'file' and 'py'
# and putting '_new' between them. New file is 'file_new.py'.
NEW_FILE_NAME = ("%s_%s.%s" % (ORIG_FILE_NAME.split('.')[0], "new",
                        ORIG_FILE_NAME.split('.')[1] ) )

# Write the contents of the original file to the new file.
with open(NEW_FILE_NAME, 'wb') as file:
    file.write(original_files_contents)

# Test that new file has same contents as original
class TestClone(unittest.TestCase):
    def test_diff_contents(self):
        f1 = open(ORIG_FILE_NAME, 'rb').read()
        f2 = open(NEW_FILE_NAME, 'rb').read()
        self.assertEqual(f1, f2)

if __name__ == "__main__":
    unittest.main()