#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright (c) 2012 Jérémie DECOCK (http://www.jdhp.org)

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import argparse
import hashlib

CHUNK_SIZE = 2**12

def main():
    """Main function"""

    # PARSE OPTIONS ###########################################################

    parser = argparse.ArgumentParser(description='Compute the md5sum of a file with "hashlib".')
    parser.add_argument("filenames", nargs='+', type=file, metavar="FILE", help="file to read")
    args = parser.parse_args()

    # COMPUTE HASHS ###########################################################

    for file_descriptor in args.filenames:
        hash = hashlib.md5()

        try:
            data = file_descriptor.read(CHUNK_SIZE)
            while data:
                hash.update(data)
                data = file_descriptor.read(CHUNK_SIZE)
        finally:
            file_descriptor.close()

        print hash.hexdigest()        # str

if __name__ == '__main__': main()


Add a python snippet (compute md5sums).