calculate md5 hashes of chunks of a file, configurable block size

md5chunks.py

#!/usr/bin/env python

from optparse import OptionParser
import hashlib
import sys

parser = OptionParser()
parser.add_option("-b", "--blocksize", dest="blocksize", type=int, default=1024,
                  help="Specify blocksize", metavar="blocksize")

(options, args) = parser.parse_args()

if len(args) == 0:
    print "Please specify a filename"
    sys.exit(1)

f = open(args[0], 'r')
c = 0

while 1:
    c += 1
    block = f.read(options.blocksize)
    if not block:
        break
    m = hashlib.md5()
    m.update(block)
    md5 = m.hexdigest()
    print "%d block is %s" % (c, md5)

Thanks for this. I didn't know how to get multiple md5 values for a Mac manifest file and this solved it for me. I appreciate your effort!