Get md5 of file without getting all content. It's very pythonic

md5sum.py

#!/usr/bin/env python

import sys, hashlib

m = hashlib.md5()

with open(sys.argv[1], "rb") as fp:
    for chunk in iter(lambda :fp.read(128 * m.block_size), ""):
        m.update(chunk)

    print m.hexdigest()

juven@xxx:~$ time md5sum access_log-20120213 
348ee067cdbdf285c632c459d65298b1  access_log-20120213

real    0m35.074s
user    0m5.440s
sys 0m2.200s
juven@xxx:~$ vi md5.py
juven@xxx:~$ time python md5.py access_log-20120213 
348ee067cdbdf285c632c459d65298b1

real    0m34.478s
user    0m7.336s
sys 0m2.856s

效率看起来还不错哦。

附上参考地址： http://stackoverflow.com/questions/1131220/get-md5-hash-of-a-files-without-open-it-in-python