python: download url to file with progress bar

This is an alternative answer for a question on stackoverflow:
http://stackoverflow.com/a/22776/286994

I modified the answer a bit, using .format instead of % string formatting and sys.stdout.write(), and posted it on gist github: https://gist.github.com/3176958

#!/usr/bin/python
# Improve http://stackoverflow.com/a/22776/286994
# (using .format() instead of % string formatting)

import sys
import urllib2

file_name = url.split('/')[-1]
u = urllib2.urlopen(url)
f = open(file_name, 'wb')
meta = u.info()
file_size = int(meta.getheaders("Content-Length")[0])
print("Downloading: {0} Bytes: {1}".format(url, file_size))

file_size_dl = 0
block_sz = 8192
while True:
    buffer = u.read(block_sz)
    if not buffer:
        break

    file_size_dl += len(buffer)
    f.write(buffer)
    p = float(file_size_dl) / file_size
    status = r"{0}  [{1:.2%}]".format(file_size_dl, p)
    status = status + chr(8)*(len(status)+1)
    sys.stdout.write(status)

f.close()

I'm using this solution for the kernel mainline ppa downloader: https://github.com/medigeek/kmp-downloader