You can use the following and try :
$ ls -la chardet-1.0.1.tgz
-rwxr-xr-x 1 vinko vinko 179218 2008-10-20 17:49 chardet-1.0.1.tgz
$ python
Python 2.5.1 (r251:54863, Jul 31 2008, 22:53:39)
[GCC 4.1.2 (Ubuntu 4.1.2-0ubuntu4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> f = open('chardet-1.0.1.tgz','rb')
>>> f.seek(0,2)
>>> f.tell()
179218L