Python Command Line Arguments (Windows)

Question

I am running 32-bit Windows 7 and Python 2.7.

I am trying to write a command line Python script that can run from CMD. I am trying to assign a value to sys.argv[1]. The aim of my script is to calculate the MD5 hash value of a file. This file will be inputted when the script is invoked in the command line and so, sys.argv[1] should represent the file to be hashed.

Here's my code below:

import sys
import hashlib

filename = sys.argv[1]

def md5Checksum(filePath):
    fh = open(filePath, 'rb')
    m = hashlib.md5()
    while True:
        data = fh.read(8192)
        if not data:
            break
        m.update(data)
    return m.hexdigest()

# print len(sys.argv)
print 'The MD5 checksum of text.txt is', md5Checksum(filename)

Whenver I run this script, I receive an error:

filename = sys.argv[1]
IndexError: list index out of range

To call my script, I have been writing "script.py test.txt" for example. Both the script and the source file are in the same directory. I have tested len(sys.argv) and it only comes back as containing one value, that being the python script name.

Any suggestions? I can only assume it is how I am invoking the code through CMD

You have a dangling open file handle there. Use with open(filePath, 'rb') as fh: instead. — wim

newtover newtover · Accepted Answer · 2012-03-26T22:17:37

try to run the script using python script.py test.txt, you might have a broken association of the interpreter with the .py extention.

Python Command Line Arguments (Windows)

4 Answers