Python - Consistency.py

import os
import re

# Filenames consist of a username (alphanumeric, 3-12 characters)
# and a date (four digit year, two digit month, two digit day),
# and an extension. They should end up in the format
# year-month-day-username.extension.

# Example: kennethlove2-2012-04-29.txt becomes 2012-04-29-kennethlove2.txt

def cleanup(path):
    for dirs, dirp, files in os.walk('path'):
        for fil in files:
            result = re.search(r'([a-z0-9]+)(-)(\d{4}-\d{2}-\d{2})([.a-z]+)', fil)
            if result:
               replace = result.group(3) + result.group(2) + result.group(1) + result.group(4)
               os.rename(os.path.join(path, fil),os.path.join(path, replace))