lowercase a directory recursively

lowercase.py

#!/usr/bin/env python
# coding: utf-8

version='1.0.0'

import os
import argparse
import sys

#parse args
parser = argparse.ArgumentParser(description='Recursively lowercase directory',formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument("dir", default='.', help='target directory')
args=parser.parse_args()

dir=args.dir

#lowercase tree
def lowercase_rename(root_dir,items):
  for item in items:
    old_name=os.path.join(root_dir, item)
    new_name=os.path.join(root_dir, item.lower())
    if new_name != old_name:
      print "renaming {} to {}".format(old_name, new_name)
      os.rename(old_name, new_name)

for dir_name, subdir_list, file_list in os.walk(dir,topdown=False):
  lowercase_rename(dir_name,file_list)
  lowercase_rename(dir_name,subdir_list)

new_dir=dir.lower()
if new_dir != dir:
  os.rename(dir, new_dir)