A small script that receives a folder path and a extension and list all files of that extension recursively starting in the folder informed

list_files.py

import os
import sys


def list_files_in(path, ext=None):
    for root, subdirs, files in os.walk(path):
        # print('\n\nroot = ' + root)

        for subdir in subdirs:
            list_files_in(subdir)

        for filename in files:
            if extension and filename.lower().endswith(ext.lower()):
                file_path = os.path.join(root, filename)
                print(file_path)


if __name__ == '__main__':
    try:
        starting_path = str(sys.argv[1])
        extension = str(sys.argv[2])
    except IndexError as ie:
        print 'Usage:\n\t' + sys.argv[0] + ' starting_path filter_extension'
        sys.exit(0)

    print('walk_dir = ' + starting_path)
    print('walk_dir (absolute) = ' + os.path.abspath(starting_path))
    list_files_in(starting_path, extension)