Script to rename all jpg files in a folder

rename.py

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

import os
from os.path import isfile, join
from math import log10, ceil


def get_files(folder):
    onlyfiles = [f for f in os.listdir(folder) if isfile(join(folder, f))]
    image_files = filter(lambda f: f.endswith('.jpg') or f.endswith('.JPG'),
                         onlyfiles)
    image_files = sorted(image_files)
    return image_files


def main(folder, name, start, print_only):
    image_files = get_files(folder)
    digits = int(ceil(log10(start + len(image_files))))
    rename = []

    number = start
    for filename in image_files:
        new_name = "%s-%s.jpg" % (name, str(number).zfill(digits))
        rename.append({'old': filename, 'new': new_name})
        number += 1

    for file_dict in rename:
        print("%s -> %s" % (file_dict['old'], file_dict['new']))
        if not print_only:
            os.rename(file_dict['old'], file_dict['new'])

if __name__ == '__main__':
    from argparse import ArgumentParser

    parser = ArgumentParser()

    # Add more options if you like
    parser.add_argument("-n", "--name",
                        dest="name",
                        required=True,
                        help="name to use in [name]-[number].jpg scheme",
                        metavar="NAME")
    parser.add_argument("-f", "--folder",
                        dest="folder",
                        default=".",
                        help="folder to look in",
                        metavar="FOLDER")
    parser.add_argument("-s", "--start",
                        dest="start",
                        default=1,
                        type=int,
                        help="number to start with",
                        metavar="NUM")
    parser.add_argument("-p", "--printonly",
                        dest="print_only",
                        default=False,
                        action="store_true",
                        help="only print changes that would be done")

    args = parser.parse_args()
    main(args.folder, args.name, args.start, args.print_only)