Rename files in a directory to have ordinal prefixes, sorted by US date (mm-dd-yyyy) in filename

date_rename.py

import os
import re


US_DATE_REGEX = re.compile(r'(\d\d)-(\d\d)-(\d\d\d\d)')

def parse_name(name):
    match = US_DATE_REGEX.search(os.path.basename(name))
    if match:
        month, day, year = map(int, match.groups())
        return (year, month, day)

def sort_names(filenames):
    sortable = []
    for name in filenames:
        ordinal = parse_name(name)
        if ordinal:
            sortable.append((ordinal, name))
    return [name for _, name in sorted(sortable)]

def safe_rename(src, dest, undo_file=None):
    if os.name == 'nt':
        move_cmd = 'move'
    else:
        move_cmd = 'mv'
    escaped_src = src.replace('"', '\\"')
    escaped_dest = dest.replace('"', '\\"')
    if undo_file:
        undo_file.write('{} '.format(move_cmd))
        undo_file.write('"{}" "{}"\n'.format(escaped_dest, escaped_src))
    os.rename(src, dest)

def rename_enumerated(filenames, undo_file):
    for n, name in enumerate(sort_names(filenames)):
        new_basename = '{}. {}'.format(n + 1, os.path.basename(name))
        new_name = os.path.join(os.path.dirname(name), new_basename)
        safe_rename(name, new_name, undo_file)

def main(d):
    if os.name == 'nt':
        undo_script = 'undo.bat'
    else:
        undo_script = 'undo.sh'
    undo_path = os.path.join(d, undo_script)

    filenames = [os.path.join(d, filename) for filename in os.listdir(d)]
    with open(undo_path, 'w') as undo_file:
        rename_enumerated(sort_names(filenames), undo_file)

if __name__ == '__main__':
    d = input("Which dir?\n")
    main(d)