Regex File-Renaming Utility

rename_files.py

#!/usr/bin/python

"""
This is a command-line batch file-renaming utility.
It uses regular expressions to transform filenames.
This is especially helpful on Mac since Mac OS X does not include the Linux 'rename' command.
Run with no arguments for help info.

Author: Simon Radford (simonradf@gmail.com)
"""

import sys
import os
import re

def main(dir, match_expr = r"([^.]*)", replace_expr = "(1).txt", dry_run = True, rename_hidden_files = False):
    print "match_expr   =", match_expr
    print "replace_expr =", replace_expr
    for filename in os.listdir(dir):
        pathname = os.path.join(dir, filename)
        match = re.match(match_expr, filename)
        if match and match.end() == len(filename) and os.path.isfile(pathname) and (rename_hidden_files or not filename.startswith('.')):
            new_filename = replace_expr
            for n, group in enumerate(match.groups()):
                if group is not None:
                    group_name = "(%s)" % (n + 1)
                    new_filename = new_filename.replace(group_name, group)
            new_pathname = os.path.join(dir, new_filename)
            print "%s %s to %s" % ("Would rename" if dry_run else "Renaming", pathname, new_pathname)
            if not dry_run:
                os.rename(pathname, new_pathname)
        else:
            print "%s %s" % ("Would not rename" if dry_run else "Not renaming", pathname)

if __name__ == "__main__":
    args = sys.argv[1:]
    dry_run = True
    rename_hidden_files = False
    while True:
        if args and args[-1] == "-f":
            dry_run = False
            del args[-1]
        elif args and args[-1] == "-h":
            rename_hidden_files = True
            del args[-1]
        else:
            break
    if not 1 <= len(args) <= 3:
        print "Usage: %s directory [match_expr] [replace_expr] [-f] [-h]" % sys.argv[0]
        print "Use -f option for a wet run."
        print "Use -h option to rename hidden files as well."
        print
        print "For each file in directory, if the filename completely matches the match_expr, renames it to the replace_expr."
        print "The match_expr can be any regular expression recognized by Python's 're' module."
        print "The replace_expr is a string that can contain (1) to reference the first parenthesized regex group, (2) for the second, etc."
        print "The default will be to append '.txt' to all filenames that do not contain a dot."
        print "Make sure to enclose your regular expressions in quotes on the command line to prevent the shell from expanding them."
        sys.exit(1)
    if dry_run:
        print "Performing dry run. Use -f option for a wet run."
    else:
        print "Performing wet run."
    main(*args, dry_run = dry_run, rename_hidden_files = rename_hidden_files)