bulk_rename.py

#!/usr/bin/env python

import argparse
from os import chdir, getcwd, listdir
from os.path import realpath
from shutil import move

class PushdContext:
    cwd = None
    original_dir = None

    def __init__(self, dirname):
        self.cwd = realpath(dirname)

    def __enter__(self):
        self.original_dir = getcwd()
        chdir(self.cwd)
        return self

    def __exit__(self, type, value, tb):
        chdir(self.original_dir)

def pushd(dirname):
    return PushdContext(dirname)

def bulk_rename():
    parser = argparse.ArgumentParser(description='Bulk rename files.')
    parser.add_argument('directory', metavar='DIR', help='a directory')
    parser.add_argument('indices', metavar='N', type=int,
            nargs='+',choices=range(1, 13), help='an index')
    args = parser.parse_args()
    with pushd(args.directory) as ctx:
        for f in listdir(ctx.cwd):
            print('Renaming "%s"' % f)
            ext = f.split('.', 1)[1]
            name = f.split('.', 1)[0]
            parts = name.split('_')
            new_name = ''
            for i in args.indices:
                new_name += parts[i-1] + '_'
            new_name = '%s.%s' % (new_name[:-1], ext)
            print('\tto "%s"...' % new_name)
            move(f, new_name)

if __name__ == "__main__":
    bulk_rename()