Get a list of filenames using argparse (updated to use default formatter)

argparse_files.py

import argparse
import os
import glob

def main():
    #Does not currently have support to read files from folders recursively
    parser = argparse.ArgumentParser(description='Read in a file or set of files, and return the result.', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser.add_argument('path', nargs='+', help='Path of a file or a folder of files.')
    parser.add_argument('-e', '--extension', action='append', default=[''], help='File extension to filter by.')
    args = parser.parse_args()

    # Parse paths
    full_paths = [os.path.join(os.getcwd(), path) for path in args.path]
    files = set()
    for path in full_paths:
        if os.path.isfile(path):
            files.add(path)
        else:
            for ext in args.extension:
                files |= set(glob.glob(path + '/*' + ext))

    for f in files:
        print f

if __name__ == '__main__':
    main()

Updated, with multiple extension