A dos2unix python clone that supports recusrively finding files (doesn't suck)

dos2unix.py

import argparse
import os
import re

parser = argparse.ArgumentParser("Convert line endings to \\n")
parser.add_argument('--excluded', help='Patterns of files or directories to exclude', nargs='*')
parser.add_argument('--quiet', '-q', help='Suppress non-error output', action='store_true')
parser.add_argument('input', nargs='+', help='Files or directories to convert line endings in')

args = parser.parse_args()

def is_excluded(file):
    excluded = args.excluded
    if excluded is None:
        return False
    if isinstance(excluded, str):
        excluded = [str]
    for excluded in args.excluded:
        found = re.search(excluded, file)
        if found is not None and len(found.group(0)) > 0:
            return True
    return False

def process(file):
    if is_excluded(file):
        if not args.quiet:
            print(file, "was excluded from conversion")
        return
    try:
        original_lines = open(file).readlines()
    except UnicodeDecodeError:
        print("ignoring", file, "because it is a binary file")
        return
    new_lines = []
    for original_line in original_lines:
        for new_line in original_line.splitlines(False):
            new_line += '\n'
            new_lines.append(new_line)
    if original_lines == new_lines:
        return
    if not args.quiet:
        print("Converting lines in", file)
    open(file, "w+").writelines(new_lines)

for input_file in args.input:
    if os.path.isdir(input_file):
        for dir, subDirs, files in os.walk(input_file):
            for file in files:
                file = os.path.join(dir, file)
                process(file)
    else:
        process(input_file)