Use jsmin() to minify a js-file or a folder containing js-files.

minify.py

import os;
import sys;
from jsmin import jsmin;

if len(sys.argv) < 2:
    print '- Requires .js-file or directory containing js.files';
    exit();

input = os.path.abspath(sys.argv[1]);
name = os.path.splitext(input)[0] + '.min.js';
files = [];

if os.path.isfile(input):
    files.append(input);

if os.path.isdir(input):
    for file in os.listdir(input):
        if file.endswith('js'):
            files.append(os.path.join(input, file));

if len(files) == 0:
    print '- No files';
else:
    content = '';
    for file in files:
        with open(file) as data:
            minified = data.read();
            content += jsmin(minified);
    
    if not content:
        print '- Nothing was done...';
    else:
        f = open(name, 'w');
        f.write(content.replace('\n', '').replace('\r', ''));
        f.close();
        print '- Success';