Ticket #1623: unused.py

#!/usr/bin/env python

import os
import json
import subprocess

with open(os.path.join('_locales', 'en_US', 'messages.json')) as file:
        msgids = json.load(file).keys()

for msgid in msgids:
        if subprocess.call(['grep', '--quiet', '--recursive', '--exclude-dir', '_locales', r'["\']\(i18n_\)\?%s["\']' % msgid]) != 0:
                print msgid