title: What does process exit status 3 mean?
body: <p>I've seen the usage of exit status <code>3</code> in several <a href="http://code.djangoproject.com/browser/django/trunk/django/utils/autoreload.py#L84" rel="noreferrer">python scripts</a> that restart processes. As far as I know the convention is only about <code>0</code> and "not <code>0</code>" on Unix/Linux. </p>
  
  <p>Is there a convention defining other values like <code>3</code>.</p>