title: spawn-fcgi: child exited with: 13
body: <pre><code># spawn-fcgi -s /var/run/munin-fastcgi-html.sock -U nginx -u munin -g munin munin-fastcgi-html
  spawn-fcgi: child exited with: 13    
  </code></pre>
  
  <p>The .sock is created, but filesize is 0 bytes.
  What does code 13 stand for?</p>