title: How to determine what process is listening on OSX
body: <p>Trying to help configure Laravel Valet on a Mac running El Capitan, and the user had installed <code>MAMP</code> previously. <code>MAMP</code> is disabled but anytime we load a valet address (<code>mysite.dev</code>) we get a standard Apache <code>404</code> page.</p>
  
  <p>Is there a way to determine what process is listening on port 80 and conflicting with Valet so I can disable it?</p>