title: PHP "or" Syntax
body: <p>I've seen this a lot: <code>$fp = fopen($filepath, "w") or die();</code>
  But I can't seem to find any real documentation on this "or" syntax. It's obvious enough what it does, but can I use it anywhere? And must it be followed by <code>die()</code>? Are there any caveats to using <code>or</code> when you could use something like</p>
  
  <pre><code>if (file_exists($filepath))
     $fp = fopen($filepath,"r");
  else
     myErrMessage();
  </code></pre>
  
  <p>I know it seems like a silly question, but I can't find any hard and fast rules for this. Thanks.</p>