title: Confusion about mac find command man page
body: <p>While in the <code>find</code> manual page, the Synopsis part says:</p>
  
  <pre><code>SYNOPSIS
  
   find [-H | -L | -P] [-EXdsx]
        [-f path] path ...
        [expression]
  </code></pre>
  
  <p>And i want to find all files whose name contains "optimizing" in the current directory, so i go with this command:</p>
  
  <pre><code>find -E -f . -iregex ".*optimizing.*"
  </code></pre>
  
  <p>I think this match the synopsis requirements, <code>-E</code> for <code>extended regex</code>, <code>-f .</code> for <code>[-f path]</code> part
  But the output says:</p>
  
  <pre><code>find: -f .: unknown primary or operator
  </code></pre>
  
  <p>But if i remove the <code>-f</code> options, and run this: <code>find -E . -iregex ".*optimizing.*"</code>. It would run as expected.</p>
  
  <p>And dose the <code>SYNOPSIS</code> part followed the regex grammar? That is, dose <code>[-EXdsx]</code> means i can use any character in <code>-EXdsx</code> in that part?</p>
  
  <p>These really confused me, and make reading man page a really horrible thing for me.</p>
  
  <p>Any help would be appreciated!</p>