title: ERROR: While executing gem ... (Errno::EPERM) Operation not permitted
body: <p>I just updated my Mac to OSX 10.11 El Capitan and some gems didn't remain.</p>
  
  <p>The problem arose when I tried to run installations of different gems... e.g.:</p>
  
  <pre><code>&gt; sudo gem install compass
  </code></pre>
  
  <p>Once I execute, I get the error:</p>
  
  <pre><code>&gt; ERROR:  While executing gem ... (Errno::EPERM) Operation not permitted
  </code></pre>
  
  <p>This happens with other gems, as well...</p>
  
  <p>I've run Homebrew and tried to install Ruby again, but nothing is working.</p>