title: Negative regex for Perl string pattern match
body: <p>I have this regex:</p>
  
  <pre><code>if($string =~ m/^(Clinton|[^Bush]|Reagan)/i)
    {print "$string\n"};
  </code></pre>
  
  <p>I want to match with Clinton and Reagan, but not Bush.</p>
  
  <p>It's not working.</p>