title: How can I find repeated letters with a Perl regex?
body: <p>I am looking for a regex that will find repeating letters. So any letter twice or more, for example:</p>
  
  <pre><code>booooooot or abbott
  </code></pre>
  
  <p>I won't know the letter I am looking for ahead of time. </p>
  
  <p>This is a question I was asked in interviews and then asked in interviews. Not so many people get it correct.</p>