title: Perl search and replace the last character occurrence
body: <p>I have what I thought would be an easy problem to solve but I am not able to find the answer to this.</p>
  
  <p>How can I find and replace the last occurrence of a character in a string?</p>
  
  <p>I have a string: GE1/0/1 and I would like it to be: GE1/0:1 &lt;- This can be variable length so no substrings please.</p>
  
  <p><strong>Clarification:</strong>
  I am looking to replace the last / with a : no matter what comes before or after it.</p>