title: Awk regex for a string of exact length that ends in ":"
body: <p>I just can't get the regex right:</p>
  
  <pre><code>awk '$6 ~ /:${14}/ {print $6}' file
  </code></pre>
  
  <p>I need to print out the 6th field if it's 15 characters long and ends with a ":".</p>
  
  <p>Here's an example: <code>oAFKq7XS001224:</code></p>