title: Filter column with awk and regexp
body: <p>I've a pretty simple question. I've a file containing several columns and I want to filter them using awk.</p>
  
  <p>So the column of interest is the 6th column and I want to find every string containing :</p>
  
  <ul>
  <li>starting with a number from 1 to 100</li>
  <li>after that one "S" or a "M"</li>
  <li>again a number from 1 to 100</li>
  <li>after that one "S" or a "M"</li>
  </ul>
  
  <p>So per example : 20S50M is ok</p>
  
  <p>I tried :</p>
  
  <pre><code>awk '{ if($6 == '/[1-100][S|M][1-100][S|M]/') print} file.txt
  </code></pre>
  
  <p>but it didn't work... What am I doing wrong?</p>