title: Replace Column if equal to a specific value
body: <p>I'm looking to replace the fourth column in a CSV if it equals <code>N/A</code>.  I'm trying to change it to <code>-1</code>.<br>  I can't seem to get this to work.</p>
  
  <pre><code>awk -F , '{ if($4 == "N/A") {$4 = -1} }' test.csv
  </code></pre>