title: Print only if field is not empty
body: <p>I have a text file that I want to pull host and IP info from only if the IP exists in column 4.  For example:</p>
  
  <pre><code>cat hostlist.txt
  Server One 255.255.255.255 123.123.123.123
  Server Two 255.255.255.255 
  Server Three 255.255.255.255 123.123.123.123
  </code></pre>
  
  <p>In this case I would only want to see Server One and Three as Server Two has no data in the fourth column.</p>