title: awk + print the second field in line only if the four field is 0
body: <p>How to print $2 by awk only if the fourth field is not 0 (zero).</p>
  
  <pre><code>line="root     13246 11314  457 15: qsRw -m1"
  </code></pre>
  
  <p>then awk will print 13246, but if </p>
  
  <pre><code>line="root     13246 11314  0 15: qsRw -m1"
  </code></pre>
  
  <p>then awk will not print anything</p>