title: search empty value in awk
body: <p>I have a txt file which has many columns whcih are pipe delimited. I want to check if column <code>$36</code> is '0', null or blank then filter the whole row.</p>
  
  <pre><code>awk -F"|" 'BEGIN{OFS="|"} NR!=1, $3="A" &amp;&amp; $36!=0 &amp;&amp; length($36)&gt;0
  {print $1, $81, $3, $2, $21, $22, $6, $19, $20, $25, $26, $29, $30,
  $31, $33, $34, $36, $38, "", $39, "", "", $40, $42, "rrr", "", "" }'
  </code></pre>
  
  <p>I tried using <code>length($36)&gt;0</code> but its not working for blank values. I can see the file the column is like this <code>||</code>(two pipes nothing in between).</p>
  
  <p>Please help me to identify these values and apply the filter.</p>