title: compare if two columns of a file is identiical in linux
body: <p>I would like to compare if two columns (mid) in a file is identical to each other. I am not sure of how to do it...Since the original file that I am working one is rather huge (in Gb)</p>
  
  <p>file 1 (column1 and column 4 - to check if they are identical)</p>
  
  <pre><code>mid A1  A2  mid A3  A4  A5  A6
  18  we  gf  18  32  23  45  89
  19  ew  fg  19  33  24  46  90
  21  ew  fg  21  35  26  48  92
  </code></pre>
  
  <p>Thanks
  M</p>