title: Grep Pattern Repetition
body: <p>I have a csv (comma separated file). I would like to know how to search for a pattern where the 7th and 8th field are the same using only grep (no using <code>cut</code>). I have tried something like this:</p>
  
  <pre><code>grep -E '[^,]*,{6,6}' input.csv | grep '\(.*\)\(,\)\(\1$\)' | less
  </code></pre>
  
  <p>Unfortunately, this does not print anything. How could I get the output I need?</p>