title: Delete lines based on another file
body: <p>I have a unix question similar to one that is being asked here</p>
  
  <p><a href="https://stackoverflow.com/questions/16477782/delete-lines-based-on-pattern-on-another-file">Delete lines based on pattern on another file</a></p>
  
  <p>I have file1.txt whose contents are</p>
  
  <pre><code>part1
  part2
  part3
  part4
  </code></pre>
  
  <p>I have another file2.txt whose content are (it has 2000 lines)</p>
  
  <pre><code>part1
  part2
  part3
  ...
  part2000
  </code></pre>
  
  <p>I would like to remove all lines from file2.txt that match contents of file1.txt. I tried the solution in as suggested in the above post but those tags are not available for me on my SUN Unix server.</p>
  
  <pre><code>% grep -Fvf file1.txt file2.txt &gt; output.txt
  grep: illegal option -- F
  grep: illegal option -- f
  Usage: grep -hblcnsviw pattern file . . .
  </code></pre>