title: Search unique values between 2 txt files
body: <p>I have got 2 TXT files :</p>
  
  <pre><code>$file 1
  
  water
  bottle
  train
  car
  bus
  
  $file 2 
  
  coffee
  lamp
  sport
  train
  book
  </code></pre>
  
  <p>I want to get the same value present in these 2 files, in that case the result expected is "train".</p>