title: How to extract some missing rows by comparing two different files in linux?
body: <p>I have two diferrent files which some rows are missing in one of the files. I want to make a new file including those non-common rows between two files. as and example, I have following files:</p>
  
  <p>file1:</p>
  
  <pre><code>id1 
  id22 
  id3 
  id4 
  id43 
  id100 
  id433 
  </code></pre>
  
  <p>file2:</p>
  
  <pre><code>id1
  id2
  id22
  id3
  id4
  id8
  id43
  id100
  id433
  id21
  </code></pre>
  
  <p>I want to extract those rows which exist in file2 but do not in file1:</p>
  
  <p>new file:</p>
  
  <pre><code> id2
   id8 
   id21
  </code></pre>
  
  <p>any suggestion please?</p>