title: grep invert match on two files
body: <p>I have two text files containing one column each, for example -</p>
  
  <p>File_A &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; File_B</p>
  
  <p>1 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1</p>
  
  <p>2 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 2</p>
  
  <p>3 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 8</p>
  
  <p>If I do <code>grep -f File_A File_B &gt; File_C</code>, I get File_C containing 1 and 2. I want to know how to use grep -v on two files so that I can get the non-matching values, 3 and 8 in the above example.</p>
  
  <p>Thanks.</p>