title: .bat file to compare two text files and output the difference
body: <p>I am trying something new that I have done on UNIX successfully but have no idea how to do on windows.</p>
  
  <p>So I save a text file, let's say test1.txt and 12 hours later compare the test2.txt (which is test1.txt with changes added during the 12 hours, almost guaranteed to be at the end of the file) to test1.txt and then output just the text differences to a third file, diff.txt </p>
  
  <pre><code>1 action
  2 action
  3 action
  4 action 
  5 action
  </code></pre>
  
  <p>and test2.txt looks like </p>
  
  <pre><code>1 action
  2 action
  3 action
  4 action 
  5 action
  6 action
  7 action
  8 action
  </code></pre>
  
  <p>then the output to the third file diff.txt would look like:</p>
  
  <pre><code>6 action
  7 action
  8 action
  </code></pre>
  
  <p>with just the text that has been added, no info regarding lines or comparisons,just a basic output of the differences.</p>
  
  <p>I am COMPLETELY new to this, have looked around and it seems I can write a batch file (.bat) that will basically just act as a UNIX script would.</p>
  
  <p>Sorry for my basic question but I've googled the question and can't seem to figure it out.</p>