title: How to output difference between two text files?
body: <p>I'm wondering how I can compare two text files, highlighting the difference between each of them? For example:</p>
  
  <p>File1.txt</p>
  
  <pre><code>AAAAA
  BBBBB
  CCCCC
  </code></pre>
  
  <p>File2.txt</p>
  
  <pre><code>AAAAA
  BBBBB
  </code></pre>
  
  <p>I'd like to have the following output after comparison of those two files:</p>
  
  <pre><code>CCCCC
  </code></pre>
  
  <p>I'm using Python, and tried sed and grep with no luck (I'm interested in linux shell ways of doing this too).</p>