title: How can I generate a git diff of what's changed since the last time I pulled?
body: <p>I'd like to script, preferably in rake, the following actions into a single command:</p>
  
  <ol>
  <li>Get the version of my local git repository.</li>
  <li>Git pull the latest code.</li>
  <li>Git diff from the version I extracted in step #1 to what is now in my local repository.</li>
  </ol>
  
  <p>In other words, I want to get the latest code form the central repository and immediately generate a diff of what's changed since the last time I pulled.</p>