title: Detail change after Git pull
body: <p>After a Git pull, its output gives a summary on the change amount.</p>
  
  <p>How can I see each or some of the files detailed changes?</p>
  
  <p>Okay, here is my question to Jefromi:</p>
  
  <ol>
  <li><p>How do I know if I was pulling to master? All I did is "git pull".</p></li>
  <li><p>What does master point to and what is the difference between master and HEAD, the two default heads of Git?</p></li>
  <li><p>How do I see the detailed change in a specific file?</p></li>
  <li><p>How do I see the change in the summary output by the last <code>git pull</code> again?</p></li>
  <li><p>What's difference between <code>git diff</code> and <code>git whatchanged</code>?</p></li>
  </ol>