title: How to diff changed files versus previous versions after a pull?
body: <p>When I run "git pull" I often want to know what changed between the last version of a file and the new one.  Say I want to know what someone else committed to a particular file.</p>
  
  <p>How is that done?</p>
  
  <p>I'm assuming it's "git diff" with some parameters for commit x versus commit y but I can't seem to get the syntax.  I also find "git log" confusing a bit and am not sure where to get the commit ID of my latest version of the file versus the new one.</p>