title: Difference between Revert and Update in Mercurial
body: <p>I'm just getting started with Mercurial, and I've come across something which I don't understand.</p>
  
  <p>I made changes to several files, and now I want to undo all the changes I made to one of them (i.e. go back to my last commit for one specific file).</p>
  
  <p>As far as I can see, the command I want is <a href="https://www.mercurial-scm.org/wiki/Revert" rel="nofollow noreferrer">revert</a>.</p>
  
  <p>In the page I linked to, there is the following statement:</p>
  
  <blockquote>
    <p>This operation however does not change
    the parent revision of the working
    directory (or revisions in case of an
    uncommitted merge). To undo an
    uncomitted merge, you can use "hg
    update -C -r." which will reset the
    parents to the first parent.</p>
  </blockquote>
  
  <p>I don't understand the difference between the two (<code>hg revert</code> vs. <code>hg update -C -r</code>). Can anyone enlighten me as to the difference? And in my case, do I really want the revert or the update to go get rid of the changes I made to the file?</p>