title: Back to revision in Subversion
body: <p>suppose you update your code to revision 10 which is broken. You want to go back to revision 9, work on the code and wait until someone will fix the build:</p>
  
  <pre><code>svn merge -rHEAD:9 .
  </code></pre>
  
  <p>But it won't work, why?</p>