title: svn : how to create a branch from certain revision of trunk
body: <p>The following action will only create a branch from the head revision of the trunk. How do I  create a branch from a specific revision? Thanks.</p>
  
  <pre><code>$ svn copy http://svn.example.com/repos/calc/trunk \
         http://svn.example.com/repos/calc/branches/my-calc-branch \
    -m "Creating a private branch of /calc/trunk."
  </code></pre>