title: Only trigger a build on commits to the trunk with svn
body: <p>I have just set up a post-commit script in our subversion repository that triggers a build by requesting a hudson build URL.</p>
  
  <p>This works fine as expected, however now I only want to trigger this build if the commit was to the trunk.</p>
  
  <p>our post-commit script looks like this:</p>
  
  <pre><code>SET REPOS=%1
  SET REV=%2
  
  SET DIR=%REPOS%/hooks
  SET PATH=%PATH%;%DIR%
  wget http://circus-09:8080/job/UE/build?delay=0sec
  </code></pre>
  
  <p>How to I check that the commit was to the trunk?</p>