title: log4net cross platform XML config
body: <p>I have a requirement to store my log files in a Logs sub folder. Normally you would do this my modifying the FileAppender in you App.config as follows:</p>
  
  <pre><code>&lt;file type="log4net.Util.PatternString" value="Logs\MyLog.log" /&gt;
  </code></pre>
  
  <p>However this is not cross platform because if you run this on linux it will create a file called 'Logs\MyLog.log' rather then a directory. This is because '\' is not a path separator on linux.</p>
  
  <p>We could change it to '/' but that would only work on linux and not on windows.</p>
  
  <p>How can you use the XML config for log4net to put my logs in a subfolder that works cross platform?</p>