title: UpperCase Hostname in Log4j
body: <p>Good morning.
  I have a problem to UpperCase the name of a file with the hostname. I'm trying to configure with this:</p>
  <pre><code>&lt;Property name=&quot;example&quot;&gt;$$upper{${hostName}}&lt;/Property&gt;
  ...
  &lt;RollingFile name=&quot;RA.FileAppender&quot; fileName=&quot;${example}_%d{yyMMdd}.log&quot; filePattern=&quot;${example}_%d{yyMMdd}_%02i.log.gz&quot;&gt;
  </code></pre>
  <p>But this doesn't work. This is the name of file</p>
  <p>$$upper{RealHostName}_%d{yyMMdd}.log</p>
  <p>How can does this work?
  Thanks and regards</p>