title: How to use system environment variables in log4j.properties?
body: <p>I added the system environment value
  PROJECT_HOME=C:\Program Files\Project </p>
  
  <p>Now i'm trying to use the system environment value in log4j.properties but didn't set it </p>
  
  <pre><code>**log4j.properties**
  **log4j.appender.LOGFILE.File="${env.PROJECT_HOME}"/project.log**
  </code></pre>
  
  <p>Could you please tell me how to set system environment variables in log4j.properties?</p>
  
  <p><strong>Using log4j-1.2.7 version</strong></p>