title: Specify user's home directory in a .properties file
body: <p>I am trying to integrate p6spy (3.x.x) in my project, and in <code>spy.properties</code> file, I wanted to specify</p>
  
  <pre><code>logfile=${user.home}/logs/spy-%d{yyyyMMdd}.log
  </code></pre>
  
  <p>or at least</p>
  
  <pre><code>logfile=${user.home}/logs/spy.log 
  </code></pre>
  
  <p>So far, I couldn't manage to do either, and the execution is failing with <code>FileNotFoundException</code></p>
  
  <pre><code>java.io.FileNotFoundException: ${user.home}/logs/spy.log (No such file or directory) 
  </code></pre>
  
  <p>Mine is a Spring Boot project with collaborators running different operating systems. By default, it is creating the <code>spy.log</code> file in project root, which is not good.</p>
  
  <p>Is it possible to specify relative paths like the way I want in .properties files? If yes, how?</p>
  
  <p>Thanks a lot!</p>