title: Automatically cleanup tmp directory in Unix
body: <p>I am implementing my own file cache server using Play framework, and I put my cached files in <code>/tmp</code> directory.</p>
  
  <p>However I do not know how the OS manages the <code>/tmp</code> directory. What I wish to know is if the OS will automatically cleanup some files that are old enough, or have not been accessed for a long time.</p>
  
  <p>I am running my server in a Docker container, based on Debian jessie.</p>