title: How to detect if the script is running on a virtual machine?
body: <p>I don't think the question needs any explanation.
  I'm writing a software that can boot virtual machines to simulate a network. I would like to disable this feature if the software is already running on a virtual machine.</p>
  
  <p>I already read this post: <a href="https://stackoverflow.com/questions/498371/how-to-detect-if-my-application-is-running-in-a-virtual-machine">How to detect if my application is running in a virtual machine?</a>
  But I need to do it on Linux and that post covers only Windows.</p>
  
  <p>I'm tagging it as a <code>Perl</code> question as I've to do it in Perl, but probably there are some file in <code>proc</code> or somewhere else to check and it's the same for all languages. I don't know actually.</p>
  
  <p>I'm interested in detecting mainly VirtualBox and KVM, as those are the VMs I'm using.</p>
  
  <p>So, any suggestion?</p>