title: How to create a virtualenv by cloning the current local environment?
body: <p>Suppose I have a python interpreter with many modules installed on my local system, and it has been tuned to just work. </p>
  
  <p>Now I want to create a virtualenv to freeze these, so that they won't be broke by upgrading in the future. </p>
  
  <p>How can I make it? Thanks.</p>
  
  <hr>
  
  <p>I can't use <code>pip freeze</code>, because that's a cluster on which there's no <code>pip</code> and I don't have the privileges to install it. And I don't want the reinstall the modules either, I'm looking for that whether there's a cloning way.</p>