title: How to properly make a copy of a Python environment
body: <p>I have multiple python installs on a network drive (2.6, 2.7 each in 32 and 64 bits). I wanna update/delete/install packages on one of them but I wanna test if it doesn't break anything before putting my changes in production. So I made a copy of, let's say, Python 2.7 64 bits and started modifying packages with pip. Only to notice a few minutes later that the pip from the copied folder I was using was still pointing to the python install I copied it from. How can I make it point to the new folder?</p>
  
  <p>After that I also tried using a virtualenv but some of the packages in production are a bit old and some of them could not be found on PyPi so doing a pip freeze in a requirements.txt then trying to install from it didn't work pretty well. Also i'm gonna have the same issue in the other way.</p>