Imagine that one did not realize how virtual environments work in Python and installed a lot of packages using sudo pip install for OS:X. Now they are facing problems managing package versions.
This would never happen if one understands virtual environments, but if one did this prior to being enlightened, how can that someone easily remove all my their non-virtual environment packages that were installed, without breaking any default installations?
Note this includes several programs (such as nosetests) and is not limited to exclusively libraries. It seems I can create a virtualenvironment with --no-site-packages and that gets around at least the packages (assuming I wipe my PYTHONPATH). But my actual PATH seems to let me see the executables I installed, too.