From https://github.com/pypa/python-packaging-user-guide/issues/406 , A better answer to your question about installing tools system wide seems to be 'pipsi'.
https://pypi.org/project/pipsi/ pipsi = pip script installer What does it do? pipsi is a wrapper around virtualenv and pip which installs scripts provided by python packages into separate virtualenvs to shield them from your system and each other.
