It means that your user-site-packages directory is not on the PATH. Pip doesn't modify the system PATH variable. The site-packages directory, where scripts are installed by default, is normally added to PATH by the Python installer during installation. If for whatever reason this is not the case on your system you can add this manually.
pip show pythononwheelsExample from an Ubuntu 18.04 System:
Name: pythononwheels
Version: 0.912
Summary: The simple, quick and easy generative web framework for python
Home-page: http://www.pythononwheels.org
Author: khz
Author-email: khz@tzi.org
License: MIT
Location: /home/khz/.local/lib/python3.6/site-packages
Requires: tornado
This means the package is installed in /home/khz/.local/lib/python3.6/site-packages
export PATH=$PATH:~/.local/bin Even more info on that: