alternative is a useful program that allows you to switch between different versions of the same program
example: when I run python, I can change between the default python version by:
# alternatives --install /usr/bin/python python /usr/bin/python2.7 1
# alternatives --install /usr/bin/python python /usr/bin/python3.7 2
#switch between the two
sudo alternatives --config python
https://fedoraproject.org/wiki/Alternatives_system
https://medium.com/coderlist/how-to-change-default-python-version-on-linux-fedora-28-c22da18bdd6