How to check all versions of python installed on osx and centos

Question

I just started setting up a centos server today and noticed that the default version of python on centos is set to 2.6.6. I want to use python 2.7 instead. I googled around and

Answer 1

COMMAND: python --version && python3 --version

OUTPUT:

Python 2.7.10
Python 3.7.1

ALIAS COMMAND: pyver

OUTPUT:

Python 2.7.10
Python 3.7.1

You can make an alias like "pyver" in your .bashrc file or else using a text accelerator like AText maybe.