getting `pip` to use `python3` instead of macOS-supplied python2? I don't really know much about python or pip so this may be an easy question but I’ve looked around and don’t really see an easy to understand solution, and the deadline is coming up soon, so it seems like it would be a good time to get a guide together.

Recently when I was using pip I saw this warning:


  DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support


My understanding is that there is no way to upgrade the version of python provided by macOS, either in /usr/bin/python or /System/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7.

I have /usr/local/bin/python3 installed via brew but I have no idea how to tell pip to use that version of python instead of the macOS-provided version, or if that will break anything, etc.
There is no way to overwrite the existing System python(s) with newer versions. (Catalina comes with a version of python3.)

The command pip3 will specify that you want to install modules to python3. 

python2 will of course continue to work after 1st Jan, and many people still have lots of scripts that they will continue to run.