How To Update All Python Packages

The pip package manager can be used to update one or more packages system-wide: in this short note we will see how to proceed.
To generate a list of all outdated packages:

pip list --outdated

To upgrade all packages using pip with grep:

pip3 list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1 | xargs -n1 pip3 install -U