I found a one-liner which can uninstall all pip packages:
pip3 freeze | grep -v "^-e" | xargs sudo pip3 uninstall -y
I used to do the following:
pip3 freeze > reqs.txt
sudo pip3 uninstall -r reqs.txt
I didn’t realise I could do pip uninstall -r reqs.txt -y and get rid of those confirmation questions. And I’m pretty sure I messed up the actual requirements file at least once when adopting this approach.
The one-liner for the two commands (without messing up the real file) is:
sudo pip3 uninstall -y -r < (pip3 freeze)
Many thanks to the Stack Overflow community.