Changing the version of python to ubuntu broke everything, how to fix it?

Question

linux

Good afternoon, on the operating system there was a version of python 3.8.10, I installed 3.9.7 and switched to a newer one with the following commands

sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.8 1
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.9 2

After that, the terminal stopped starting, and many other jambs appeared in the OS.

How to upgrade to a newer version of python?

Answer 1

Don't do that - you'll end up in dependencies hell
Use pyenv (don't forget to install libraries ).
To install pyenv curl https://pyenv.run | bash
Install Python pyenv install 3.9.7
Make it the default interpreter pyenv global 3.9.7, but you don't have to do that either, but you need to create virualenv and work in it.
And there is a win-win option - run in Docker.

Answer 2

Open virtual Console( Ctrl+Alt+F1 or something like that) and put everything back. Or boot into safe mode and return everything back.

Answer 3

The question is, where did you get the idea that those applications that broke are compatible with version 3.9? I don't know how things are in python with backward compatibility, but the libraries on which certain functions were tied in applications may not be backward compatible between 3.9 and 3.8, which is where everything broke. The "correct" transition may simply not exist.