Change the default Linux is Python3 Python2

Original link: https://blog.csdn.net/qq_38742266/article/details/80838205

Both commands can be executed directly:

sudo update-alternatives --install /usr/bin/python python /usr/bin/python2 100
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 150

If you want to switch to Python2, execute:

sudo update-alternatives --config python