Install Python 2 for Ubuntu 21.10

First

install python2

sudo apt install python2

Check the... Available on the system Python edition ：

ls /usr/bin/python* 

See if... Is configured Python Alternative version scheme , The order is as follows ：

sudo update-alternatives --list python

Set up python Alternate version

ad locum , I will set up two Python replace :Python2 and Python3 edition .

sudo update-alternatives --install /usr/bin/python python /usr/bin/python2 1
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 2

Confirm that both alternatives can be used , The order is as follows ：

sudo update-alternatives --list python

Next select the optional Python edition .

sudo update-alternatives --config python

Enter your selection , For example, choose 1 To determine the installation python2 edition .

Last , Check your python edition

python -V