老版本的ubuntu安装python 3.8

参考：https://devpress.csdn.net/python/6304562fc67703293080b643.html

sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt update
sudo apt install python3.8

 

sudo apt install python3.8-pip

参考:https://www.cnblogs.com/ace722/p/9697331.html