https://www.lsjlt.com/news/375465.html
#use this command to update the system version from 18.04 to 20.04
#just follow the tutorial, and click 'yes' and 'keep version' etc..
#the first selection the system auto presents
#it takes 1h 30mim nearly
sudo do-release-upgrade
#use this command again update from 20.04 to 22.04
sudo do-release-upgrade
标签:use,upgrade,version,sudo,system,22.04,ubuntu18.04,20.04
From: https://blog.51cto.com/u_15389271/7642683