Self-tutoring about Ubuntu Linux: the tutor mentions command-line update.
I resurrected a computer that likely hadn’t run in 8 years (or longer) using Lubuntu. It identifies, from the terminal, as Ubuntu 18.04.
I tried updating its software from the GUI but no luck: I decided to try from the terminal. Specifically, I typed in
sudo apt update
then gave the password. After it finished finding the updates, I typed in
sudo apt upgrade
It was a success, though the updates took quite some time to process.
Source:Oracle Tutoring by Jack and Diane, Campbell River, BC.