When do I run "apt-get update" on Ubuntu 18.04 LTS? Is it ever necessary under Long Term Support?
After reading the suggested duplicates I don't believe my question is a duplicate. I already know what apt-get update does, but that wasn't my question.
If you have set System settings (icon in the Launcher) > Software and updates > / Updates \ > Automatically check for updates: to something else than "Never", then you shouldn't need to do anything from the command line.
$ sudo apt-get update will launch a process to check for available updates "now".
$ sudo apt-get upgrade will install the updates based on what was found.
$ sudo apt-get dist-upgrade simplified: if any packages were "held back" during the upgrade, this will install them.
For upgrade and dist-upgrade, and also anything install, remove or purge:
Do check thoroughly what it says before actually letting it to do its thing.
There MIGHT be surprises.
Links worth a look:
What does "sudo apt-get update" do?
https://askubuntu.com/a/694412/22949
dist-upgrade might not install all upgrades. Sometimes the reason why an upgrade is not installed by upgrade is that it cannot be installed, full stop (a common cause is an unsatisfiable dependency).
– fkraiem
Jul 25 '19 at 15:28
To answer your question quickly; right after a fresh install of the operating system, before installing software, after adding new repositories to install software, and as often as possible.
