Ubuntu

Ubuntu is a Linux distribution based on Debian and developed by Canonical.

Official documentation can be found at https://help.ubuntu.com/.

Ubuntu Desktop

Installation

Use the Official Ubuntu Documentation page to find the official installation guide for the version and platform you desire to install. For example, the installation guide for 18.04 of amd64 is here.

Ubuntu Server

Server documentation: https://ubuntu.com/server/docs

Netplan documentation: https://netplan.io/

Kubuntu

Installation

See Kubuntu Help and Support. Download and use the PDF for the desired version.

Disabling auto update

APT::Periodic::Update-Package-Lists "0";
APT::Periodic::Unattended-Upgrade "0";

Package Management

Switching version of major packages

Use update-alternatives --config java 

Fixing broken packages

Sometime you will get an error like: E: Unable to correct problems, you have held broken packages. 

To solve, you can try installing aptitude  and trying aptitude install <package> 

The aptitude utility has more powerful conflict resolution abilities.

See issue: https://askubuntu.com/a/451078

Listing installed packages

apt list --installed > installed.txt 

Open and Ctrl+F in text editor

Upgrading Ubuntu

First, fully upgrade your existing installation:

# apt update
# apt upgrade

# apt remove ros-*
# apt autoremove
# rm /etc/apt/sources.list.d/ros-latest.list
# apt update

Finally, remove unneeded stuff, reboot to make sure the system still boots, then do the release upgrade:

# apt autoremove
# reboot
# apt do-release-upgrade

Troubleshooting

If something happens and you lose the terminal, try the steps at https://serverfault.com/a/427008.

ssh <machine you're upgrading>
# screen -list
# screen -d -r root/2953.ubuntu-release-upgrade-screen-window