Ubuntu LTS Upgrade

When you have backed up your data and ready to upgrade, from current Ubuntu LTS version (e.g. 16.04) to next (e.g. 18.04), following could be useful:

Find the current version of Ubuntu using:

lsb_release -a

Following commands make sure that you have update manager installed, your software sources are up-to-date and your current OS is updated to the newest version:

sudo apt-get install update-manager-core

sudo apt-get update

sudo do-release-upgrade

To get the development version, using -d switch, like so:

sudo do-release-upgrade -d

Source:

How to upgrade Ubuntu (Mate) via the terminalHi all, this is for anyone who wants to use the terminal to fully update their current installed OS to the next available version, you just need to follow the next few steps and you can update directly without using the on-board update tool (Software Updater). First, make sure that your current software sources are set to your liking, making sure that the "Canonical" repositories are also active if you wish to also update any non-free software you might have installed such as Skype. Make s...