How to upgrade ubuntu 12.4 to 14.4

Question

I bought a new Dell 3542 laptop with Ubuntu 12.04. I want to upgrade it to 14.04. My update manager is showing there are no updates to install. Please tell me step by step how to upgrade. Thank you.

Answer 1

Open a terminal window and

sudo do-release-upgrade

If you are doing the upgrade over SSH it will spawn a new SSH daemon and warn you that you may lose connectivity during the upgrade and tell you how to reconnect.

It's always best to do it locally if you can, but I've done many over SSH connections :)

Answer 2

Install the update-manager-core package:

 apt-get install update-manager-core

Open the release-upgrades file for editing by entering the following command:

 nano /etc/update-manager/release-upgrades

Verify that the following line is present in the file, and that Prompt is set to lts:

Prompt=lts

Exit nano and upgrade your Linode to Ubuntu 14.04 LTS by entering the following command:

do-release-upgrade -d

Follow the on-screen instructions to complete the installation process. You will be prompted as to whether you wish to continue; as you are on LISH, it is safe to continue via SSH.

You may see a message type y and hit enter

Verify that it’s running Ubuntu 14.04 LTS by entering the following command:

cat /etc/lsb-release

Answer 3

You can do this following To upgrade on a desktop system:

Press Ctrl +Alt+T(to open a terminal) and type in sudo update-manager

Update Manager should open up and tell you: New distribution release '14.04 LTS' is available. I can show a windows in my case(i am already on 14.04 LTS so it will be different for you) Click Upgrade and follow the on-screen instructions.

For more info, visit here

Answer 4

I would comment Ashu's answer, but I don't have the reputation for that, so I post another answer.

Open update-manager and click Settings.

As Rinzwind commented at your question, remember to enable long-term support versions at software-sources settings.

Then follow Ashu's instructions.

Have in your mind that some of us (Pilot6 also) prefere not to upgrade distributions this way, but doing a clean install. You can do it better if you prepare a boot-USB before possibly mess-up your 12.04 system upgrading it to 14.04, using start-up disk creator and a proper for your laptop 14.04 ISO, downloaded from http://releases.ubuntu.com/14.04/.