How to upgrade Ubuntu 12.04/12.10/13.10 to Ubuntu 14.04 Beta 2

The Beta version of Ubuntu 14.04 Beta 2 has been released. Although the official version has to wait until April 17, the changes from Beta 2 to the official version are not significant. At least till now Ubuntu 14.04 Beta 2 is the best version.

How can I upgrade from Ubuntu 12.04/12.10/13.10 to Ubuntu 14.04 Beta 2?

In fact, you only need a simple command to achieve:

First, install the Core update manager tool. If you have not installed the tool:

Sudo apt-get install update-manager-core

Then run the following command and follow the prompt in the graphic box to update it:

Sudo do-release-upgrade-d

Note: Running do-release-upgrade-d is the latest version, and the latest version is Beta 2.