I've made a mistake during my fresh Ubuntu 15.04 installation as I picked the default graphical shell, the Unity flavour instead of Ubuntu Gnome 15.04, the Gnome flavour. Why so? I need to have a lean, optimized, and without much tweaking with sensible default desktop environment. I've tried Fedora 22 where Gnome 3 is the default graphical environment and had very good experience with it. Compare to Unity, it's more well-integrated and feels more cohesive.
Meanwhile, with Unity, I always have bad user experience since it was first release until now. It's quite resource intensive and buggy. If you don't have good optimized driver support for your graphic card, especially laptop, Compiz will make you cry. Yes, it's getting better these days but there still a few major annoyances with its default settings, especially that bloody freaking Unity Launcher.
My beef with Unity Launcher is the behaviour of auto-hide and the revealing sensitivity. Regardless how much I've tweak the sensitivity, out of ten times, maybe around 4 or more, whenever I moved my mouse over to the left or rather moused over the hot spot, the Launcher will not show up. Somehow the way the Launcher intercept the hot spot and its timing does not work the way as other launchers or dockers. This was made worse as there is no way to disable the auto-hide animation of the Launcher, which is perceivably slow. Not only the frustration of moving your mouse in a way within a limited hot spot to reveal the Launcher, you've to wait for it to slowly hide itself.
Let's us proceed with installation or upgrade of Gnome 3.16. But first, let's check what are the version available in the default Ubuntu Vivid repository. As shown below, default Gnome version in default repository is still version 3.14. If you want version 3.16 from default repository, you'll have to upgrade to Ubuntu 15.10.
$ apt-cache show gnome-shell | grep Version Version: 3.14.4-0ubuntu1
Before you install Gnome 3.16, you must first install version 3.14 using the default repository and purge the Unity desktop through cross-grading from Ubuntu to Ubuntu Gnome. I learned it the hard way that both desktop environments cannot coexists at the same time. Not sure why but there is a bug where you can't login to the Gnome desktop environment.
$ sudo apt-get install ubuntu-gnome-desktop $ sudo apt-get purge ubuntu-default-settings $ sudo apt-get purge ubuntu-desktop $ sudo apt-get autoremove
Once you've install Gnome 3.14 and reboot, make sure you can login through the Gnome Display Manager (GDM) successfully. Next, we proceed with upgrading by adding the Gnome 3 staging Personal Package Archives (PPA). Note that this is staging PPA, things will break, so your mileage may vary (YMMV).
$ sudo add-apt-repository ppa:gnome3-team/gnome3-staging $ sudo add-apt-repository ppa:gnome3-team/gnome3
Next, you'll need to update and dist-upgrade the system. You must use dist-upgrade command to resolve all necessary dependencies, this include removing of unused packages.
$ sudo apt-get update $ sudo apt-get dist-upgrade
Go to a terminal console by pressing Ctrl + Alt + F1 to restart the GDM manually. Alternatively, you can just reboot the system. Login again to the Gnome 3.16 desktop environment to confirm our upgrade has been successfully.
$ sudo service gdm restart
Check our Gnome version.
$ gnome-shell --version GNOME Shell 3.16.2
If you messed up the upgrade which eventually break the system (trust me it will somehow for some unknown reasons), for example, you can't see the login screen, just downgrade the Gnome 3 installation by purging Gnome 3 staging PPA. Consider the downgrade as rollback to version 3.14.
$ sudo apt-get install ppa-purge $ sudo ppa-purge ppa:gnome3-team/gnome3-staging $ sudo ppa-purge ppa:gnome3-team/gnome3
If you encounter any login issue with any desktop environments even through you've successfully logged in before, you'll need to remove the .Xauthority file. Go to the virtual console (Ctrl + Alt + F1), login using the same account credential and delete the .Xauthority file. Logout and switch to the graphical virtual console (Ctrl + Alt + F7) and try to login again.
$ rm -rf .Xauthority