But, alas, Ubuntu 18.04 removed Unity and replaced it with the Gnome shell. Since it introduces even more alien concepts to the desktop experience, people started to migrate to LXDE, XFCE, KDE, MATE and other environments/shells. But maybe you’re nostalgic and want Unity back. Or, maybe you’re actually one of the people that loved it for its way of doing things and feel more productive in it. These things are of course subjective. However, an objective fact is that Unity is much more fluid, faster, and responsive when compared to Gnome. Whatever your motivation may be, it’s easy to install Unity and make it the default graphical shell again.
From “main” to “universe”
All of Unity’s components were moved from “main” to the “universe” software repositories. Canonical actively maintains whatever resides in “main.” In contrast, the community maintains stuff in “universe,” meaning that volunteers update and/or improve software there – that is, if someone gets around to it and has the time and motivation to do so. This means there’s no guarantee the software will work in future generations of Ubuntu. Usually though, software packages that are popular, like this one, do get to live on either in the same form, or as some fork, under a different name, adapted to function on new versions of the operating system. So, consider this tutorial as “tested to work on Ubuntu 18.04,” and if you encounter problems on future editions, try to research if anything has changed. The first thing you should look for is whether the package name “ubuntu-unity-destkop” is the same on Ubuntu 20.04, 20.10, 22.04 and beyond. Make sure you have the “universe” repository enabled. It’s active, by default, on most installations. In that case the command will just report this and do nothing else. If it isn’t, it will enable it.
Install Unity Graphical Shell and Dependencies
Install packages and dependencies: You will get some prompts to choose the default login manager. First, you will get some generic text that explains what the choice is about, and you will only get an “OK” button to select. At the next screen, press the down arrow, select “lightdm” and press Enter.
Change Default Graphical Shell in Login Manager
Reboot your computer to reload the entire graphical stack. When you get to the login screen, click on the button highlighted in red in the next image.
You should then see what desktop environment/graphical shell will launch when the user logs in. Unity should already be the default at this point. If it isn’t it, pick it from that list. If it is, just click the back button (highlighted in red) and then log in normally.
Conclusion
That was easy, wasn’t it? And just in case you don’t like how Gnome “simplified” some programs by removing features you possibly liked, remember that you can install other programs and make your desktop even more pleasant. For example, maybe you don’t like the default file manager, Nautilus, because it looks so bare. With a simple sudo apt install caja, you can install the Caja file manager, or whatever else you prefer. Have fun making your desktop your own!