Any good information on HOW ENVIRONMENTS work in / on Ubuntu?

Question

I'm currently learning (really early stages) of Ubuntu.

I've learned so far that Ubuntu can be run with other environments on it. Could you guys please provide info (links or descriptions) on HOW THIS WORKS and HOW many I can Run over Ubuntu? I know these are 3 questions in 1 but also, would the environments to be installed have to be updated (or the same version) of the Ubuntu installed already?

I've found links here on WHAT environment works and the beauty of using them but I can't seem to find the answer to my questions.

P.S. I'm no looking for a long list of environments or a long explanation just a mild list or summary.

Answer 1

You can install as many as you want to on a single version of ubuntu. You choose which one you want to use when you log in. Sometimes, installing kde (kubuntu) along with other environments can mess up your themes in other environments but other than that it's no problem. It's best to stick to one but you may want to have multiple ones to choose from until you decide which one you like best.

It also helps to have a barebones desktop like openbox or fluxbox to choose from when you need to run an application that uses alot of resources so you can get the best performance.

You can also dualboot (tripleboot etc) more than one ubuntu on your computer.

Answer 2

Here's a little more in-depth overview:

Unix-like systems are traditionally build with console only, and historically they were so from the beginning until developers came up with graphical interface. Particularly , there must be a graphical server (think of it as a program/software ). So in the old days you'd go to console, log in, and run startx command to start that graphical server (in fact it's called the X server or X11, hence startx naming for the command ). Nowadays, there are other servers than X, particularly there's Wayland graphical server and X server derivatives. The first graphical environment would be motif , or mwm , which I use occasionally. Now, if you run startx you'd get simply the default environment that you have set for your user. If you'd want something else, you'd run startx /usr/bin/gnome-shell for instance.

As you can see this approach is somewhat cumbersome, so over the years developers came up with graphical login screens. In the Linux world they are commonly known as display managers or greeters. For instance, the default login screen for Ubuntu would be lightdm. This sofware decides which environment to give for a particular user. On that same login screen, you'd chose an alternative environment which are installed on your system.

Can a user install multiple environments ? Yes. On my machine I have gnome,openbox,blackbox,icewm,mwm, and unity. Can two different environments be ran at the same time ? Yes. I occasionally run gnome-shell as logged in from the graphical login screen, and openbox on tty1 console with that same startx command mentioned above. An instance of x server works the same way as if you'd run multiple instances of any other software, and each instance shares control over screen and keyboard at a time - when one is active, the other just waits in the background for the user to give control over keyboard and screen to it.

There's tons of benefit for running multiple GUI environments, actually. If something breaks after an update, for instance Unity doesn't start , you can always hop into Gnome and continue working.