18.04desktop-environmentswindow
In ubuntu 16.04, I used Ctrl+Alt+[1-9] (on the num-keypad) to resize a window to take either the top-left, top-right, bottom-left or bottom-right corner.
In ubuntu 18.04, in Settings -> Devices -> Keyboard, I only see View split on left,right, which is good to occupy the screen with two windows. I'd like to occupy my screen with four windows without overlap.
How to resize four windows to occupy the screen without overlap on Ubuntu 18.04?
I think you can edit the EDGE settings in GRID using the CompizConfig Setting Manager
(to install this run sudo apt-get install compizconfig-settings-manager in a terminal).
If you set the corner setting (i.e setting Upper Left Corner to Top Left Corner) then when you drag the windows to the corners, it will "SNAP"
Ubuntu 18.04 dropped support for the Unity desktop compositor in favour of GNOME Shell. GNOME Shell is incompatible with Compiz. You need to look for a method to replicate this behaviour using GNOME Shell and its extensions or install and use an unofficial, community-supported version of Unity.
P.S.: There's a follow-up question with a suggestion for a replacement GNOME Shell extension.
Best Answer
There is an extension named Put Windows.
Available in Ubuntu Software. All that you need to do is install and that's it. Super + Numpad will work afterwards.
You may need to tinker with the default settings, though. It was not quite the one quarter of the screen at first for me. It was either bigger or smaller.
Update: There is also gTile which is what I use now. It is more versatile, modifiable and has more options for splitting, but you might need to do a little more tinkering setting up the hotkeys and the behavior. I found it to be much more useful, nonetheless. It also works well with multiple displays.