One of the positive things about Ubuntu and Gnu / Linux is the strong customization that it has of the operating system compared to others like Windows, which hardly allows customizing the operating system. So in Ubuntu we can customize even the key combinations of the Operating System, something that can be useful to more than one user.
These key combinations and commands can be predefined or changed however we want or it is easier for us. This is useful if, for example, we have problems with our keyboard or we have a broken key, it will also allow us to open everything using key combinations and forget about using the mouse. Currently in Ubuntu there are three methods to change or alter the key combinations. Two of them are easy while the other is a method for somewhat advanced users. In this case the easiest method is by the installation of the Keytouch program that allows us to modify everything graphically. In this link You can find more information about the application.
Key combinations can be useful for when the mouse is not working
The second method is more difficult but it really works, it is done through the editor GConf-Editor. In this editor we address apps / metacity / keybinding_commands and there we will see a list of 12 commands that we can alter to our liking. In apps / metacity / global_keybindings we will find other different functions but they will complement the other commands.
The third method is the one that everyone will know and surely have already manipulated. In System Settings–> Preferences–> Key Combinations, any Ubuntu user will be able to change and alter the system key combinations, but only to a limited extent.
If you really want to have a strong customization of the operating system, that is, of our Ubuntu, I would use all systems, since there are commands that do not appear in System Settings but that KeyTouch can alter and other commands that can only be performed through GConf-Editor. Hence the three systems. But if you do not want to customize a lot, the safest option may be the simple methods Do not you think?