Although learning each and every keyboard shortcut on Linux may be challenging, with a bit of practice you could significantly increase your personal productivity and speed while learning some of the common ones, like below:

1. Ctrl + Alt + Backspace
Helpful shortcut that is used when X isn’t responding or a program has locked up your desktop and is unresponsive. This combination logs you out of X and takes you back to the login screen.

2. Ctrl + Alt + Delete
Use this shortcut if you need to reboot when all access to the desktop is frozen. All unsaved data will be lost when executing this combination.

3. Alt + Tab
You can use this shortcut to cycle through all open windows without needing the mouse. Browse through them by holding down the ALT key and press Tab until it lands on the window you want.

4. Ctrl + Alt + F*
This shortcut helps switch to various virtual terminals almost seamlessly. The default terminal you’re working in is 6. So you can switch to another terminal by holding down Ctrl + Alt and hitting F1, F2, F3, F4, F5, F7, etc. Quite a helpful combination for debugging problems with the desktop or eliminating frozen applications.

5. Alt + Arrow key
Thanks to the pager within Linux, you can have multiple desktops simultaneously. This shortcut can help you move from one desktop to another without using the mouse.

6. Ctrl + C
You can quickly eliminate a process in the terminal window with this combination.

7. Ctrl + Z
You can easily send a running process to the background without stopping the application by using this combination from the terminal.