Understanding Linux Runlevels

In this article, I would like to take some notes on something called "runmode" in Linux.

What is runmode?

Runmode is used when you want to use Linux in a CUI (Command Line Interface), even though most people might typically use it with a GUI.
As the name "mode" suggests, there are several modes available.

Mode	Name	Description
0	Shutdown	Power off
1	Single User Mode	Assumes only one user; always an administrator
2	Multi-user Mode (no net)	Apparently not usually distinguished from 3.
3	Multi-user Mode (with net)	The usual setup where sudo is required for operations needing admin privileges.
4	Reserved	This is a reserved slot. (I accidentally typed "Yuyaku")
5	GUI	The usual GUI Linux.
6	Reboot	This is for rebooting.

Use Cases

For example, you can turn a laptop you use every day into a temporary server, or you could install a GUI-based OS because you might use the GUI once in a while, but primarily operate it in CUI mode.

Actual Change Methods

Manjaro Linux

sudo systemctl isolate graphical.target # Switch to GUI.
sudo systemctl isolate multi-user.target # Switch to CUI.

It's something like this. Please note that when you switch to CUI, the command line will not appear unless you press Ctrl + Alt + F2.

Ubuntu

In Ubuntu, it seems the only way is to change the default using systemctl set-default.
You can get the current default with systemctl get-default.
When changing it, please enter something like the multi-user.target mentioned above.

Conclusion

Have a great Linux life...