Modify runlevel in Ubuntu

UbuntuDefault bootRunlevelYes 2. You can use runlevel to view the current default running level.
Debian (Ubuntu is based on Debian) Linux has always been started with runlevel 2 by default, and the runlevel definition is different from RedHat.
The runlevel of Debian is defined as follows:
0-Halt
1-single
2-full multi-user with Display Manager (GUI)
3-full multi-user with Display Manager (GUI)
4-full multi-user with Display Manager (GUI)
5-full multi-user with Display Manager (GUI)
6-Reboot
2 ~ There is no difference in level 5.
###### The RedHat runlevel is defined as follows:
###### 0-Halt
###### 1-single
###### 2-not used/user definable
###### 3-full multi-user no Display Manager
###### 4-not used/user definable
###### 5-full multi-user with Display Manager (GUI)
###### 6-Reboot

The corresponding configuration folder is as follows:
/Etc/rc0.d run level 0
/Etc/rc1.d run level 1
/Etc/rc2.d run level 2
/Etc/rc3.d run level 3
/Etc/rc4.d run level 4
/Etc/rc5.d run level 5
/Etc/rc6.d run level 6
The runlevel3-5 here is all into the graphical interface. This is inconsistent with other Linux releases. Generally, runlevel 3 is the multi user mode, that is, you can directly log on to the character interface, while runlevel 5 is the multi user mode with GUI, that is, you can log on to the graphic interface.
To change runlevel3 to multi user mode, perform the following steps:
1. Delete the startup items of the target group.
Find the guid Management System (guid) item in/etc/rc3.d and delete it. If you want to restore it, you can create a new link to the guid Management System (guid) in/etc/init. d.
2. Modify the default runlevel
For temporary modification, you can use telinit n, where N can be the runlevel code [0-6]. If you want to modify it for a long time, you can create an inittab file under/etc/(this file exists in other releases, but not in Debian and its derivative versions ). The file content is as follows:
ID: 3: initdefault:
Pay attention to the last colon, which indicates that the default value is runlevel 3 at startup.
Try sudo reboot to see if it is in the text interface.
References:
Http://www.linuxdiyf.com/viewarticle.php? Id = 92001
Http://www.debianadmin.com/debian-and-ubuntu-linux-run-levels.html