Disable graphic interface knowledge in Ubuntu 12.04

Background
1. Ubuntu running level
The Linux system runs on a specified running level at any time, and different running-level programs and services are different. The work to be done and the purpose to be achieved are different, the system can switch between these running levels to complete different tasks.
Ubuntu system running level:
* 0: shutdown level
* 1: run scripts in the rc. sysinit and rc1.d directories at the single user level.
* 2: multiple users, but the system does not start NFS or character mode. In some linux systems, level 2 is the default mode and has network functions, such as ubuntu. debian.
* 3: multi-user, character mode, system startup with network functions, RedHat common operation level
* 4: User-Defined Level
* 5: graphic interface mode, common redhat running level
* 6: restart level
* S: run only the rc. sysinit file.
2. view the current running level and run the following command:
Runlevel
(Runlevel indicates the last running level and the current running level. "N" indicates that the previous running level does not exist .)
3. Switch the running level and run the following command:
Int [0123456Ss]
(That is, the init command is followed by a parameter. this parameter is the code of the running level to be switched to, for example, shutdown with the init 0 command and restart with the init 6 command .)

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Console switch under Gui
Crtl + alt + F1 ~ F7

F1 ~ F6 is the console with 6 characters. F7 returns to the graphic interface console.

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Ubuntu12.04 starts and directly enters the character interface:

Modify the GRUB configuration file (it is best not to change grub. conf directly)

/Etc/default/grub

Set GRUB_CMDLINE_LINUX_DEFAULT = "quiet splash"

Replace with GRUB_CMDLINE_LINUX_DEFAULT = "text"

After saving, sudo update-grub, grub. conf will be updated.

Restart

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In Ubuntu12.04, the character interface starts the graphical interface:

Startx