Understanding of the running level of ubuntu and ubuntu linux systems (Closing the graphic interface)

Ubuntu and ubuntu-like linux systems (close the graphic interface) for linux, the old bird uses debian, but more people use ubutnu or derivative version of ubuntu, for example, linuxmint and linuxdeepin made in China are mostly about how to configure the video card driver and 3D effect, and there are very few times when the graphic interface is closed. Unless you break the system file, you cannot enter the graphic interface .. First, understand the ubuntu running level: Generally, the running level of linux is 6 (4 is not defined, but it should be acceptable): 0--6, 0 Halt the system 1 Single user mode 2 Basic multi user mode 3 Multi user mode 5 Multi user mode with GUI 6 Reboot the system is above the general linux operating level, started by init, init is a user-level process started by the Linux kernel. For details, see network. However, ubuntu and its derivative versions are different. 1. Use upstart instead of init to start the system process. 2. Change the running level. 3. For others, ubutnu has eight running levels: 0-6 S 0: shutdown 1: Single User mod 2--5: multi-user mode, there is basically no difference (this is different from general linux, 2 is the default level) 6: restart S: single-user recovery mode, run few processes, and view the service running level: $ runlevel change run level: telinit * (0-6 S) (generally there is no need to change to S) at/etc/rc $. the d directory defines various running services. To disable the X service and the x client in ubuntu, you can simply terminate these services by using the desktop initiator and other processes. However, we need to define the terminal mode as soon as the desktop is started. (Ubuntu server version is default to enter the terminal, it is should have not configured graphics X Service) Because 2-5 are roughly the same, in the/etc/rc1-5.d directory can not find the desktop starter service, in earlier versions, I may have ubuntu11.10, and then in/etc/init/Lighttpd. conf finds the configuration of the starter. By default, X is started from 2 to 5. You can modify the configuration so that a running level does not start the desktop. (This is the configuration of linuxmint.) the configuration of ubuntu should be for the configuration of gmt1. The following text indicates that although ubutnu uses upstart, it also follows the intitab modification/etc/inittab (if not, create a new root user) id: 3: initdefault: script # Check for default runlevel in/etc/inittab if [-r/etc/inittab] then eval "$ (sed-nre's/^ [^ #] [^:] * :( [0-6sS]): initdefault :. */DEFAULT_RUNLEVEL = "\ 1";/P'/etc/inittab | true) "fi # Check kernel command-line for typical arguments for ARG in $ (cat/proc/cmdline) do case" $ {ARG} "in-B | emergency) # Em Ergency shell [-n "$ {FROM_SINGLE_USER_MODE}"] | sulogin; [0123456sS]) Restart to enter the terminal.