在大多数的linux发行版本中，通常有8个 runlevel
Runlevel System State
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
S, s Single user mode
可以在文件 /etc/inittab 中查看
[root@wode003 ~]# cat/etc/inittab
-bash: cat/etc/inittab: 没有那个文件或目录
[root@wode003 ~]# cat /etc/inittab
# inittab is no longer used when using systemd.
#
# ADDING ConFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target
#
// get-default
[root@wode003 ~]# systemctl get-default
graphical.target
// set-default
[root@wode003 ~]# systemctl set-default multi-user.target
rm '/etc/systemd/system/default.target'
ln -s '/usr/lib/systemd/system/multi-user.target' '/etc/systemd/system/default.target'
[root@wode003 ~]# systemctl get-default
multi-user.target
[root@wode003 ~]#
