在虚拟机新安装了个CentOS7，图形界面启动太慢，想调整一下按照以前的经验改运行级别，输入：
vi /etc/inittab
然后发现跟之前不一样了，在inittab设置不再生效：
# 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
#
仔细读一下上面的提示
multi-user.target 类似与之前的runlevel 3
graphical.target 类似与之前的runlevel 5
按照上面的提示，查看当前的默认target输入命令：
[root@localhost ~]# systemctl get-default
graphical.target
[root@localhost ~]#
当前为graphical.target
修改为命令模式multi-user.target：
[root@localhost ~]# 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@localhost ~]#
查看一下当前，发现得到预期要求：
[root@localhost ~]# systemctl get-default
multi-user.target
[root@localhost ~]#
最后重启发现，果然是命令模式~~