centos 7.4 "X Window System" 安装
参考文档:http://blog.51cto.com/laobaiv1/2127873
yum groupinstall "X Window System" #先安装Xwindows(安装X)
startx #启动xwindow 进入图形化桌面(进入图形界面)
systemctl get-default #查看默认运行级别
cat /etc/inittab |grep runlevel #查看 /etc/inittab 文件
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
# multi-user.target: analogous to runlevel 3 #运行级别 3,多用户命令行模式
# graphical.target: analogous to runlevel 5 #运行级别 5,多用户图形化界面
systemctl set-default graphical.target \\设置默认图形化运行级别
yum grouplist #然后安装我们需要的图形界面软件,GNOME(GNOME Desktop)
yum groupinstall "GNOME Desktop" #(此步可选)然后安装我们需要的图形界面软件,GNOME(GNOME Desktop)