yum安装图形界面：
1) yum groupinstall "X Window System"
2) 安装GNOME桌面环境 yum groupinstall "GNOME Desktop Environment"
安装KDE 桌面环境 yum groupinstall "KDE (K Desktop Environment)"
3) 图形界面想要卸载：
yum groupremove "GNOME Desktop Environment"
yum groupremove "X Window System"
