显示系统已经安装的组件，和可以安装的组件:
#yum grouplist
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)"
卸载GNOME桌面环境
yum groupremove "GNOME Desktop Environment"
卸载KDE桌面环境
yum groupremove "KDE (K Desktop Environment)"