安装epel

(可选步骤，可以跳过)

　　sudo yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

安装gnome tweak

　　sudo yum install gnome-tweak-tool

安装dash to dock

　　sudo yum install gnome-shell-extension-dash-to-dock