转载自:http://www.cnblogs.com/smartvessel/archive/2012/09/05/2671796.html
cd /etc/yum.repos.d/ mv CentOS-Base.repo CentOS-Base.repo.backwget http://mirrors.163.com/.help/CentOS6-Base-163.repomv CentOS6-Base-163.repo CentOS-Base.repoyum makecache