sudo cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
查版本号
lsb_release -a
sudo wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.tencent.com/repo/centos6_base.repo
sudo yum clean all
sudo yum makecache
yum repolist all