mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

[2] 進入yum源配置檔案所在資料夾

cd /etc/yum.repos.d/

[3] 下載163或者阿里雲的yum源配置檔案，放入/etc/yum.repos.d/(操作前請做好相應備份)

wget http://mirrors.163.com/.help/CentOS6-Base-163.repo

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo
 

centos6:

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo

centos7:

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

yum makecache

[5] 更新系統

yum -y update