1.源所在的目录:

/etc/yum.repos.d/

在更换之前可以先备份自己的源,防止出错,

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

2.抓取
Centos 5.X

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

wget http://mirrors.163.com/.help/CentOS5-Base-163.repo //网易

Centos 6.X

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

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

Centos 7.X

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

wget http://mirrors.163.com/.help/CentOS7-Base-163.repo //网易

3.下载成功后

yum clean all

yum makecache

完成！