linux添加镜像163和阿里云

yum配置文件所在路径：

/etc/yum.repos.d/

163镜像：

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

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

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

阿里云镜像：

CentOS7
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

CentOS6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo

CentOS5
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo

下载镜像后，yum makecache，就可以使用镜像更新系统。