CentOS 7.6 替换阿里云 YUM 源完整命令

1.备份原有官方源

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

2.下载阿里云 CentOS7 源文件

curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo3

无 curl 用 wget：

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

3.可选：阿里云 epel 扩展源（常用软件）

curl -o /etc/yum.repos.d/epel.repo https://mirrors.aliyun.com/repo/epel-7.repo

4.清理旧缓存并生成新缓存

yum clean all
yum makecache

5.验证

yum list