centos 7 添加 aliyun yum 源、epel源

原文：https://blog.csdn.net/ctypyb2002/article/details/80635924

备份原来的yum源
先备份，在任何环境下操作都是个良好习惯

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

设置aliyun的yum源

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

添加EPEL源
官员EPEL源，大家最好还是问下度娘。

wget -P /etc/yum.repos.d/ http://mirrors.aliyun.com/repo/epel-7.repo  

或者

wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
rpm -ivh ./epel-release-latest-7.noarch.rpm

清理缓存并生成新的缓存

yum clean all  
yum makecache