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

yum clean all

sudo yum makecache

vim编辑器:yum install vim
原文:https://www.cnblogs.com/smfx1314/p/10205782.html