# cat /etc/redhat-releasevim
# cd /etc/yum.repos.dcentos
# vim CentOS-AppStream.repoide
baseurl=https://mirrors.aliyun.com/centos/$releasever/AppStream/$basearch/os/url
# vim CentOS-Base.repospa
baseurl=https://mirrors.aliyun.com/centos/$releasever/BaseOS/$basearch/os/blog
# vim CentOS-Extras.repoit
baseurl=https://mirrors.aliyun.com/centos/$releasever/extras/$basearch/os/class
# dnf -y install epel-releaseim
# dnf clean allyum
# dnf makecache
# dnf repolist