centos添加安装源

[kou@pyton yum.repos.d]$ cd /etc/yum.repos.d/
[kou@pyton yum.repos.d]$ ll
total 40
-rw-r--r-- 1 root root  563 Jul 20 17:48 akopytov_sysbench.repo
-rw-r--r-- 1 root root  675 Jun 15 10:46 CentOS-Base.repo
-rw-r--r-- 1 root root 1309 Nov 23  2018 CentOS-CR.repo
-rw-r--r-- 1 root root  649 Nov 23  2018 CentOS-Debuginfo.repo
-rw-r--r-- 1 root root  314 Nov 23  2018 CentOS-fasttrack.repo
-rw-r--r-- 1 root root  630 Nov 23  2018 CentOS-Media.repo
-rw-r--r-- 1 root root 1331 Nov 23  2018 CentOS-Sources.repo
-rw-r--r-- 1 root root 5701 Nov 23  2018 CentOS-Vault.repo
[kou@pyton yum.repos.d]$ yum install epel-release -y 在yum仓库添加一个repo结尾的文件