修改yum源:
1)mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
访问:https://mirrors.ustc.edu.cn/help/centos.html
把对应版本的内容粘贴进去。
2)vi /etc/yum.repos.d/CentOS-Base.repo
3)sudo yum makecache(用时较长)
4. yum install wget
5. yum install vim
6. yum install openssh-clients
参考博客