由于正常 CentOS 源不在教育网免费 IP 列表里，或者使用 VPN，或者更换自己的源，下面提供 哈尔滨工业大学 自己的源，我这里用的是 EL6.3
Step1
1 $ touch CentOS-Base.repo
编辑 CentOS-Base 添加:
# CentOS-Base.repo # The mirror system uses the connecting IP address of the client and the # update status of each mirror to pick mirrors that are updated to and # geographically close to the client. You should use this for CentOS updates # unless you are manually picking other mirrors. # # If the mirrorlist= does not work for you, as a fall back you can try the # remarked out baseurl= line instead. # # [base] name=CentOS-$releasever - Base baseurl=http://run.hit.edu.cn/centos/6.3/os/$basearch/ gpgcheck=1 gpgkey=http://run.hit.edu.cn/centos/RPM-GPG-KEY-CentOS-6 #released updates [updates] name=CentOS-$releasever - Updates baseurl=http://run.hit.edu.cn/centos/6.3/updates/$basearch/ gpgcheck=1 gpgkey=http://run.hit.edu.cn/centos/RPM-GPG-KEY-CentOS-6 #additional packages that may be useful [extras] name=CentOS-$releasever - Extras baseurl=http://run.hit.edu.cn/centos/6.3/extras/$basearch/ gpgcheck=1 gpgkey=http://run.hit.edu.cn/centos/RPM-GPG-KEY-CentOS-6 #additional packages that extend functionality of existing packages [centosplus] name=CentOS-$releasever - Plus baseurl=http://run.hit.edu.cn/centos/6.3/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=http://run.hit.edu.cn/centos/RPM-GPG-KEY-CentOS-6
Step2
替换系统的默认 repo:
1 $ sudo mv CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo
Step3
1 # 清除暂存中旧的 rpm 头文件和包文件
2 $ sudo yum clean all
3 # 把服务器的包信息下载到本地电脑缓存起来
4 $ sudo yum makecache
5 # 更新所有的 rpm 包
6 $ sudo yum update
下面就可以正常安装软件了，我要 screen，expect
