RHEL改用Centos源

实验室购买的rhel订阅到期了。无法使用yum来解决依赖包问题，是个很头痛的事。

逼不得已将rhel的源改为centos。

1. 系统环境：RHEL 5
2. 备份源文件#cp -a /etc/yum.repos.d/rhel-debuginfo.repo{,.bak}
3. 创建CentOS-Base.repo 为如下内容：

   [base]
   name=CentOS-5 - Base
   repo=os
   baseurl=http://centos.ustc.edu.cn/centos/5/os/$basearch/
   gpgcheck=1
   gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5[update]
   name=CentOS-5 - Updates
   baseurl=http://centos.ustc.edu.cn/centos/5/updates/$basearch/
   gpgcheck=1
   gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5[addons]
   name=CentOS-5 - Addons
   baseurl=http://centos.ustc.edu.cn/centos/5/addons/$basearch/
   gpgcheck=1
   gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
   
   [extras]
   name=CentOS-5 - Extras
   baseurl=http://centos.ustc.edu.cn/centos/5/extras/$basearch/
   gpgcheck=1
   gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
   
   [centosplus]
   name=CentOS-5 - Plus
   baseurl=http://centos.ustc.edu.cn/centos/5/centosplus/$basearch/
   gpgcheck=1
   enabled=0
   gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
   
   [contrib]
   name=CentOS-5 - Contrib
   baseurl=http://centos.ustc.edu.cn/centos/5/contrib/$basearch/
   gpgcheck=1
   enabled=0
   gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5

4. 导入KEY文件
   #rpm –import http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
5. 测试一下，看看是否正常 #yum list