RHEL5.4设置Centos的yum源
由于redhat的yum在线更新是收费的，如果没有注册的话不能使用，如果要使用，需将redhat的yum卸载后，重启安装，再配置其他源，以下为详细过程：
1.删除redhat原有的yum
rpm -aq|grep yum|xargs rpm -e --nodeps
2.下载yum安装文件
wget http://mirrors.163.com/centos/5/os/i386/CentOS/yum-3.2.22-40.el5.centos.noarch.rpm
wget http://mirrors.163.com/centos/5/os/i386/CentOS/yum-metadata-parser-1.1.2-4.el5.i386.rpm
wget http://mirrors.163.com/centos/5/os/i386/CentOS/yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm
wget http://mirrors.163.com/centos/5/os/i386/CentOS/yum-updatesd-0.9-5.el5.noarch.rpm
3.进行安装yum
#rpm -ivh yum*.rpm
4.更新repo 文件
wget http://mirrors.163.com/.help/CentOS5-Base-163.repo -O CentOS-Base.repo
编辑CentOS-Base.repo把文件中$releasever替换为5。方法为： :s/$releasever/5/g
修改后如下：
[base]
name=CentOS-5 - Base - 163.com
baseurl=http://mirrors.163.com/centos/5/os/$basearch/
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
[updates]
name=CentOS-5 - Updates - 163.com
baseurl=http://mirrors.163.com/centos/5/updates/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
[addons]
name=CentOS-5 - Addons - 163.com
baseurl=http://mirrors.163.com/centos/5/addons/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
[extras]
name=CentOS-5 - Extras - 163.com
baseurl=http://mirrors.163.com/centos/5/extras/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
[centosplus]
name=CentOS-5 - Plus - 163.com
baseurl=http://mirrors.163.com/centos/5/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
[contrib]
name=CentOS-5 - Contrib - 163.com
baseurl=http://mirrors.163.com/centos/5/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
5.导入KEY文件，注意大小写
rpm --import http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
6.测试：
# yum clean all
# yum makecache
