由于，redhat企业版yum为收费项目，所以更换免费的源，这样在架设服务器的时候缺少某些组件可以用yum来进行添加，方便快捷，其实yum的速度没有太慢的，下面我将为大家介绍如何快速的修改yum源。
一、删除原yum所有组件
rpm -qa | grep yum | xargs rpm -e --nodeps #这条代码将删除redhat自带的yum
二、下载yum组件reh5-centos
rpm包已经有了，自己下载解压
[root@localhost yum]# ll total 1108 -rw-r--r-- 1 root root 34394 Feb 25 09:46 python-iniparse-0.2.3-4.el5.noarch.rpm -rw-r--r-- 1 root root 1026405 Feb 25 09:45 yum-3.2.22-26.el5.centos.noarch.rpm -rw-r--r-- 1 root root 19145 Feb 25 09:46 yum-fastestmirror-1.1.16-14.el5.centos.1.noarch.rpm -rw-r--r-- 1 root root 26053 Feb 25 09:41 yum-metadata-parser-1.1.2-3.el5.centos.i386.rpm
三、下面将要安装着四个软件包，切记按照我的安装顺序来，否则会出现报错，切记~
cd /tools/yum rpm -ivh python-iniparse-0.2.3-4.el5.noarch.rpm rpm -ivh yum-metadata-parser-1.1.2-3.el5.centos.i386.rpm rpm -ivh yum-3.2.22-26.el5.centos.noarch.rpm yum-fastestmirror-1.1.16-14.el5.centos.1.noarch.rpm
四、下面下载yum的配置文件，点击下载CentOS-Base163
上面的包是为redhat5.4准备的，如果你用不了的话，就把下面的代码写到CentOS-Base.repo中 保存在
/etc/yum.repos.d/
# CentOS-Base.repo
# # This file uses a new mirrorlist system developed by Lance Davis for CentOS.
# 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-$releasever – Base
baseurl=http://centos.ustc.edu.cn/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#released updates
[updates]
name=CentOS-$releasever – Updates
baseurl=http://centos.ustc.edu.cn/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever – Addons
baseurl=http://centos.ustc.edu.cn/centos/$releasever/addons/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#additional packages that may be useful
[extras]
name=CentOS-$releasever – Extras
baseurl=http://centos.ustc.edu.cn/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever – Plus
baseurl=http://centos.ustc.edu.cn/centos/$releasever/centosplus/$basearch/
gpgcheck=1 enabled=0
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
把这个文件放在 /etc/yum.repos.d/
yum clean all
yum makecache
yum update
大功告成，yum已经更新为不用花钱的啦
注：如何觉着下载这么多不方便，可以下下载yum这个包，放在/tools/下面 然后执行“sh /tools/yum/yum_stat.sh” 即可
