1、删除RHEL原有的yum
rpm -aq|grep yum|xargs rpm -e --nodeps
#删除
2、下载新的yum安装包
#这里我们使用CentOS的yum源（我的系统版本是rhel 6.5 as 64bit）
wget http://vault.centos.org/6.0/os/x86_64/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm
wget http://vault.centos.org/6.0/os/x86_64/Packages/yum-metadata-parser-1.1.2-14.1.el6.x86_64.rpm
wget http://vault.centos.org/6.0/os/x86_64/Packages/yum-3.2.27-14.el6.centos.noarch.rpm
wget http://vault.centos.org/6.0/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.26-11.el6.noarch.rpm
如果需要配置rhel 7版本系统的yum，下图进行说明：（其他版本应该也是通用的）
打开Packages后，在浏览器中 Ctrl + F 分别查找：
python-iniparse-0.3.1-2.1.el6.noarch.rpm
yum-metadata-parser-1.1.2-14.1.el6.x86_64.rpm
yum-3.2.27-14.el6.centos.noarch.rpm
yum-plugin-fastestmirror-1.1.26-11.el6.noarch.rpm
注意：按红色标注的查找即可，因为版本号也可能经常变动。
3、安装yum软件包
rpm -ivh python-iniparse-0.3.1-2.1.el6.noarch.rpm
rpm -ivh yum-metadata-parser-1.1.2-14.1.el6.i686.rpm
rpm -ivh yum-3.2.27-14.el6.centos.noarch.rpm
rpm -ivh yum-plugin-fastestmirror-1.1.26-11.el6.noarch.rpm
注意：最后两个安装包要放在一起同时安装，否则会提示相互依赖，安装失败。
4、更改yum源
#我们使用网易的CentOS镜像源
cd /etc/yum.repos.d/
wget http://mirrors.163.com/.help/CentOS6-Base-163.repo
vi CentOS6-Base-163.repo
#编辑文件
把文件里面的$releasever全部替换为版本号，即6 最后保存！（如果是其他版本，使用对应的版本号即可）
或者直接把下面的内存拷贝到CentOS6-Base-163.repo文件中即可（已经修改好，是按6修改的，如果需求其他版本，自行修改即可）
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.?You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-6 - Base - 163.com
baseurl=http://mirrors.163.com/centos/6/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-6 - Updates - 163.com
baseurl=http://mirrors.163.com/centos/6/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-6 - Extras - 163.com
baseurl=http://mirrors.163.com/centos/6/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6 - Plus - 163.com
baseurl=http://mirrors.163.com/centos/6/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-6 - Contrib - 163.com
baseurl=http://mirrors.163.com/centos/6/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=contrib
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-65
上面内容中的：gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6 也对应修改为自己的版本，如下图：
yum clean all
#清理yum缓存
yum makecache
#将服务器上的软件包信息缓存到本地,以提高搜索安装软件的速度
yum install vim*
#测试yum是否可用