爱华网rpm -aq|grep yum|xargs rpm -e --nodeps
Step2：下载新的yum（）源进行安装，注意操作系统支持64位还是32位
wgethttp://mirror.centos.org/centos/6.2/os/x86_64/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm
wgethttp://mirror.centos.org/centos/6.2/os/x86_64/Packages/yum-3.2.29-22.el6.centos.noarch.rpm
wgethttp://mirror.centos.org/centos/6.2/os/x86_64/Packages/yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
wgethttp://mirror.centos.org/centos/6.2/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-10.el6.noarch.rpm
rpm -ivh python-iniparse-0.3.1-2.1.el6.noarch.rpm
rpm -ivh yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
rpm -ivh yum-3.2.29-22.el6.centos.noarch.rpmyum-plugin-fastestmirror-1.1.30-10.el6.noarch.rpm（有依赖关系，一起安装）
Step3：更改yum源
cd /etc/yum.repos.d/
wget http://mirrors.163.com/.help/CentOS6-Base-163.repo
--将文件中的$releasever全部版本号，我用的RHEL6.2，故改为6.2即可。使用命令【：%s/$releasever/6.2/g】
vim CentOS6-Base-163.repo
Step4: 清理缓存并新建缓存
yum clean all
yum makecache
