根据redhat操作系统版本及位数，下载对应centos的版本及位数的这些包：
yum-3.2.22-40.el5.centos.noarch.rpm
yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm
yum-metadata-parser-1.1.2-4.el5.x86_64.rpm
1.先安装yum-metadata-parser-1.1.2-4.el5.x86_64.rpm：
rpm -ivh yum-metadata-parser-1.1.2-4.el5.x86_64.rpm
2.同时安装yum-3.2.22-40.el5.centos.noarch.rpm、yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm
rpm -ivh yum-3.2.22-40.el5.centos.noarch.rpm yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm
3.获取163yum:
wget http://mirrors.163.com/.help/CentOS-Base-163.repo
文件内容替换：
把CentOS-Base-163.repo文件中的 “$releasever”，替换成“5”(5为系统的版本号。)
vi CentOS-Base-163.repo
:% s/\$releasever/5/g
[base]
name=CentOS-$releasever - Base
baseurl=http://mirrors.163.com/centos/6.3/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=http://mirrors.163.com/centos/6.3/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#packages used/produced in the build but not released
#[addons]
#name=CentOS-$releasever - Addons
#baseurl=http://mirrors.163.com/centos/$releasever/addons/$basearch/
#gpgcheck=1
#gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=http://mirrors.163.com/centos/6.3/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
baseurl=http://mirrors.163.com/centos/6.3/centosplus/$basearch/
gpgcheck=1
enabled=0
更新yum源/apt-get源：http://www.linuxdiyf.com/linux/13136.html
RedHat Enterprise Linux 5.4用CentOS 5.5 yum源替换：http://www.linuxdiyf.com/linux/8919.html
Fedora更新源（sohu yum源）：http://www.linuxdiyf.com/linux/11638.html
RHEL5.x&RHEL6.x更换CentOS yum源：http://www.linuxdiyf.com/linux/8248.html
RHEL5如何使用CentOS更新yum源：http://www.linuxdiyf.com/linux/5745.html