Linux：redhat6.5使用yum时提示需要注册问题解决方案
一、问题
新安装了redhat6.5.安装后，登录系统，使用yum时候。提示：
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
无法使用。
redhat 默认自带的 yum 源需要注册，才能更新。我们想不花钱也可以更新，需要替换掉redhat的yum源。
二、检查是否安装yum包
rpm -qa |grep yum
三、删除redhat自带的yum包
卸载上面显示的所有yum包(不检查依赖，直接删除rpm包)：
rpm -qa|grep yum|xargs rpm -e --nodeps
再用命令查看是否已卸载
rpm -qa |grep yum
查看无信息显示表示已经卸载完成；
四、下载新的yum包(使用Centos6.5的yum包)
wget /centos/6/os/i386/Packages/yum-metadata-parser-1.1.2-16.el6.i686.rpm
wget /centos/6/os/i386/Packages/yum-3.2.29-40.el6.centos.noarch.rpm
wget /centos/6/os/i386/Packages/yum-plugin-fastestmirror-1.1.30-14.el6.noarch.rpm
五、安装yum软件包
注意:单个的安装包可能会依赖其它包(例如yum和yum-fastestmirror会相互依赖)，所以我们可以把所有这些包放在一起，用一行命令将它们同时安装即可：
rpm -ivh yum-metadata-parser-1.1.2-16.el6.i686.rpm yum-3.2.29-40.el6.centos.noarch.rpm yum-plugin-fastestmirror-1.1.30-14.el6.noarch.rpm
六、更换yum源(使用163的源)
cd /etc/yum.repos.d/wget /.help/CentOS6-Base-163.repo
vi CentOS6-Base-163.repo
编辑文件，把文件里面的$releasever全部替换为版本号，即更改为6，最后保存！或者直接把下面的内存拷贝到CentOS6-Base-163.repo文件中即可(已经修改好)
#CentOS-Base.repo#
#The mirror system uses the connecting IP address of the client and the#update status of each mirror to pick mirrors that are updated to and#geographically close to the client. You should use this for CentOS updates#unless you are manually picking other mirrors.#
#If the mirrorlist= does not work for you, as a fall back you can try the#remarked out baseurl= line instead.#
#[base]
name=CentOS-6 - Base -
baseurl=/centos/6/os/$basearch/
#mirrorlist=/?release=6.5&arch=$basearch&repo=os
gpgcheck=1gpgkey=/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-6 - Updates -
baseurl=/centos/6/updates/$basearch/
#mirrorlist=/?release=6.5&arch=$basearch&repo=updates
gpgcheck=1gpgkey=/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-6 - Extras -
baseurl=/centos/6/extras/$basearch/
#mirrorlist=/?release=6.5&arch=$basearch&repo=extras
gpgcheck=1gpgkey=/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6 - Plus -
baseurl=/centos/6/centosplus/$basearch/
#mirrorlist=/?release=6.5&arch=$basearch&repo=centosplus
gpgcheck=1enabled=0
gpgkey=/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-6 - Contrib -
baseurl=/centos/6/contrib/$basearch/
#mirrorlist=/?release=6.5&arch=$basearch&repo=contrib
gpgcheck=1enabled=0
gpgkey=/centos/RPM-GPG-KEY-CentOS-6
七、清除原有缓存
#重建缓存，以提高搜索安装软件的速度
yum clean all
八、更新系统
yum update
