This system is not registered to Red Hat Subscription Management. You can use subscription-manager..

This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register

我的Linux系统是RedHat Enterprise Linux 6.6-x86_64，在使用yum命令出现This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.原因就是因为redhat的yum源是需要注册付费的。

解决办法：

1.检查yum包 rpm -qa |grep yum 
2.删除自带包 rpm -qa|grep yum|xargs rpm -e --nodeps
3.再检查一下 rpm -qa |grep yum

没有yum包则删除干净

4.下载更新包

wget http://mirrors.163.com/centos/6/os/x86_64/Packages/python-urlgrabber-3.9.1-11.el6.noarch.rpm 
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-41.el6.noarch.rpm 
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-3.2.29-81.el6.centos.noarch.rpm 
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-updateonboot-1.1.30-41.el6.noarch.rpm 
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-metadata-parser-1.1.2-16.el6.x86_64.rpm 
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-utils-1.1.30-41.el6.noarch.rpm

如果出现404的情况可以访问：http://mirrors.163.com/centos/6/os/x86_64/Packages/ 自己找下，然后改成对应的包名就可以了，有可能centos更新包名版本号变了。

5.执行安装 
rpm -ivh yum-* 

出现python-urlgrabber >= 3.9.1-10 is needed by yum-3.2.29-81.el6.centos.noarch 这个中情况更新rpm -Uvh python-urlgrabber版本执行：

rpm -Uvh python-urlgrabber-3.9.1-11.el6.noarch.rpm

在执行： 
rpm -ivh yum-*

6.切换源 
cd /etc/yum.repos.d/ 
mv redhat.repo redhat.repo.bak 
mv rhel-source.repo rhel-source.repo.bak 
vi /etc/yum.repos.d/CentOS-Base.repo

粘贴如下信息

#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
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=os
baseurl=http://mirrors.163.com/centos/7/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6.5
#released updates
[updates]
name=CentOS-6 - Updates - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=updates
baseurl=http://mirrors.163.com/centos/7/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6.5
#additional packages that may be useful
[extras]
name=CentOS-6 - Extras - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=6&arch=$basearch&repo=extras
baseurl=http://mirrors.163.com/centos/7/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6.5
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6 - Plus - 163.com
baseurl=http://mirrors.163.com/centos/7/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6.5

7.清理缓存 
yum clean all

yum makecache

如果出现以下问题：

原因是文件内容格式不对，检查每行是否有空格，删掉空格

9.安装完成