[root@~ yum.repos.d]# yum list
Loaded plugins: fastestmirror, priorities, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Loading mirror speeds from cached hostfile
由于 redhat的yum在线更新是收费的，如果没有注册的话不能使用，如果要使用，需将redhat的yum卸载后，重启安装，再配置其他源。
#rpm -qa | grep subscription-manager 然后移除那出现的几项吧：
#yum remove subscription-manager-gnome
#yum remove subscription-manager-firstboot
#yum remove subscription-manager
然后可以去掉菜单里面的注册项
# yum remove rhn-setup-gnome
或者直接：
yum list subscription\*
yum remove subscription\* -y
