问题 :yum不可用。

fujike029

[root@localhost ~]# yum install gcc

You have enabled checking of packages via GPG keys. This is a good thing.
However, you do not have any GPG public keys installed. You need to download
the keys for packages you wish to install and install them.
You can do that by running the command:
    rpm --import public.gpg.key
For more information contact your distribution or package provider.

后来更改了配置，将屏蔽的yum配置网址文件打开，
[root@localhost /]# cat /etc/yum.repos.d/fedora
fedora-devel.repo            fedora-updates.repo         
fedora.repo                  fedora-updates-testing.repo  
没有解决问题。
接着rpm –e yum，再安装新的不同版本的yum,
[root@localhost /]# rpm -q yum
yum-2.1.11-3
但问题依旧。