centos7安装gcc,yum报错Repository base is listed more than once in the configuration

yum 安装gcc时报错：

Loaded plugins: fastestmirror

Repository base is listed more than once in the configuration

查了各种资料，没解决，最后发现了错误原因（只是其中一种原因）；

 蓝色框：这些错误尝试各种解决仍无效。

红色框：最后发现是yum 被占用了。论看全部信息的重要性

绿色框：果然yum被占用 kill 掉

配置阿里源 

 wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

安装gcc

yum -y install gcc gcc-c++ kernel-devel

查看gcc

gcc -v

离线安装未尝试

镜像库下载下列包 http://mirrors.aliyun.com/centos/7/os/x86_64/Packages/

mpfr-3.1.1-4.el7.x86_64.rpm
libmpc-1.0.1-3.el7.x86_64.rpm
kernel-headers-3.10.0-123.el7.x86_64.rpm
glibc-headers-2.17-55.el7.x86_64.rpm
glibc-devel-2.17-55.el7.x86_64.rpm
cpp-4.8.2-16.el7.x86_64.rpm
gcc-4.8.2-16.el7.x86_64.rpm　　　　

安装

rpm -Uvh *.rpm --nodeps --force