CentOS 7 yum命令无法使用解决方案

1、报错信息：

2、解决思路：

（1）进入/etc/yum.repos.d目录下找到  CentOS-Base.repo，依次执行命令：

cd /etc/yum.repos.d

cp  CentOS-Base.repo   CentOS-Base.repo.backup

vi CentOS-Base.repo

（2）进入后改为（全部复制替换原来的）：

# 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.

#