redhat7 重新配置yum源

在RedHat下使用yum安装软件时出现This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
就是要注册交费才能使用yum，只好自己重新配置yum源，在此记录下这次配置过程

第一步：删除旧yum包

rpm -qa |grep yum

rpm -qa|grep yum|xargs rpm -e --nodeps

第二步：查看redhat的版本和位数

uname -a

cat /etc/redhat-release 

第三步：下载最新rpm包

wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm

wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-168.el7.centos.noarch.rpm

wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-54.el7_8.noarch.rpm

wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-urlgrabber-3.10-10.el7.noarch.rpm

wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-45.el7.x86_64.rpm

第四步：安装

rpm -Uvh rpm-4.11.3-45.el7.x86_64.rpm --nodeps

rpm -Uvh python-urlgrabber-3.10-10.el7.noarch.rpm --nodeps

rpm -ivh yum-3.4.3-168.el7.centos.noarch.rpm yum-metadata-parser-1.1.4-10.el7.x86_64.rpm yum-plugin-fastestmirror-1.1.31-54.el7_8.noarch.rpm

第五步：修改yum源配置文件

cd /etc/yum.repos.d

mv redhat.repo redhat.repo.bak

wget http://mirrors.163.com/.help/CentOS7-Base-163.repo

vim CentOS6-Base-163.repo 使用全文替换： :1,$s/$releasever/7

第六步：验证

重建缓存yum makecache

yum repolist

yum install gcc gcc-c++ -y