Linux yum换源

执行下列代码
rpm -qa |grep yum
rpm -qa|grep yum|xargs rpm -e --nodeps

rpm -qa |grep yum
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-45.el7.x86_64.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/yum-3.4.3-168.el7.centos.noarch.rpm
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-plugin-fastestmirror-1.1.31-54.el7_8.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-utils-1.1.31-54.el7_8.noarch.rpm
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-*
cd /etc/yum.repos.d/
sed -i 's#$releasever#7#g' CentOS7-Base.repo
yum clean all
yum makecache
yum install vim

其中，sed -i 's#$releasever#7#g' CentOS7-Base.repo
相当于wget http://mirrors.163.com/.help/CentOS7-Base-163.repo
rm-rf Centos-Base.repo
mv CentOS7-Base-163.repo CentOS7-Base.repo //左边覆盖右边，重命名