rpm -qa | grep yum | xargs rpm -e --nodeps
http://mirrors.163.com/centos/7/os/x86_64/Packages/
[root@xilong ~]# mkdir -p /server/packages [root@xilong ~]# cd /server/packages/ wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-3.4.3-158.el7.centos.noarch.rpm wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm [root@xilong packages]# ls -l total 1368 -rw-r--r--. 1 root root 39800 Jul 4 2014 python-iniparse-0.4-9.el7.noarch.rpm -rw-r--r--. 1 root root 1292216 Apr 25 19:52 yum-3.4.3-158.el7.centos.noarch.rpm -rw-r--r--. 1 root root 28348 Jul 4 2014 yum-metadata-parser-1.1.4-10.el7.x86_64.rpm -rw-r--r--. 1 root root 33660 Apr 25 19:52 yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm [root@xilong packages]# rpm -ivh yum* [root@xilong packages]# rpm -ivh python-iniparse-0.4-9.el7.noarch.rpm
下载yum的配置文件
[root@xilong ~]# cd /etc/yum.repos.d/ [root@xilong yum.repos.d]# ls redhat.repo [root@xilong yum.repos.d]# wget http://mirrors.163.com/.help/CentOS7-Base-163.repo [root@xilong yum.repos.d]# sed ‘s#$releasever#7#g‘ CentOS7-Base-163.repo [root@xilong yum.repos.d]# sed ‘s#$releasever#7#g‘ CentOS7-Base-163.repo -i ##[root@xilong yum.repos.d]# sed ‘s#163#aliyun#g‘ CentOS7-Base-163.repo -i
将原有的yum文件删除或重命名
[root@8129cfba77d8 yum.repos.d]# rm -rf redhat.repo [root@8129cfba77d8 yum.repos.d]# mv yum.repo yum.repo.bak [root@8129cfba77d8 yum.repos.d]# mv Centos-7.repo yum.repo [root@8129cfba77d8 yum.repos.d]# vi yum.repo
:%s/$releasever/7/g
最后清除缓存
yum clean all && yum makecache
原文：https://www.cnblogs.com/Stay-J/p/11383095.html