装python3.10时删了python3.7，结果导致yum也完蛋了。恢复的思路：彻底删除python和yum后重装。
一、删除：
1、卸载现有python
rpm -qa | grep python | xargs rpm -ev --allmatches --nodeps ##卸载python whereis python | xargs rm -frv ##删除所有参与文件 whereis python ##验证删除，返回无结果
2、删除现有的yum
rpm -qa | grep yum | xargs rpm -ev --allmatches --nodeps #删除yum whereis yum | xargs rm -frv #删除残留文件 whereis yum #验证删除完成
二、安装（相关的下载文件源根据自己的操作系统进行替换）：
1、按以下顺序安装python
rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/python-2.7.5-58.el7.x86_64.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/python-devel-2.7.5-58.el7.x86_64.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/python-libs-2.7.5-58.el7.x86_64.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/rpm-python-4.11.3-25.el7.x86_64.rpm
2、按以下顺序安装yum
rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/yum-3.4.3-154.el7.centos.noarch.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm rpm -ivh --nodeps http://vault.centos.org/7.4.1708/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-42.el7.noarch.rpm
三、验证