卸载现有的Python和Yum
1、删除现有Python##强制删除已安装程序及其关联rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps ##删除所有残余文件 ##xargs，允许你对输出执行其他某些命令whereis python |xargs rm -frv ##验证删除，返回无结果whereis python 2、删除现有的yum、强制删除已安装程序及其关联##强制删除已安装程序及其关联rpm -qa|grep yum|xargs rpm -ev --allmatches --nodeps##强制删除所有残余文件whereis yum |xargs rm -frv下载所需的rpm包
##查看自己系统版本的命令cat /etc/redhat-release #CentOS Linux release 7.8.2003 (Core)##下载相应的包地址：http://mirrors.ustc.edu.cn/centos/7.8.2003(自己系统版本号)/os/x86_64/Packages/##所需要的包##pythonpython-2.7.5-88.el7.x86_64.rpmpython-iniparse-0.4-9.el7.noarch.rpmpython-pycurl-7.19.0-19.el7.x86_64.rpmpython-devel-2.7.5-88.el7.x86_64.rpmpython-libs-2.7.5-88.el7.x86_64.rpmpython-urlgrabber-3.10-10.el7.noarch.rpmrpm-python-4.11.3-43.el7.x86_64.rpm##yumyum-3.4.3-167.el7.centos.noarch.rpmyum-metadata-parser-1.1.4-10.el7.x86_64.rpmyum-plugin-fastestmirror-1.1.31-53.el7.noarch.rpm##创建目录python和yum用以存放rpm包mkdir /usr/local/rpm ##使用wget分别下载python以及yum的rpm包（注意：一定要和系统的版本号对应）地址如下python
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/python-2.7.5-88.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/python-devel-2.7.5-88.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/python-libs-2.7.5-88.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/python-urlgrabber-3.10-10.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/rpm-python-4.11.3-43.el7.x86_64.rpm
yum
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/yum-3.4.3-167.el7.centos.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7.8.2003/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-53.el7.noarch.rpm
安装python以及yum的rpm包
##安装pythoncd /usr/local/rpmrpm -ivh python-* rpm-python-*##出现安装包的依赖问题，此时如下解决即可：--nodeps --force为不考虑依赖包，强制安装。rpm -ivh python-* rpm-python-* --nodeps --force##安装完后即可运行python:## pythonPython 2.7.5 (default,Nov 20 2020,21:18:26)##安装yumrpm -ivh yum-*##至此yum重新安装成功！##生成缓存yum clean all yum makecache yum updateyum工具及使用命令
## 使用一个小工具yum-complete-transactionyum install yum-utils## 清理未完成的yum事务yum-complete-transaction --cleanup-only## 列出有问题的软件包package-cleanup --problems## 列出重复安装的软件包package-cleanup --dupes## 清除重复的已安装的包package-cleanup --cleandupes
