1、删除现有Python和yum
要重装的话，就需要删干净python和yum，可以执行如下命令
# 删除python
rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps
whereis python |xargs rm -frv
whereis python
# 删除yum
rpm -qa|grep yum|xargs rpm -ev --allmatches --nodeps
whereis yum |xargs rm -frv
2、查看Linux系统版本
这一步是一定要执行的，因为后续需要下载相关依赖的，根据版本来下载
cat /etc/redhat-release
3、下载依赖
这里我选用的镜像站点为 阿里云开源镜像站 对应的地址为
mirrors.aliyun.com/centos/ 这里根据你的版本下载。
创建存放yum和python相关依赖包的目录
mkdir python_and_yum && cd $_
4、安装依赖
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/lvm2-python-libs-2.02.187-6.el7.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/libxml2-python-2.9.1-6.el7.5.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages//python-libs-2.7.5-89.el7.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-ipaddress-1.0.16-2.el7.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-backports-1.0-8.el7.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-backports-ssl_match_hostname-3.5.0.1-1.el7.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-2.7.5-89.el7.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-urlgrabber-3.10-10.el7.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-setuptools-0.9.8-7.el7.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-chardet-2.2.1-3.el7.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/rpm-python-4.11.3-45.el7.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-utils-1.1.31-54.el7_8.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-3.4.3-168.el7.centos.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-plugin-aliases-1.1.31-54.el7_8.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-plugin-protectbase-1.1.31-54.el7_8.noarch.rpm
wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-54.el7_8.noarch.rpm
如果不加 --nodeps --force 可能会提示依赖找不到，但实际上已经安装了。
5、大功告成
执行完毕后，再次在终端中就能查看对应版本信息。
yum --version
