请参考这篇博客：centos7.6.1810重装python和yum
查看版本号
cat /etc/redhat-release
安装过程
卸载所有python环境和yum
1、删除现有Python
[root@test ~]# rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps ##强制删除已安装程序及其关联
[root@test ~]# whereis python |xargs rm -frv ##删除所有残余文件 ##xargs，允许你对输出执行其他某些命令
[root@test ~]# whereis python ##验证删除，返回无结果
2、删除现有的yum
[root@test ~]# rpm -qa|grep yum|xargs rpm -ev --allmatches --nodeps
[root@test ~]# whereis yum |xargs rm -frv
从http://vault.centos.org/7.6.1810/os/x86_64/Packages/下载所有需要的安装包，注意按顺序下载:
创建目录python和yum用以存放rpm包
mkdir /usr/local/src/python
mkdir /usr/local/src/yum
cd /usr/local/src/python
下载所有的python包，这里安装完是2.7版本的，因为yum不支持python3.7
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-2.7.5-76.el7.x86_64.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-backports-1.0-8.el7.x86_64.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-backports-ssl_match_hostname-3.5.0.1-1.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-chardet-2.2.1-1.el7_1.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-ipaddress-1.0.16-2.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-libs-2.7.5-76.el7.x86_64.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-setuptools-0.9.8-7.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/python-urlgrabber-3.10-9.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/rpm-python-4.11.3-35.el7.x86_64.rpm
cd /usr/local/src/yum
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/yum-3.4.3-161.el7.centos.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/yum-plugin-aliases-1.1.31-50.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-50.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/yum-plugin-protectbase-1.1.31-50.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/yum-utils-1.1.31-50.el7.noarch.rpm
wget http://vault.centos.org/7.6.1810/os/x86_64/Packages/libxml2-python-2.9.1-6.el7_2.3.x86_64.rpm
cd /usr/local/src/python
rpm -ivh python-* rpm-python-*
安装完之后运行一下python查看是否工作正常
cd /usr/local/src/yum
rpm -ivh yum-* libxml*
同样执行完毕之后运行yum命令
