系统：CentOS 7.4
装了Python3觉得Python2没用了删了python2 导致yum不可用
1、 卸载现有python
rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps #卸载python
whereis python |xargs rm -frv ##删除所有残余文件
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
下载文件源 http://vault.centos.org/
首先在这里找到服务器对应的版本，如 7.4 进入这里目录 找到对应版本的rpm，替换下面的文件。
下载并安装，注意顺序，先安装python 然后 yum。不然安装后还会报错，重新来一遍。
# python安装
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
# yum安装
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
验证
#验证python
python
#验证yum
yum
来源：CSDN
作者：威震四海
链接：https://blog.csdn.net/Beyond_F4/article/details/103477176