CentOS7.2.1511卸载并重新安装python2.7及yum

本来想在服务器CentOS7上升级python2.7至python3.5结果误删了yum，导致yum死活用不了。尝试一波方案，结果都没有解决，只能卸载并重新安装python和yum。

1.卸载python:

#rpm -qa|grep python|xargs rpm -e --allmatches --nodeps

#whereis python|xargs rm -fr

2.卸载yum:

#rpm -qa|grep yum|xargs rpm -e --allmatches --nodeps

#rm -rf /etc/yum.repos.d/*

#whereis yum|xargs rm -fr

3.创建目录python和yum用以存放rpm包：

#mkdir /usr/local/src/python

#mkdir /usr/local/src/yum

4.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）

    （1）下载python的rpm包：

#cd /usr/local/src/python        进入目录

#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-2.7.5-34.el7.x86_64.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-pycurl-7.19.0-17.el7.x86_64.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-devel-2.7.5-34.el7.x86_64.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-libs-2.7.5-34.el7.x86_64.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-urlgrabber-3.10-7.el7.noarch.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/rpm-python-4.11.3-17.el7.x86_64.rpm

    （2）下载yum的rpm包：

#cd /usr/local/src/yum        

#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-3.4.3-132.el7.centos.0.1.noarch.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
#wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-34.el7.noarch.rpm

5.安装python以及yum的rpm包

    （1）安装python:

#cd /usr/local/src/python 

#rpm -ivh python-*   rpm-python-* 

           出现安装包的依赖问题，此时如下解决即可：

#rpm -ivh python-*   rpm-python-* --nodeps --force

            --nodeps --force为不考虑依赖包，强制安装。

            安装完后即可运行python:

    （2）安装yum:

#cd /usr/local/src/yum 

#rpm -ivh yum-* 

        至此yum重新安装成功！