問題描述
最近想要將服務器上的Python2.7升級成3.x的版本時。使用了如下命令：
（1）強制刪除已安裝python及其關聯 # rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps （2）刪除殘余文件 # whereis python|xargs rm -frv
執行命令后導致服務器上的yum命令和python命令都無法使用。出現以下報錯：
[root@test ~]# python -V -bash: /usr/bin/python: No such file or directory [root@test ~]# yum -bash: /usr/bin/yum: No such file or directory
解決方案
1.創建目錄用來存放rpm包：
mkdir /usr/local/src/python
查看系統版本：
lsb_release -a
查看位數
getconf LONG_BIT
2.進入目錄，使用wget分別下載python以及yum的rpm包
http://vault.centos.org/ 這個地址可以下載不同版本系統對應的包（注意：一定要和系統的版本號對應）
可以看到我們的系統版本是7.5.1804，這里下載以下文件
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/lvm2-python-libs-2.02.177-4.el7.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/libxml2-python-2.9.1-6.el7_2.3.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-libs-2.7.5-68.el7.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-ipaddress-1.0.16-2.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-backports-1.0-8.el7.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-backports-ssl_match_hostname-3.5.0.1-1.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-2.7.5-68.el7.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-setuptools-0.9.8-7.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-chardet-2.2.1-1.el7_1.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/rpm-python-4.11.3-32.el7.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-utils-1.1.31-45.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-3.4.3-158.el7.centos.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-plugin-aliases-1.1.31-45.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-plugin-protectbase-1.1.31-45.el7.noarch.rpm wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm
3.執行以下命令，開始安裝
rpm -Uvh --replacepkgs lvm2-python-libs*.rpm --nodeps --force rpm -Uvh --replacepkgs libxml2-python*.rpm --nodeps --force rpm -Uvh --replacepkgs python*.rpm --nodeps --force rpm -Uvh --replacepkgs rpm-python*.rpm yum*.rpm --nodeps --force
說明：--nodeps --force表示僅安裝當前的，不考慮安裝所需的依賴
4.測試python是否可用
python命令正常
5.測試yum是否可用
yum命令正常
至此centos7.5重新安裝python2.7及yum完成。