linux yum:command not found

一.http://mirrors.163.com/centos/7/os/x86_64/Packages/ 下载
1.python-iniparse-0.4-9.el7.noarch.rpm
2.yum-3.4.3-163.el7.centos.noarch.rpm
3.yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
4.yum-plugin-fastestmirror-1.1.31-52.el7.noarch.rpm
二。上传到linux xxxxx文件下，进入xxxxx文件夹下进行安装
rpm -ivh --force --nodeps python-iniparse-0.4-9.el7.noarch.rpm
rpm -ivh --force --nodeps yum-3.4.3-163.el7.centos.noarch.rpm
rpm -ivh --force --nodeps yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
rpm -ivh --force --nodeps yum-plugin-fastestmirror-1.1.31-52.el7.noarch.rpm
三。下载yum-3.4.3.tar.gz
http://yum.baseurl.org/download/3.4/yum-3.4.3.tar.gz
上传到linux xxxxx文件下，进行解压，解压后进入解压后的目录下
执行./yummain.py update