-bash: /usr/bin/yum: 没有那个文件或目录 的解决方法

[root@Linux yum.repos.d]# yum
-bash: /usr/bin/yum: 没有那个文件或目录

[root@Linux yum.repos.d]# rpm -ivh --nodeps http://mirrors.163.com/centos/5/os/x86_64/CentOS//yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm 
Retrieving http://mirrors.163.com/centos/5/os/x86_64/CentOS//yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm
Preparing...                ########################################### [100%]

   1:yum-fastestmirror      ########################################### [100%]

[root@Linux yum.repos.d]# rpm -ivh --nodeps http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm 
Retrieving http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm
Preparing...                ########################################### [100%]

package yum-fastestmirror-1.1.16-21.el5.centos.noarch is already installed

[root@Linux yum.repos.d]# rpm -ivh --nodeps http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-metadata-parser-1.1.2-4.el5.x86_64.rpm   
Retrieving http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-metadata-parser-1.1.2-4.el5.x86_64.rpm
Preparing...                ########################################### [100%]

   1:yum-metadata-parser    ########################################### [100%]

[root@Linux yum.repos.d]# rpm -ivh --nodeps http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-3.2.22-40.el5.centos.noarch.rpm 
Retrieving http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-3.2.22-40.el5.centos.noarch.rpm
Preparing...                ########################################### [100%]

   1:yum                    ########################################### [100%]

[root@Linux yum.repos.d]# yum

已解决。