Motivation

$ yum install lsof
-bash: yum: command not found

TL&DR;

Find rpm files from the following link:
http://mirror.centos.org/centos/6/os/x86_64/Packages/
wget the rpm file
Install via rpm -ivh *.rpm

# wget http://mirror.centos.org/centos/6/os/x86_64/Packages/yum-3.2.29-81.el6.centos.noarch.rpm
# rpm -ivh yum-3.2.29-81.el6.centos.noarch.rpm

Dependencies

# rpm -ivh yum-3.2.29-81.el6.centos.noarch.rpm
error: Failed dependencies:                                                                  
        python-iniparse is needed by yum-3.2.29-81.el6.centos.noarch                
        python-urlgrabber >= 3.9.1-10 is needed by yum-3.2.29-81.el6.centos.noarch
        yum-metadata-parser >= 1.1.0 is needed by yum-3.2.29-81.el6.centos.noarch                                                                                                                         
        yum-plugin-fastestmirror is needed by yum-3.2.29-81.el6.centos.noarch

Then find all the rpm file on the link above, and install all of them using wget and rpm.

If they have recursive dependencies, try installing at a time.

# rpm -ivh yum-*.rpm

Enable EPEL

Almost same as above...

# wget http://ftp-srv2.kddilabs.jp/Linux/distributions/fedora/epel/6/x86_64/epel-release-6-8.noarch.rpm
# rpm -ivh epel-release-6-8.noarch.rpm

Update repository before installing package

# yum check-update
# yum update