u r 80% wrong

and maybe 100%

use commend below
cd /tmp
wget http://www.rarlabs.com/rar/rarlinux-3.8.0.tar.gz


tar -zxvf rarlinux-3.8.0.tar.gz
cd rar
./rar
./unrar
that all

and if u wanna unrar file
just write unrar ex.rar
like that

nb tht for centos 32bit
fot 64bit u should use
wget http://www.rarlab.com/rar/rarlinux-x64-3.9.3.tar.gz