Unrar

Launch Synaptic Package Manager, search for unrar. You will get two available unarchiver unrar and unrar-free. Unrar-free come out with limited function compare with unrar (non-free version). It's up to you which unrar you want to install.

For me, I choose unrar (non-free version). Mark it for installation. Once completed, you will be able to view/unrar .rar file extension.

Install unrar using terminal;
root@support-t60:~# apt-get install unrar