$ sudo apt-get update
$ sudo apt-get install rt4-apache2 

rt4-apache2 is installed in your system.

Make ensure the rt4-apache2 package were installed using the commands given below,

$ sudo dpkg-query -l | grep rt4-apache2 *

You will get with rt4-apache2 package name, version, architecture and description in a table

rt4-apache2 package basic information: