$ sudo apt-get update
$ sudo apt-get install libradiusclient-ng2 

libradiusclient-ng2 is installed in your system.

Make ensure the libradiusclient-ng2 package were installed using the commands given below,

$ sudo dpkg-query -l | grep libradiusclient-ng2 *

You will get with libradiusclient-ng2 package name, version, architecture and description in a table

libradiusclient-ng2 package basic information: