$ sudo apt-get update
$ sudo apt-get install fusiondirectory-plugin-nagios 

fusiondirectory-plugin-nagios is installed in your system.

Make ensure the fusiondirectory-plugin-nagios package were installed using the commands given below,

$ sudo dpkg-query -l | grep fusiondirectory-plugin-nagios *

You will get with fusiondirectory-plugin-nagios package name, version, architecture and description in a table

fusiondirectory-plugin-nagios package basic information: