$ sudo apt-get update
$ sudo apt-get install netrek-client-cow 

netrek-client-cow is installed in your system.

Make ensure the netrek-client-cow package were installed using the commands given below,

$ sudo dpkg-query -l | grep netrek-client-cow *

You will get with netrek-client-cow package name, version, architecture and description in a table

netrek-client-cow package basic information: