In public space we can speak to ourselves, another person or to everybody. This latter kind of speaking is known as shouting.

On a computer network the equivalent comes in the form of ‘broadcast’ packets, sent to every single host (computer, smartphone, router) on the same network subnet you are on. Such packets are used to manage aspects of the network’s functionality or announce services such as network printer sharing.

Here is a command that will shout angrily at every device on the network you’re on, should you ever feel the need.

            echo "R R O O O O A A R R R R !"|socat - UDP-DATAGRAM:$(route -n|grep UG|awk \
            '{print $2}'|cut -d '.' -f1-3).255:5000,broadcast

Requires package socat and a GNU/Linux host.