Fetch IP via a bash command and/or input

[blankoworld]

Sometimes Internet is not needed to fetch our current IP. For an example our ISP gives the IP via an API on the router. That's why we could probably either fetch the IP with a bash command as here or a command input, for an example:

echo "1.2.3.4" | gandi-live-dns -i

as here

What's your opinion?