[minetest2048]

You can have ads in a terminal / CLI, for example Ubuntu put an ad for their Ubuntu Pro service when you run sudo apt upgrade: https://linuxiac.com/ubuntu-once-again-angered-users-by-plac... . But the worst thing they can do is to show a plain text

[embedding-shape]

I remember some ops back in the day putting ads into /etc/motd (https://en.wikipedia.org/wiki/Message_of_the_day) for free/cheap servers/services too, 2-3 decades ago.

[Jblx2]

We'll they could also send your terminal a 0x07. And let me introduce you to ASCII art:

https://en.wikipedia.org/wiki/ASCII_art