On Linux, you’ll want to install figlet and toilet (both available in the debian repos)
Alternatively you’ve got this online frontend
If you really want to get weird with it you can also play any video in ascii art through libcaca and mplayer. Looks like this
I use Arch btw Endeavour OS so don’t have Debian repos but I will definitely check them out. I especially like the fancy dark mode.
I just checked and figlet at least appears to be in the arch repositories as well
it’s typically just a kind of pixel art with monospaced fonts¹. any characters you see that’s not typically shown on your keyboard (e.g a filled square) can be found in a character selection program in your OS. anything else related to texts, templating and line breaks you can probably find a program somewhere on places like crates.io or gitlab or write something of your own without much trouble.
¹ a monospaced font is a font where every letter and character has the same spacing from each other, and are the easiest to do ascii art. (ascii is just one character table, but you can also gather unicode chars all you want)
