It makes far more sense in the context of effectively a remote session or dumb terminal serial connection. Your "terminal" application is only emulating a text mode environment inside a gui, typically... you can ctrl+alt+F2 - F5 in a lot of Liknux's to switch to a terminal session if you want, but that's not what people tend to actually use.

Beyond this, without remote X properly configured, again, most don't and probably shouldn't.. you aren't running remote gui applications over an SSH session. Richer TUIs were pretty common in ye old days of DOS and other OSes before rich GUIs become the norm. DOSShell, Edit.com, etc. The IDEs of days past and Word Perfect even. These all interacted with Mice and were considered the norm. The features that allow this over a remote terminal today are pretty great IMO, the harder part is properly handling window sizes/resizes, etc.

With graphical extensions, there are even nice app explorers with image previews via TUI. It pushes the boundaries. For that matter, I often wonder what could have come with RIPscrip/RIPTerm if the leap to web didn't happen the way it did...

I think the single hardest part of TUI is dealing with wide characters and secondary fonts for color emojii that don't quite render in 2 spaces completely in a lot of termianls... it makes the line drawing harder too.

In the Linux world, your GUI is built on a stack of separate programs. At the bottom is the "display server", such as X11 or Wayland. One of these needs to run to have GUI windows (or a full-screen background) at all; otherwise the screen is just covered by 80x24 terminal, and even if there were mouse support there would be nowhere to click or drag to change that. Without the display server, you are in a "text session". It's relatively rare to do this locally nowadays, but Linux still adheres to the highly modular UNIX philosophy.

Your terminal windows (whether that's "Terminal" or "cmd.exe" or anything else) are still fundamentally graphical programs that emulate such a text session.

Is it character mapped, designed to run in a tty terminal? TUI.

Is it pixel or vector mapped, designed to run in a graphics terminal? GUI.

Of course strictly speaking TUI is a subset of possible graphical user interfaces, but the term GUI was coined to denote interfaces other than the already-ubiquitous text terminal interfaces.

TUIs have since absorbed GUI interface elements like buttons, checkboxes, and even pointer input, which I think is causing the terminology complaint here. Classical TUIs like Norton Commander are more about keyboard input and navigation. But being text-mapped is the identifying feature of a TUI, I think most people accept.

Sometimes your system doesn’t have a graphical session, like a raspberry pi with no x server running, or a cloud compute instance I’m ssh’ed into, or a docker image running on my laptop. Sometimes your system doesn’t have a (particularly usable) text system, like a work computer that disables the terminal or a family member’s MacBook who doesn’t have the time or space to install XCode terminal utilities to be able to use things like brew install.

My point is that it’s not a given that having one means you have the other.

TUIs are wonderful for the first case.

Perhaps he's thinking about "console" / "display server" but the lines blur fast (e.g. you can run GUI in linux console with framebuffer with some limitations)

- https://en.wikipedia.org/wiki/Linux_console - https://en.wikipedia.org/wiki/Windowing_system#Display_serve...

It feels like a reference to DOS graphics mode.