[goto11]

I do understand what a REPL is and have even used one from time to time. But from my perspective, a program which cannot interact with the outside world is literally useless.

It is not an accident that almost any tutorial for any language or framework or platform starts with "hello world". Because you want to start with the minimal but real, working program - and build from there.

[dllthomas]

I seriously don't see how a stand-alone "hello world" program is meaningfully "interact[ing] with the outside world" in a way that printing a string at the REPL is not. Stop ranting and posturing, and instead please try to unpack that.

In either case you are simply printing a string to the terminal. The standalone program is easier to compose in your shell, which in some contexts matters a lot, but I don't see that it does here. Where is the difference?

Further, if we define "interact with the outside world" in a way that excludes the programmer reading things off the screen, then it's plainly wrong that all such programs are "literally useless". Calculators, for instance, have delivered a tremendous amount of value. I've personally run something at a REPL (in various languages) plenty of times because I had actual use for the value to be printed and didn't need to persist the program.

[goto11]

The point of "Hello world" is that it is the simplest possible real, working program. It can be compiled and executed and you could deploy it to users or to a production environment if you wanted.

"A complex system that works is invariably found to have evolved from a simple system that worked."

I understand that from a certain theoretical perspective it is just the same thing to echo a string literal in a REPL, but from a software development perspective it is completely different.

> The standalone program is easier to compose in your shell, which in some contexts matters a lot, but I don't see that it does here.

I kind of see where you are coming from. You are assuming the program is only ever used by yourself. I understand this is just a different culture and hadn't even thought about that perspective.