Unfortunately it it probably Windows, just so he can run .bat scripts.

BatOS obvs

I would guess the Batcave uses something proprietary based off of Wayne tech because he's very paranoid. I'd also imagine it integrates some watch tower tech which is likely mostly from Cyborg

I imagine at least one modern version of the origin of the Wayne family fortune is through the tech industry. So clearly it would run Wayne-dows.

It’s a Unix system. I know this.

Hannah Montana, like all crimefighters

Ahhhh, iirc, it's one he built himself.

It's actually come up in comics before, more than once if my mind isn't playing tricks.

I don't doubt that he would have at least taken lessons from open source type projects if Linux doesn't directly exist in the comic universe.

Either a custom "BatOS," or, more likely, something branded under WayneTech. Which, in my mind, either way would be a weird, unholy, but utterly fantastical combination of Linux, Windows and MacOS.

Because it's a comic book and would show off whatever element of those systems it needs to in the moment for exposition or a gag.

For the German speakers under us: Wayne interessierts...

(As an explanation: Wayne sounds very close to the German "wen", meaning roughly "who". So that's a common joke phrase in German and means "Who cares?")

Well, according to one really bad video game, it's a late 90s mac.

but I like thinking that Batman is a Linux user. specify Arch

Nope, we can rule that out. Batman would have told us about it by now.

QNX. Batman does not abide service interruptions or system instability.