@Burn @ryo @digdeeper It must be absurdly rare. Growing up with Linux is rare even in countries where Linux is much more common. I looked it up, and some charts say that about 2% of the population of Japan uses Linux. How many of them use it for personal computers, I don't know, but presumably not many, because even that sounds like it may be too high. But the people that actually grew up with it may be 1% of that 2%, and also, I think fewer people in Japan use actual computers. Maybe still not more rare than growing up with BSD anywhere else. No idea.

But in Japan BSD seems to be comparatively less rare, to the point that FreeBSD and NetBSD even have Japanese websites. The chart that includes more OSs doesn't say the percentages, or even what the OSs are, but I assume that the one after Linux in size is FreeBSD, and it looks like it should be about 1.5%, and assuming that the next one is NetBSD, the two combined surpass Linux. This looks old, though, since it has Windows 10, but not 11, and 7 is still way more popular than 10, which has probably changed. I also think Linux probably got a little more popular just like it did everywhere else, though probably not quite as much.