I will let others respond with specifics, but that was there in v5 at least.

One of the many shocks I had on arrival at Google was that in production, fd2 was pretty much standard output, as all the logging went there. And since our machines were still 32-bit CPUs then, it was common to overflow the offset because the logging output was, well, not parsimonious. It felt like I'd entered bizarro world, until I realized that few anywhere really knew how Unix was supposed to be used. And they still don't, and never will.

-rob

On Sat, Jan 21, 2023 at 9:46 AM ron minnich <rminnich@gmail.com> wrote:

I am trying to remember when fd 2 (aka stderr) became a thing. I have a vague memory that it was post-v6 but that may be way off.