reason I asked was my memory was #! in 1978 or so. But that's now sounding like I compressed time a bit.
Sounds a little early for my memory for the kernel, but about right for the support using the shells. I would have thought we talked about the idea at the Summer '79 USENIX and later Dennis implemented a patch for Research Unix which it looks like he released it in early 1980. But if I'm not getting my dates wrong, that should have been before 3BSD was released for the Vax; which syncs with my memory that it was in 3BSD. Due to address space issues on the 11, add features to the kernel that we could do in userspace, was often the preferred place. I just don't remember if Joy had it in the 2BSD kernel before Dennis added it to the research kernel, but I do remember it was in shells @ UCB as Jeremy said much earlier.