You're right. The GPL can't be applied in this way. However, there were a few attempts (accidental it was claimed) to do this back in the day, mostly by cutting and pasting bits out of NET2 for this or that GPL thing. I don't recall the specifics, since it was fixed like 25-odd years ago. Accidental, as claimed, or sneaky, the incidents (and talk of the incident) left a bad taste in people's mouths. A couple of times the code in question passed from one person to the next until the knowledge of the original copying was lost until discovered by someone who was familiar with the original sources and did a comparison. The reactions and the personalities didn't help to smooth over the ruffled feathers either. To be fair, it was a different time. The knowledge of what was and wasn't permissible simply isn't at all what it is today. For many people, it tended to fall into "OK to copy" and "NOT OK to copy". The nuances of license compliance did not have the benefits of the last two and a half decades of public education. While some people knew and respected, it wasn't as universal as it is today. So it was natural that people would just copy and not attribute. It didn't take too many incidents of that happening for the word to spread it wasn't cool and that just because you could copy an entire file w/o a problem doesn't mean you could cut a dozen routines out of it and paste it into your own work. That's why any projects that started out as a copy from BSD (or worse AT&T) were thoroughly reworked to expunge that taint and you don't hear about it today. It stopped being more than an incidental problem in the mid 90's. And it wasn't just BSD->GPL either, again to be fair, the same ignorance allowed code to flow the other way a time or two... Warner On Sat, Mar 18, 2017 at 7:27 AM, Nick Downing <downing.nick(a)gmail.com> wrote:

On Sat, Mar 18, 2017, at 12:25, Doug McIlroy wrote: The "calendar" available my Linux machine is from the "bsdmainutils" package (which has never been put under the GPL, incidentally) which is stuff copied with attribution from FreeBSD/NetBSD/OpenBSD, and calendar.c has a UCB copyright/license and OpenBSD RCS ID at the top of the file. (In the TUHS archive, this implementation first appears in 4.3BSD-Reno, with earlier versions having code clearly derived from V7). The earliest version (from Debian 1.1) that I can find has a UCB copyright dated 1993 and SCCS ID 8.3 3/25/94, not much removed from 4.4BSD in the archive (which has SCCS ID 8.1 6/6/93) - my guess is that the actual source is 4.4BSD-Lite, which is mentioned in the bsdmainutils README. In the converted-to-git CSRG archive, the implementation first appears in 1989 by "bostic" (Keith Bostic, presumably) https://github.com/weiss/original-bsd/commit/46857f6fe723eff85f22986beb7806… with the change note "redone from scratch as a C program to fix cpp security problem" - this is the first version to have a UCB copyright notice. [Using cpp seems to have itself been a BSD innovation circa 4.1cBSD] V7 calendar consists of a C program that outputs a set of regexes, and a shell script that runs egrep. Unless by "same quirky basic method" you mean the fact that it reads events from a text file at all, I'm not sure what you're referring to... but that's functionality rather than implementation. There's a lot of code in a handful of not-part-of-GNU-proper core utility packages used in Linux distributions - bsdmainutils, bsdgames, bsdutils, and util-linux [only the last of which has the GPL] - which come from some BSD or another and mostly have intact UCB copyright statements and licenses at the top. If any of these are improperly attributed, it's likely that UCB is to blame.