Did AT&T actually tried to enforce this copyright? Because what I see is auto-generated header that is put to every shell script present on the system. Entertaining nonetheless.
After the "insert copyright headers in all files" edict is given, it isn't unusual to find empty files that are copyrighted. Config files placeholders in particular end up copyrighting the zero length file.
I worked at a company that didn't merely issue this edict, but attempted to enforce it technologically. Every file in every commit was checked for the presence of a prescribed style of copyright string (something along the lines of "Copyright (c) YYYY Acme Inc.").
For a lot of my time there, I was more operations than development. A lot of piddly-ass configuration files and other things no copyright could possibly exist for got copyright strings added just so I wouldn't have to remember to type "NO ACME COPYRIGHT" into every bloody commit message to bypass the hook.
One of the issues in the AT&T versus UC BSD lawsuit was that AT&T forgot to copyright many of their files. (This was before automatic copyright.) So they probably over-reacted and went out of the way to label everything.
That's the C runtime starting up and finishing. That amount of overhead is incurred by (nearly) any program; in fact, worse overhead is incurred using the Sun method of having an empty file, because you have to run the more complex /bin/sh (or equivalent) instead of just a trivial compiled program.
ltrace gives a better view of what the program itself (as opposed to the runtime) is doing.
This is GNU's Appropriate Legal Notices as required by section 5d of the GPLv3:
An interactive user interface displays "Appropriate Legal Notices"
to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2)
tells the user that there is no warranty for the work (except to the
extent that warranties are provided), that licensees may convey the
work under this License, and how to view a copy of this License. If
the interface presents a list of user commands or options, such as a
menu, a prominent item in the list meets this criterion.
How can we know? A mere veiled threat of litigation is enough to make a lot of corporations cower in fear, and stop doing whatever generated the threat. Does merely threatening a suit constitute "enforcing the copyright"?
