What if I take the source code for "ls", turn it into a library, so that I could do the same thing but more directly -- the library is obviously a derivative work, but would my program that calls it also be a derivative? (note, in this case the hypothetical library would be GPL, not LGPL).
And, if I want to link to a GPL (not LGPL) library, if I write a wrapper for it that turns it into a stand-alone executable (sort of like how you can call openssl functions, or you can run the openssl executable passing command line arguments), does one form of calling create a derivative and the other form not?
No, output of a program isn't the program itself, so it doesn't fall under copyright[1]. Why would you expect that it would be a derivative work? It should be obvious that e.g. when gcc outputs a compiled program it doesn't automatically become tied to the GPL.
The only exception - which is mentioned[2] in the GPL - is if the output of a GPL licensed program is part of the licensed program. (quines, other rare utilities)
2. Basic Permissions.
[...] This License explicitly affirms your unlimited permission
to run the unmodified Program. The output from running
a covered work is covered by this License only if the output,
given its content, constitutes a covered work. [...]
Probably[3], but see the FAQ[4] for answers to common situations and a real lawyer for actual legal advice.
> does one form of calling create a derivative and the other form not?
Correct. They are different. The intent is that the GPL licensed code is still open. Users that receive copies of the new stand-alone executable can exercise their right to examine and modify that code. They can easily replace it with a version they have modified without touching your other programs that merely use the output.
[1] https://www.gnu.org/licenses/gpl-faq.html#GPLOutput
[2] https://www.gnu.org/licenses/gpl-3.0.en.html
[3] https://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL
My point, however, wasn't these specific scenarios, I was using them as examples as examples in response to the parent's comment inferring that you know exactly what it means. "Consult a lawyer" kind of just reinforces the point.
Of course, I do agree that most community licenses such as the GPL are infinitely more readable than most proprietary software licenses.
This is why I firmly believe the only way out of this mess is an international standard of common "service / license guarantees" and "terms and services" and hell, even "privacy policies" patterns that can be reused across software and services to immediately illuminate freedoms, limitations, and guarantees.