command-line calls of GPL'd executables

SamBC sambc at
Sun Jul 15 18:20:46 UTC 2001

IANAL, but I've hung around here long enough to know the consensus of a lot
of people. These people are mostly NAL either, but it's some idea.

> -----Original Message-----
> From: phil hunt [mailto:philh at]
> Consider this situation:
> Alice writes a program, aprog, which she licenses under the GPL.
> Bob writes another program, which invokes the aprog executable,
> using the POSIX system() call. Does Bob's program have to be
> released under a GPL-compatible license?
> (Assume for the sake of argument that there is no other program
> that does the same as aprog).

Bob is not linking. He would not be linking if he used system or exec*. All
that is happening is bob's prog is running the executable. After all, do you
have to have a GPL operating system to run GPL'd programs? No, is the short
answer. However, the running of the program must still conform to license

> What if aprog is, instead, licensed under the BSDL with advertising
> clause. Can be GPL his program?

This is slightly more knotty. Bob must abide by the license terms of aprog,
so if these terms include displaying 'adverts' when the program is run,
Bob's prog must still display these adverts.

IANAL, but this seems relatively clean-cut (as anything legal can be) to me.


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