[themerone]

I've seen people use IPC to workaround the GPL, but I've also seen the FSF interpretations claiming that is still a derived work.

I don't know if this has ever been tested in court.

[woadwarrior01]

My interpretation of their FAQ[1] on it is that shelling out and IPC are fine, while linking is not. As you say, it's ultimately up to the courts to decide on.

[1]: https://www.gnu.org/licenses/gpl-faq.html#MereAggregation