Here's Linus's actual words: > anything that was written with Linux in mind (whether it then also works on other operating systems or not) is clearly partially

Here's Linus's actual words: > anything that was written with Linux in mind (whether it then also works on other operating systems or not) is clearly partially a derived work > Historically, there's been things like the original Andrew filesystem module: a standard filesystem that really wasn't written for Linux in the first place, and just implements a UNIX filesystem. Is that derived just because it got ported to Linux that had a reasonably similar VFS interface to what other UNIXes did? > Personally, I think that case wasn't a derived work, and I was willing to tell the AFS guys so. If we take this logic and apply it to this situation, we can see that the GPL always applies if you are intentionally designing for and using GPLed code in your program, even if you "run on separate machine and you talk to it over IPC". Now, if there happened to be some common readline API, with readline_gpl.so and readline_mit.so, then you could use it. But making up a hypothetical about readline_doesnotexist.so, when the only implementation you actually are using is readline_gpl.so is not going to convince a judge that the GPL does not apply. You could maybe get away with it if you originally designed for inputline.so, some non-GPL library that had similar functionality to readline but with a different API, and then ported to readline.so - it would be situation dependent and I'd probably talk to a lawyer here. However, that wasn't what happened here either.