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Why Scènes À Faire Should Apply to Command-Line Interfaces

by Bradley M. Kuhn on January 3, 2018

Today, Conservancy joined other amici in the Cisco v. Arista case. Specifically, the amicus brief discusses why the scènes à faire affirmative defense for copyright infringement is appropriate and actually necessary regarding imitation of command-line interfaces. I hope this blog post will convince you that software freedom contributors should care about the issue.

The easiest example to understand these issues is Unix. Most of us know the basics of Unix's user interface, which primarily consists of commands that live in /bin and /usr/bin, that each include various command-line options that we've memorized. When the GNU project started, as RMS has described in his talks, he chose to imitate this user interface. Many reasons were obvious, but the most important one was that Unix was already an industry standard and users already knew its interface.

At the time, no one would have considered that you'd be liable for copyright infringement merely writing some new programs — 100% from scratch — that happened to have the same names and the same command-line options that were found in Unix. That interface, in fact, has been reimplemented at least a hundred times — by many Unix vendors and by various software freedom projects (GNU of course, but also by Conservancy's BusyBox project and others). As developers, we'd be incredulous if told that GNU infringed Unix's original copyrights. But that's exactly the argument that Cisco made about Arista's imitation of Cisco's command-line interface.

I'm not a fan of either Cisco nor Arista; all the software in question is proprietary software. Indeed, GitHub, which is one of our joined amici here, produces much proprietary software around Git, and that's bothers me too. I don't like it when any company writes proprietary software to work along with FLOSS. However, I agree with GitHub and Arista that copyright restrictions should not extend too far; copyright should not stifle simple command-line interoperatiblity. Merely imitating a command-line interface of one program in another should not cause (by itself) a copyright infringement.

Now, the last part to discuss are the questions: What is an affirmative defense, and what is scènes à faire? So, to explain it roughly with as little legalese (IANAL) as possible, an affirmative defense is one that you must prove after you're accused, usually through a trial (which is what occurred here). The burden is on the Defendant to prove that affirmative defense. (By contrast, if Arista had shown that, in fact, their command-line interface bore no similarity to Cisco's, that would have been a “negating defense”. Such defenses are much more assured to win, as they don't place such a burden on the defense.)

So, what, specifically, is the affirmative defense of scènes à faire? It's a concept originally from fictional works that generally expresses this idea: “if you're going to tell this story at all, you need at least these elements”. In this example, the analogy works like this: if your users will give a router textual commands via the command-line, that user will expect certain commands to work. Cisco's commands are industry standard and expected by users, similar to those in Unix. The amicus brief argues that this is a reasonable application of scènes à faire, because there is great benefit to the public and users if such imitation is permitted on command-lines without copyright restriction. Remember, under the USA Constitution, copyright exists as an “exclusive Right to … Writings” only because such exclusive controls “promote the Progress of Science and useful Arts”. Copyright is not an absolute right of control over written works by the authors, and its tentacles must be shortened by the public interest.

Finally, I call on the Linux Foundation to publicly ask their platinum member, Cisco, to stop this aggressive litigation on an edge case of copyright. Such a request would be consistent with the Linux Foundation's public criticism of others for copyright enforcement. This case is one where we all should stand together in the interests of free innovation.

Tags: conservancy, law

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