Rewriting the GNU Coreutils in Rust

Yes, I'm well aware of that, and I was going to add a second paragraph repeating the conventional wisdom that rewriting from scratch isn't always a good idea, but since this is LWN I assumed an educated audience wouldn't need the reminder.

I agree with Joel's points, and you don't want to ditch battle-hardened code, but if the hardening was only added for running on AIX 0.9 in mixed-endian EBCDIC configuration, you can drop it as long as you explicitly drop support for that platform. A new implementation with narrower goals doesn't have to be a drop-in replacement for the old version in all cases. And there are times when rewriting is worthwhile; the GNU tools themselves are from-scratch rewrites of classic Unix utilities, and quite apart from licensing they fixed lots of technical problems like fixed line width.