But if you seek to replace coreutils (as at least is the case with Canonical it seems), rather than just be another POSIX userland implementation (e.g. busybox), then I would suggest you do need to be bug-compatible? I can apt/dnf/apk install busybox and use that for my user rather than coreutils, but given a significant amount of Linux infrastructure (including likely many personal scripts) are tied to coreutils, the bar is much higher. Given the numerous issues with quality Canonical has had, not just with Ubuntu but their other "commercial" tooling, I'm not sure any rewrite/port, written in rust or otherwise, with Canonical developing, managing, or even being associated with the project can meet the requisite bar.