[JoshMcguigan]

Thanks for pointing out `package.provided`. It does look like it could be a reasonable way to do this, but I'm not sure how exactly I'd be able to atomically swap GNU coreutils for uutils coreutils using that method?

I think I'd need to add `sys-apps/coreutils` to `package.provided`, then install uutils coreutils while telling Portage to ignore file collisions (because I'd be overwriting GNU coreutils binaries). However, that would have hidden the fact that I would have also been overwriting binaries from other packages (for example `hostname`, which is provided by `sys-apps/net-tools` in Gentoo).

[M95D]

packages.provided only bypasses the dependency issues. File collisions is a different problem with different solution(s). For a quick test, if I had to do it, I would probably make the ebuild install uutils in /usr/local/, then unmerge coreutils (and probably have a static busybox on stand-by, just in case).