Not very. Most notably `env -S` doesn't work on some systems. I did get bitten by one script on Ubuntu using uutils where the script expected `uname -p` to work but it just prints `unknown` (technically legal I guess). But when I went to fix it they already had.

Probably was a bit premature for Ubuntu to enable it by default. Looking at the graph uutils will be fully compatible (or as close as makes no difference) in about 2 years, so I would have waited until then.

Still, I think most of the push-back is just the usual anti-Rust luddites.

> expected `uname -p` to work but it just prints `unknown`

I just tried that on three very different Linux systems of mine, and all print `unknown`.

These utilities' purpose is to replace GNU utilities. BSD utilities' purpose is not.

Seems like there's more uproar with this than with changing the /bin/sh symlink to dash, and that difference seems much bigger.

To be fair, `/bin/sh` is suppose to be the POSIX shell, so as long as they are compliant it really doesn't matter. The problem with `/bin/sh` being bash, is that it provides extensions (even when running in POSIX mode from what I remember) and relying on them makes those scripts technically broken.

It would be more of a comparison if dash was aiming to be a drop-in replacement for bash and not a POSIX shell.

Well that's kind of my point. `ls` and `find` are "supposed to be" POSIX `ls` and `find`.

Obviously on a GNU system one can't just drop the GNU extensions, but what Rust Coreutils is fighting is (IIUC) to a large extent the goal of becoming bug-compatible, or unspecified-compatible.

For unspecified-compatible, to support users who relied on it (Hyrum's law), the same case could be made that lots of people relied on /bin/sh being bash.

dash may not have been aiming to be drop-in replacement for bash, but when OS vendors change /bin/sh to dash, what's the difference?

> Well that's kind of my point. `ls` and `find` are "supposed to be" POSIX `ls` and `find`.

I don't know about that, I at least wouldn't 100% agree on that. Mostly since POSIX only defines short args it kinda makes just not want to use them, since I like to spell out the long arg in scripts for clarity. So by default I just assume I am using GNU coreutils (since BSD coreutils have slightly different names in some places IIRC). And since there isn't such a destinction between "POSIX coreutils" and "GNU coreutils" like there is with "POSIX shell" (sh) and "bash" I wouldn't call the situations equivalent.

Ubuntu made /bin/sh dash in 2006 according to Wikipedia. Many fewer people used Ubuntu then.