Creating an alternative UI is rather uncontroversial. The plumbing doesn't need replacement. Jujutsu for example, seems to be popular.

Note that Jujutsu is not exactly a frontend for Git (it is only loosely coupled to Git) -- Git is one of at least two backends for Jujutsu.

Ha, replacement? You can't even get them to fix bugs. If you fix a bug in a unix command you'll break every script in existence and bring the world down. It's idiotic.

The user's a file! The internet's a file! Keyboard is a file! What are checkboxes? This is a volunteer project! You can't expect us to include UI in the OS! We'll just bikeshed forever so sorry, write your own, lol.

Getting a bug fixed in rsync, pulled down to LTS Ubuntu took a single email. I’m not sure what you are going on about.

Congratulations. You just broke userspace.

You clearly have no idea what you are chattering about. The saying "Don't break userspace" is for the kernel. It has nothing to do with userspace programs potentially affecting other userspace programs.

I found and fixed a bug in Debian’s vixie-cron where if the system time clock changed without restarting crond, it wouldn’t modify its runs until the next DST event.

This was well-received without complaint or concern for breaking people’s [insane] workflows that may be relying on that behavior.

This describes all of programming. They are called dependencies and they tend to be versioned. Breaking changes affect literally every aspect of software development. Software that isn’t maintained will no longer function at some point in the future.

> as soon as scripts were allowed to use commands, those commands could never be changed

That's not a script thing, that's an API surface thing, and even then only applies to backwards-incompatible changes. You can change the arguments to git or chmod just as easily as printf() or fork()

As I said here already, the difference is that scripts are interpreted, rarely if ever check what version they're running on before they attempt to do something, and the authors of the scripts have been explicitly encouraged to memorize a heapload of letter permutations and throw a thermonuclear systemd-sized fit if something changes.

None of this is inherent to APIs.