A shell in Rust could be really cool

On the opposite I wrote some complex programs (thousands of lines to manage network configurations) in shell for the sole reason that they had to be maintainable *and fixable* in the field by their own users. This is one often underestimated value of the shell. Every user knows a little bit of it, can easily test manually in their terminal, adapt the changes to the script and try again.

A long time ago when I begun with unix, my default shell was tcsh. I didn't understand why some of my scripts didn't work the same way on the command line. I thought this had to do with interactive vs non-interactive. When I realized that the shell was different, I switched to bash and lost a lot of stuff (it was 1.14 by then), but I started to write working scripts. When 2.05b arrived scripting abilities improved a lot! I once tried to switch to zsh because it was compatible with bourne, but admins hated it due to the way it displays completion and moves the screen up. And one difficulty was that you quickly get used to features that again don't work in your portable scripts. So I went back to bash, the (in)famous bug-again-shell that everyone loves to hate. But in the end, scripts written with it work basically everywhere. And if you need to get rid of it because you end up with a real bourne (like dash), that's not that dramatic, you spend a few hours getting rid of bashisms and that's done. Or the user installs bash or ksh, since their compatible subset is quite large.

That's why people continue to write (sometimes long) shell scripts: that's easy, portable and transferable to someone else to take over them. And they come with basically 0 dependencies (aside external programs) so that makes them future-proof contrary to many interpreted languages whose interpreter breaks compatibility, or whose libraries love to change API all the time by adding a new argument to a function...