Seriously. I do think people should spend enough time with bash or posix sh to be comfortable with it, but I'd recommend everyone at least just try fish. It's a lovely interactive experience out of the box with colors, completions, a great prompt, etc. Plus, the scripting language is quite comfy. Like, somewhere between bash and Python (if you find Python comfy, I guess). At least to me it makes more intuitive sense, once I got over the fact that "it's not bash/zsh."
It's written in Rust, if you care about that sort of thing (I switched before that was a thing). And for simple one-liners, compatibility actually has improved at least a bit (like you can do && now, which wasn't a thing before).
Write your shell-specific helper scripts or personal scripts in fish, write your portable scripts in Python or Bash. Look, I love standards. Sometimes non-standard things make sense though. Sometimes they even make more sense in the right context.
Or maybe you'll hate it. That's fine. People won't know until they try though.
For something newer and even more different, check out nushell. I don't have much experience with it, but a lot of its ideas are enticing.
The problem is that I forgot (if I ever knew) bash.
I can write fish, scripting or interactively on my shell without thinking too hard about the syntax, but when scripting in bash I require an example or using my snippets to be sure I'm not shooting myself on the foot or writing something that bash will reject right away.
The trick is to use "shellcheck" on your bash scripts, it's an overly anal linter that'll keep you sharp, and it's 2026, everyone can script bash with AI :)
But yeah the syntax with [[, if fi, while stmt; do; done, "$@", case esac, "${!VAR}" and others makes me long for the day fish shell gets "euo pipefail" mode so I can stop writing bash or || true :)
I think the last time that errexit and pipefail were brought up to the fish devs, we were treated instead to an essay about how errexit is a total hack in bash, how it has all kinds of places where it doesn't work as expected, how it's special-cased away for some constructs, etc. None of which is wrong, but it's still a whole lot better than the nothing that we have with fish now.
So we still have this inflection point where scripts eventually have to graduate into a "real" language, and while those languages give us proper data types and structures on one hand, they take away conveniences like pipes with the other. It's 2026, and we managed to crack artificial freakin' intelligence before we got a decently evolved shell into the mainstream. </yells-at-cloud>
Glad to see fish getting some shout outs here. Been using it for over ten years now, and it is super easy to get going on new hosts - it is just one simple install away.
