I remember a few years ago poking at julia and thinking it would make a really good shell language. The thing that killed it for this use at the time was slow startup; is that better now?
Much better, it's certainly worth giving it another go. It's still much slower than Python, but it's quick enough that I don't notice it all.
$ time julia -e 'println("Hi")'
Hi
real 0m0.241s
user 0m0.216s
sys 0m0.196s
$ time python3 -c 'print("Hi")'
Hi
real 0m0.046s
user 0m0.020s
sys 0m0.000sInspired me to install and try; about 350ms on my macbook pro. Much better than it used to be, but still more than you'd want for everyday commands (at least if you're picky about having your computer feel responsive, which I am). :-)
I did use fish a bit as a script language, but I decided for anything of any size I much prefer Julia. For typical file system navigation, fish is better, but Julia is actually pretty decent as a shell, despite being a real language. So writing shell scripts in it is pretty nice.
In the beginning I wrote separate programs executed from fish shell. But now I just fire up Julia as a shell and run functions directly there interactively.