Truthfully, I’ve not tried them.

I was about to make a comment along the lines of “I’ve already learned how to do command line things, my OS already comes with a few shells, why SHOULD I take the time to learn a new shell?” — but then I reflected on this and realized something: it’s the same thing as saying “Windows comes with Explorer/Edge, why SHOULD I go through the trouble to pick up a new web browser?” And yet, I unquestioningly download Firefox first thing when I install a new OS, hmm.

You’ve made me think :]

Fish is slowly adding more POSIX syntax, e.g. $(cmd), export ENV_VAR=1 and CFLAGS=-02 make now work as you would expect.

Looks like the latest version streams output from one command to the other. For example, when I run for i in (seq 1 5); sleep 1; echo $i; end | cat I see the numbers show up one at a time.

It is because it departs from POSIX that it is good; I recognize the syntax for some functionality is cumbersome and hard to remember though. There are similarities like command names and piping still…

I use NixOS and home-manager, so for switching I just

  home-manager.users.yuu = {
    programs.nushell = {
      package = pkgs-update.nushell;
      enable = true;
      configFile.source = ../../config/nushell/config.nu;
      envFile.source = ../../config/nushell/env.nu;  
    };
  };

The config.nu and env.nu is basically the default just with a customized prompt.

Then in my alacritty.ylm I set shell to the nu binary

shell:
  program: /etc/profiles/per-user/yuu/bin/nu

Also learned from official resources https://www.nushell.sh/book. When I have doubts, I ask either on Nushell’s GitHub discussions or https://matrix.to/#/#nushell:matrix.org

And to keep a POSIX shell

{
  environment = {
    systemPackages = with pkgs; [
      mksh
    ];

    sessionVariables = rec {
      TERM = "alacritty";
      TERMINAL = "alacritty";
      SHELL = "${pkgs.mksh}/bin/mksh";
    };

  environment.shells = [
    "${pkgs.mksh}/bin/mksh"
  ];
}