nix-config/users/tacocat/shell/fish.nix

{...}: {
  programs.fish = {
    enable = true;
    interactiveShellInit = ''
      set -g fish_greeting

      fish_vi_key_bindings
      set -g fish_cursor_insert line

      if not set -q TMUX
        tmux attach
      end
    '';
  };
}