I have `users.defaultUserShell = pkgs.fish;` set on my server and when I ran `nixos-rebuild switch --target-host …`, the command failed with the following error:
fish: Unsupported use of '='. To run 'nix-store' with a modified environment, please use 'env PATH=… nix-store…'
That is because fish requires env to set environment variables for a program. It should also work on other shells.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.