My personal keyboard layout switcher: nix-env -iE "$(curl -sL https://git.io/fjvfP)"

me-keyboard-layout.nix

#! /usr/bin/env -S nix-env -if
{ pkgs ? import <nixpkgs> {}, ... }:

let 
  norman-layout = pkgs.fetchurl {
    url = "https://gist.githubusercontent.com/rehno-lindeque/ad5fef21f15ad13a9a355bbbd41fdc0a/raw/aa7948603ee266bd2a0bb6c9778ae7dd8bd1eccb/xmodmap.norman";
    sha256 = "14a63as7i35g6gkf0sqb324ck9k61w1vsdnz30sf8svnp4c0wjgq";
  };
in
{
  norman = pkgs.writeScriptBin "norman" ''
    ${pkgs.xorg.xmodmap}/bin/xmodmap ${norman-layout}
  '';
  jlimaj = pkgs.writeScriptBin "jlimaj" ''
    ${pkgs.xorg.xmodmap}/bin/xmodmap ${norman-layout}
  '';
  qwerty = pkgs.writeScriptBin "qwerty" ''
    ${pkgs.xorg.setxkbmap}/bin/setxkbmap us
  '';
  qwdfkj = pkgs.writeScriptBin "qwdfkj" ''
    ${pkgs.xorg.setxkbmap}/bin/setxkbmap us
  '';
}