Running nix-shell would then drop you into a shell with these libraries and binaries available

{ pkgs ? import <nixpkgs> {} }:

(pkgs.buildFHSUserEnv {
  name = "simple-x11-env";
  targetPkgs = pkgs: (with pkgs;
    [ udev
      alsaLib
    ]) ++ (with pkgs.xorg;
    [ libX11
      libXcursor
      libXrandr
    ]);
  multiPkgs = pkgs: (with pkgs;
    [ udev
      alsaLib
    ]);
  runScript = "bash";
}).env

From Nixpkgs manual

Help me find this in the bin inventory on the 21.05 OS.

Help me find this in the bin inventory

NixOS doesn’t have a traditional bin dir. What are you trying to achieve?

Yea I know the /bin/start.shjust trying to see if relative paths are supported.