diff --git a/docs/Getting Started/NixOS/index.rst b/docs/Getting Started/NixOS/index.rst
index 9529601..d11e7a8 100644
--- a/docs/Getting Started/NixOS/index.rst	
+++ b/docs/Getting Started/NixOS/index.rst	
@@ -42,7 +42,7 @@ Live image ships with ZFS support by default.
     { config, pkgs, ... }:
 
     { boot.supportedFilesystems = [ "zfs" ];
-      networking.hostId = "$(head -c 8 /etc/machine-id)";
+      networking.hostId = (builtins.substring 0 8 (builtins.readFile "/etc/machine-id"));
     }
     EOF