diff --git a/etcnixos/system-nixos.nix b/etcnixos/system-nixos.nix
index 9ba0080..2b477b1 100644
--- a/etcnixos/system-nixos.nix
+++ b/etcnixos/system-nixos.nix
@@ -67,9 +67,11 @@
     let
       no-rgb = pkgs.writeScriptBin "no-rgb" ''
         #!/bin/sh
-        NUM_DEVICES=$(${pkgs.openrgb}/bin/openrgb --noautoconnect --list-devices | grep -E '^[0-9]+: ' | wc -l)
+        set -e
 
-        for i in $(seq 0 $(($NUM_DEVICES - 1))); do
+        NUM_DEVICES=$(${pkgs.openrgb}/bin/openrgb --noautoconnect --list-devices | ${pkgs.gnugrep}/bin/grep -E '^[0-9]+: ' | ${pkgs.coreutils}/bin/wc -l)
+
+        for i in $(${pkgs.coreutils}/bin/seq 0 $(($NUM_DEVICES - 1))); do
           ${pkgs.openrgb}/bin/openrgb --noautoconnect --device $i --mode direct --color 000000
         done
       '';