diff --git a/scripts/tdp b/scripts/tdp
index 0e18dbf..7ddead9 100755
--- a/scripts/tdp
+++ b/scripts/tdp
@@ -147,7 +147,7 @@ set_pl () {
     fi
     if [ "$EUID" -eq 0 ]; then
       echo $(w_to_uw $2) > $pl_path
-    elif [ $gui_used == 1 ]; then
+    elif ! [ -z $gui_used ]; then
       sudo -A bash -c "echo $(w_to_uw $2) > ${pl_path}"
     else
       sudo bash -c "echo $(w_to_uw $2) > ${pl_path}"