diff --git a/brightness.sh b/brightness.sh
index 7973058..c592cb3 100644
--- a/brightness.sh
+++ b/brightness.sh
@@ -5,7 +5,7 @@
 # Version: 0.1
 ########################################
 
-[ $UID != 0 ] && echo -e "\033[1;31mERROR:\033[0m Need to be run as root!" >&2 && exit 1
+[ ${UID} != 0 ] && echo -e "\033[1;31mERROR:\033[0m Need to be run as root!" >&2 && exit 1
 backlight="/sys/class/backlight/intel_backlight"
 [ ! -d "${backlight}" ] && echo -e "\033[1;31mERROR:\033[0m No such file or directory: ${backlight}">&2 && exit 1