diff -r -u powermgmt-base-1.33/on_ac_power powermgmt-base-1.33+whitespace/on_ac_power
--- powermgmt-base-1.33/on_ac_power	2018-03-12 02:51:32.000000000 +0200
+++ powermgmt-base-1.33+whitespace/on_ac_power	2019-02-18 13:23:33.292489081 +0200
@@ -25,11 +25,11 @@
 if [ -d /sys/class/power_supply/ ]; then
     for FN in /sys/class/power_supply/*; do
 	if test -d "${FN}" && test -r "${FN}/type"; then
-	    type="$(cat ${FN}/type)"
+	    type="$(cat "${FN}/type")"
 	    case "${type}" in
 	    Mains|USB*|BrickID)
 		if [ -r "${FN}/online" ]; then
-		    online="$(cat ${FN}/online)"
+		    online="$(cat "${FN}/online")"
 		    [ "$online" = 1 ] && exit 0
 		    [ "$online" = 0 ] && OFF_LINE_P=yes
 		fi;;