add backlight support

backlight

@@ -0,0 +1,12 @@
+#!/bin/bash
+DIR="/sys/class/backlight/"
+if [[ -d "${DIR}acpi_video0" ]]; then
+   DIR="${DIR}acpi_video0"
+elif [[ -d "${DIR}intel_backlight" ]]; then
+   DIR="${DIR}intel_backlight"
+fi
+cat "${DIR}/brightness" "${DIR}/max_brightness" | gawk '
+    NR==1 { cbr=$1 }
+    NR==2 { mbr=$1 }
+    END { printf("%d%", cbr/mbr*100) }
+'