add bluetooth_battery.sh script

bin/bluetooth_battery.sh

@@ -0,0 +1,15 @@
+#! /bin/bash
+
+name="$1"
+
+model_line=$(upower -d | grep -n "$name" | cut -d ':' -f 1)
+if [[ "$model_line" == "" ]]; then
+	exit 1
+fi
+
+idx=$(($model_line - 2))
+id=$(upower -d | sed "$idx!d" | awk '{print $2}')
+
+percentage=$(upower -i "$id" | grep "percentage: " | awk '{print $2}')
+
+echo "$percentage"