batrat

#!/usr/bin/env sh
#
# batrat - Detect switches from AC to BAT or viceversa and print them to stdout
# Rodrigo Campos <rodrigo@sdfg.com.ar>

# Creates the var BATS with a list of the paths to the BAT dir in
# /sys/class/power_supply/ and also creates the var ADPS with a list of the
# paths to the ADP dir in /sys/class/power_supply/
load_power_supplies() {
	for i in /sys/class/power_supply/*/type; do

		i_dir=$(dirname $i)
		i_type=$(cat $i)

		if [ "$i_type" = "Battery" ]; then
			BATS="$BATS $i_dir"
		fi
		if [ "$i_type" = "Mains" ]; then
			ADPS="$ADPS $i_dir"
		fi
	done
}

# sets running_on
detect_curr_supply() {
	load_power_supplies
	running_on="BAT"

	for ac in $ADPS; do
		if [ $(cat ${ac}/online) -eq 1 ]; then
			running_on="AC"
			return
		fi
	done
}

supply_change() {
	detect_curr_supply
	echo $running_on

	while inotifywait -qq -e access /sys/class/power_supply/*/online; do
		detect_curr_supply
		echo $running_on
	done
}

supply_change