#!/bin/sh

#
# Shuts down the computer when the battery reaches its warning capacity.
#
# Any modern battery needs to discharge from time to time in order to keep
# it in the best possible working state. Since it is annoying to stare at
# a screen, only waiting for the "your battery is on low capacity"
# message, this script was created. Just run it (as root) and it will
# automagically shut down your computer when the battery reaches its
# warning capacity.
#
# By default BAT0 (the main battery) is monitored. If you want to monitor
# an other battery pass its name (e.g. BAT1) as the first argument.
#
# This script is (c) 2010 Robert Weiler <http://digigeek.net/>. It is
# released under the terms of the MIT license.
#

if [ -z "$1" ] ; then
	BAT="BAT0"
else
	BAT="$1"
fi

if [ ! -d "/proc/acpi/battery/$BAT" ] ; then
	echo "Error: Cannot find the battery in /proc."
	exit 1
fi

BAT_WARN="`grep -E '^design capacity warn' \
		/proc/acpi/battery/$BAT/info | cut -c26- | cut -d' ' -f1`"
echo "Discharing until $BAT reaches $BAT_WARN mAh charge."

while [ /bin/true ] ; do
	BAT_CAPA="`grep -E '^remaining' /proc/acpi/battery/$BAT/state | \
			cut -c26- | cut -d' ' -f1`"
	if [ $BAT_CAPA -gt $BAT_WARN ] ; then
		echo "Capacity at $BAT_CAPA mAh. Waiting."
	else
		echo "Capacity at $BAT_CAPA mAh. Shutting down."
		/sbin/shutdown -h now &
		exit 0
	fi
	sleep 60
done

# vim: set sw=4 ts=4 noet ft=sh fenc=us-ascii ff=unix tw=74 :