A shell script used to detect the battery power on Linux laptop and give a warning when the battey is low.

system-autodetect-battery-and-hibernate.sh

#!/bin/sh
# system-autodetect-battery-and-hibernate
# a shell script used to detect the battery power on Linux laptop and give a warning when the battey is low.
# License: MIT License
# Author: Yoxem Chen
# Date: 2019-11-10 (modified: 2019-11-11)


CRITICAL_PERCENTAGE=5 # in percentage

IS_LOWER_THAN_CRITICAL=false;



# get the current status "charging" or "discharging"
STATUS=`upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep state: | sed 's|[[:space:]]\+state:[[:space:]]\+||g'`;
# get the curreng battery usage
BATTERY_PERCENTAGE=`upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep percentage: | sed -e 's/[[:space:]]\+percentage:[[:space:]]\+\([0-9]\+\)%/\1/g'`;

if [ "${STATUS}" = "discharging" ] && [ "$BATTERY_PERCENTAGE" -lt "$CRITICAL_PERCENTAGE" ]; then
    IS_LOWER_THAN_CRITICAL=true;
else
    IS_LOWER_THAN_CRITICAL=false;
fi

if [ $IS_LOWER_THAN_CRITICAL = true ]; then
    DIALOG_TEXT="目前電量 ${BATTERY_PERCENTAGE}% 低於危險值 ${CRITICAL_PERCENTAGE}% ，以下將進行休眠動作。";
    zenity --warning --text="${DIALOG_TEXT}"; # show a warning dialo.
    gksu pm-hibernate;
fi