Linux power statistics

power.sh

#!/bin/sh

echo "current   average   capacity   full_capacity   time_left"
factor=0.7
last_pwr=0
charge_full=`cat /sys/class/power_supply/BAT0/charge_full`
voltage_min_design=`cat /sys/class/power_supply/BAT0/voltage_min_design`
full_pwr=`echo "scale=5; $charge_full * $voltage_min_design / 1000000 / 1000000" | bc`
while [ 1 ]; do
    voltage_now=`cat /sys/class/power_supply/BAT0/voltage_now`
    current_now=`cat /sys/class/power_supply/BAT0/current_now`
    charge_now=`cat /sys/class/power_supply/BAT0/charge_now`
    voltage_now=`cat /sys/class/power_supply/BAT0/voltage_now`
    cur_pwr=`echo "scale=5; $voltage_now * $current_now / 1000000 / 1000000" | bc`
    if [ "$last_pwr" != "0" ]; then
        last_pwr=`echo "scale=5; $last_pwr * $factor + $cur_pwr * (1.0 - $factor)" | bc`
    else
        last_pwr=$cur_pwr
    fi
    rest_pwr=`echo "scale=5; $voltage_min_design * $charge_now / 1000000 / 1000000" | bc`
    time_left_h=`echo "scale=2; $rest_pwr / $last_pwr" | bc`
    echo $cur_pwr " " $last_pwr " " $rest_pwr " " $full_pwr " " $time_left_h
    sleep 5
done