ruby script to check battery status

battery_info.rb

#!/usr/bin/env ruby
# coding: utf-8

require 'highline'

def ac_status
  print "AC: "
  if open("/sys/class/power_supply/AC/online", 'r').read.to_i == 1
    puts "Online"
  else
    puts "Offline"
  end
end

def battery_info(id, linewidth = HighLine::SystemExtensions.terminal_size.first)
  barwidth = linewidth - 28 - 1
  info = {}
  open("/sys/class/power_supply/BAT#{id}/uevent", "r").each_line do |line|
    key, value = line.split("=")
    info[key.sub(/^POWER_SUPPLY_/, "")] = value.chomp
  end

  puts "#{info["NAME"]}: #{info["ENERGY_FULL_DESIGN"].to_i / 1000000.0}Wh #{info["TECHNOLOGY"]} battery (#{info["MODEL_NAME"]} by #{info["MANUFACTURER"]})"

  ratio_design = info["ENERGY_FULL"].to_f / info["ENERGY_FULL_DESIGN"].to_f
  print "  design ["
  print "#" * (barwidth * ratio_design).to_i
  print " " * (barwidth - (barwidth * ratio_design).to_i)
  printf("] %5.1fWh (%5.1f%%)\n", info["ENERGY_FULL"].to_f / 1000000.0, ratio_design * 100.0)

  ratio_charge = info["ENERGY_NOW"].to_f / info["ENERGY_FULL"].to_f
  print "  charge ["
  print "#" * (barwidth * ratio_charge * ratio_design).to_i
  print "." * (barwidth - (barwidth * ratio_charge * ratio_design).to_i - (barwidth - (barwidth * ratio_design).to_i))
  print " " * (barwidth - (barwidth * ratio_design).to_i)
  printf("] %5.1fWh (%5.1f%%)\n", info["ENERGY_NOW"].to_f / 1000000.0, ratio_charge * 100.0)
end

ac_status

Dir.glob('/sys/class/power_supply/BAT*').size.times do |id|
  battery_info id
end