Battery stats

battery.rb

#!/usr/bin/env ruby
#
# Read battery event file and return some numbers

require 'json'

stats = {}
File.open("/sys/class/power_supply/BAT1/uevent", File::RDONLY) do |f|
  while(line = f.gets)
    (key, value) = line.chomp.split('=')
    value = value.to_i unless value =~ /\D+/
    stats[key.downcase.gsub("power_supply_", "").to_sym] = value
  end
end

case ARGV[0]
when "status"
  puts stats[:status]
when "charge"
  puts stats[:charge_now] / (stats[:charge_full_design] / 100)
else
  puts stats.to_json
end