Get OS X Bluetooth device's battery from the command line

battery.rb

#!/usr/bin/env ruby
require 'plist'

def visit(thing, want, &block)
  case thing
  when Hash
    thing.keys.each do |key|
      if want.include?(key)
        yield key, thing[key]
      else
        visit thing[key], want, &block
      end
    end
  when Array
    thing.each do |value|
      visit value, want, &block
    end
  end
end

plist = Plist::parse_xml(`ioreg -c #{ARGV[0]} -a`)

props = {}
visit plist, ["BatteryPercent", "Product"] do |key, value|
  props[key] ||= value
end

p props

gistfile1.txt

➜  ~  ./battery.rb AppleBluetoothHIDKeyboard
{"BatteryPercent"=>49, "Product"=>"Tatsuhiko Miyagawa’s Keyboard"}
➜  ~  ./battery.rb BNBTrackpadDevice
{"BatteryPercent"=>39, "Product"=>"Tatsuhiko Miyagawa’s Trackpad"}

👍 https://github.com/miyagawa/btbattery