new_contents: #!/usr/bin/env python
  # coding=UTF-8
  #
  # http://stevelosh.com/blog/2010/02/my-extravagant-zsh-prompt/
  
  import math, subprocess
  
  p = subprocess.Popen(["ioreg", "-rc", "AppleSmartBattery"], stdout=subprocess.PIPE)
  output = p.communicate()[0]
  
  o_max = [l for l in output.splitlines() if 'MaxCapacity' in l][0]
  o_cur = [l for l in output.splitlines() if 'CurrentCapacity' in l][0]
  
  b_max = float(o_max.rpartition('=')[-1].strip())
  b_cur = float(o_cur.rpartition('=')[-1].strip())
  
  charge = b_cur / b_max
  charge_threshold = int(math.ceil(10 * charge))
  
  # Output
  
  total_slots, slots = 10, []
  filled = int(math.ceil(charge_threshold * (total_slots / 10.0))) * u'▸'
  empty = (total_slots - len(filled)) * u'▹'
  
  out = (filled + empty).encode('utf-8')
  import sys
  
  color_green = '%{[32m%}'
  color_yellow = '%{[1;33m%}'
  color_red = '%{[31m%}'
  color_reset = '%{[00m%}'
  color_out = (
      color_green if len(filled) > 6
      else color_yellow if len(filled) > 4
      else color_red
  )
  
  out = color_out + out + color_reset
  sys.stdout.write(out)
  
subject: Add Steve Losh's script to display battery status on OS X