A simple script to format the output from `pmset -g batt` into a row of stars and icons.

battinfo.rb

#!/usr/bin/env ruby
# encoding: utf-8
full    = "★"
empty   = "☆"
battery = "🔋"
plug    = "⚡"

  star_count = 5 
per_star = 100/star_count

v= Hash.new()

ARGF.each do |a|
  if a.start_with? "Now"
    #test for the first line
    if a =~ /'(.*)'/
      v[:source] = $~[1]
    else
      v[:source] = ""
    end
  elsif a.start_with?" -"
    if a =~ /(\d{1,3})%;\s(.*);\s(\d:\d{2}|\(no estimate\))/
      v[:percent] = $~[1].to_i
      v[:state]   = $~[2]
      v[:time]    = $~[3]
    else
      v[:percent] = "0"
      v[:state]   = "unknown"
      v[:time]    = "unknown"
    end
  end
end
outstring = ""
if v[:source]== "Battery Power"
 outstring += "#{battery}  " 
else
  outstring +="#{plug}  "
end

full_stars  = v[:percent]/per_star
empty_stars = star_count - full_stars
full_stars.times  {outstring += "#{full} "}
empty_stars.times {outstring += "#{empty} "}

outstring += v[:time] == "0:00" ? " charged" : " #{v[:time]}"

puts outstring

this had to be updated for Mavericks, because the language that comes out of pmset has changed.

./battinfo.rb:41:in <main>': undefined method/' for "0":String (NoMethodError) is occurred when I try to run the pmset command on terminal manually....The line causing error is
full_stars = v[:percent]/per_star