terminal countdown timer

timer.rb

require 'time'

countdown_time = ARGV[0]
puts "-- Input Countdown time: XX:XX:XX ---" if !countdown_time
t = Time.parse(countdown_time)
seconds = (t.hour * 60 * 60 + t.min * 60 + t.sec).to_i

while (seconds!=0) do
	print " " + Time.at(seconds).utc.strftime("%H:%M:%S")
	print "\r"
	sleep 1
	seconds -= 1
end
puts "\n"

`say "Countdown End"` if /darwin/ =~ RUBY_PLATFORM