Usage

invalidator = CloudfrontInvalidator.new(AWS_KEY, AWS_SECRET, CF_DISTRIBUTION_ID)
list = %w[
  index.html
  favicon.ico
]
invalidator.invalidate(list) do |status,time|   # Block is optional.
  invalidator.list                              # Or invalidator.list_detail
  puts "Complete after < #{time.to_f.ceil} seconds." if status == "Complete"
end

$ cloudfront-invalidator invalidate $AWS_KEY $AWS_SECRET $DISTRIBUTION_ID index.html favicon.ico
$ cloudfront-invalidator list $AWS_KEY $AWS_SECRET $DISTRIBUTION_ID
$ cloudfront-invalidator list_detail $AWS_KEY $AWS_SECRET $DISTRIBUTION_ID