s3_mass_bucket_delete.rb

require 'fog'

bucket      = 'bucket-name'
credentials = {
  :provider              => 'AWS',
  :aws_access_key_id     => 'access_key_id',
  :aws_secret_access_key => 'secret_key',
}

fog   = Fog::Storage.new(credentials)
files = fog.directories.get(bucket).files.map{ |file| file.key }
fog.delete_multiple_objects(bucket, files) unless files.empty?
fog.delete_bucket(bucket)