encodings = []
not_utf8 = []

Dir.glob(Dir.new(".").path + '/**/*.rb') do |file|
  contents = File.read(file)
  detection = CharlockHolmes::EncodingDetector.detect(contents)
  encodings << detection[:encoding]
  not_utf8  << {file: file, detection: detection}  unless "UTF-8" == detection[:encoding]
end

pp encodings.uniq

pp not_utf8