ruby code to detect non-ascii characters in files

find_chars.rb

index = 0
str.each_char do |char|
  index += 1
  unless char.ascii_only?
    puts "char at #{index} == ***#{char.inspect}***"
    puts str.slice(index - 10, 20)
  end
end

find_files.rb

Dir.glob('**/*.{java,js,html,txt}').each do |filename|
  contents = File.read(filename)
  puts filename unless contents.ascii_only?
end