This doesn't work. It says everything is a unix newline.

count_newlines.rb

def report_newlines filename, io
  windows_newlines = 0
  unix_newlines = 0
  last_line_is_bare = false
  while line = io.gets
    last_line_is_bare = false
    if line =~ /\r\n$/
      windows_newlines += 1
    elsif line =~ /\n$/
      unix_newlines += 1
    else
      last_line_is_bare = true
    end
  end
  puts "#{filename}: windows #{windows_newlines} - #{unix_newlines} unix#{last_line_is_bare ? ' (no newline at EOF)' : ''}"
end

ARGV.each do |filename|
  begin
    open filename do |f|
      report_newlines filename, f
    end
  rescue => e
    puts "#{filename}: #{e}"
  end
end