dir = ENV.fetch("PROCIO_DIR", "/proc")
result = {} of String => Array(UInt64)
time = Time.local.to_s("%s%9N")

Dir.entries(dir).each do |entry|
  entry =~ /^\d+$/ || next 

  comm = File.read("#{dir}/#{entry}/comm").chomp
  result[comm] ||= [0.to_u64, 0.to_u64]

  File.read_lines("#{dir}/#{entry}/io").each do |line|
    if line.starts_with?("read_bytes: ")
      result[comm][0] += line.split(" ").last.to_u64
    elsif line.starts_with?("write_bytes: ")
      result[comm][1] += line.split(" ").last.to_u64
    end
  end
end

result.each do |comm, (r, w)|
  if r + w > 0
    puts %(procio,comm="#{comm}" read_bytes=#{r},write_bytes=#{w} #{time})
  end
end