osx_mem_stats.rb

`sudo purge`

memory_by_process = Hash.new(0)
processes = `ps aux`

m_bytes = processes.split("\n").reduce(0) { |memo, prc|
  fields    = prc.split(/\s+/)

  mem_bytes = fields[5].to_i
  prc_name  = fields[10...fields.length].join(' ')
  prc_name = 'Chrome.app' if prc_name.include? 'Chrome'

  memory_by_process[prc_name] += mem_bytes

  memo + mem_bytes
}

mega_bytes = (m_bytes / 1024.0).round(2)
total_memory = `sysctl hw.memsize`.match(/\d+/)[0].to_i # hw.memsize: 17179869184
total_memory_in_megabytes = total_memory / 1024 / 1024
one_percent_from_total_memory = (total_memory_in_megabytes / 100.0)
used_percent = (mega_bytes / one_percent_from_total_memory).round(2)
puts "Total: #{mega_bytes}MBs of #{total_memory_in_megabytes}MBs of RAM is used by processes (#{used_percent}% is used)"

puts "TOP-20:"
top_ten_bytes_sum = 0
memory_by_process.sort_by { |k, value| value }.reverse[0...20].each { |mem|
  prc_name = mem[0][0...96]
  prc_name += '...' if mem[0].length > 96
  m_bytes = mem[1] / 1024.0
  mega_bytes = m_bytes.round(2)
  percent = (mega_bytes / one_percent_from_total_memory).round(2)
  puts "#{mega_bytes} #{percent}%\t#{prc_name}"
  top_ten_bytes_sum += mem[1]
}
mega_bytes = sprintf("%.2f", top_ten_bytes_sum / 1024.0)
puts "TOP-20 summary uses #{mega_bytes} Mb of memory"