gistfile1.rb

file = File.new("message_process.txt", "r")

id_counts = {}

while (line = file.gets)
  id = line.split[-2].split(":")[1].chop
  if id_counts.has_key? id 
    id_counts[id] += 1
  else
    id_counts[id] = 1
  end
end

id_counts.reject!{|k,v| v == 1 }

puts id_counts.keys.map(&:to_i).inspect

# [644, 364604, 387056, 364661, 387046, 364794, 702, 166535, 364675, 364609, 364621, 639, 364666, 915, 652, 389902, 438336, 364670, 654]