Reorder Weka parsed CSV files

reorder_csv.rb

file_p = File.open(ARGV[0])
lines = file_p.readlines
file_p.close

lines.each do |line|
  
  match_data = line.strip.match(/".+(n[0-9]+)_(.+)[.]log",(.+)/)
  if match_data != nil
    puts "#{match_data[2]}_#{match_data[1]},#{match_data[3]}"
  else
    puts line
  end
end