gistfile1.txt

              getSize = (filename, callback) ->
                fs.stat filename, (err, stat) ->
                  if err
                    if err.errno == process.ENOENT
                      return callback null, 0
                    return callback err
                  callback null, stat.size

              getTotal = (filename, num, callback) ->
                finish = ->
                  callback total

                for i in [0...num]
                  Common.getSize "#{filename}.#{i}", (err, size) ->
                    throw err if err
                    total += size
                    finish() if i is num - 1
                    
              getTotal filename, 3, (total) ->
                console.log total