old_contents: #!/usr/bin/env python
  import sys
  
  print("argv: %d" % len(sys.argv))
  
  # Object related test
  print(type(sys.argv))
  print(id(sys.argv))
  print(type(sys.argv) is list)
  
  if len(sys.argv) != 2:
      print("%s filename" % sys.argv[0])
      raise SystemExit(1)
  
  file = open(sys.argv[1], "w")
  
  line = []
  while True:
      line = sys.stdin.readline()
      if line == "quit\n":
          break
      file.write(line)
  file.close()
  
  print("\nok. start to dump %s:"  % sys.argv[1])
  for line in open(sys.argv[1]):
      print line.rstrip()
  
  file = open(sys.argv[1])
  lines = file.readlines()
  file.close()
  
  print(lines)
  
  fval = [float(line) for line in lines]
  
  print(fval)
  print("len: %d" % len(fval))
  
  for i in range(len(fval)):
      print i, " ", fval[i]
  
new_contents: #!/usr/bin/env python
  import sys
  
  print("argv: %d" % len(sys.argv))
  
  # Object related test
  # type and id are unique
  # ref: https://docs.python.org/2/reference/datamodel.html
  # mutable object: value can be changed
  # immutable object: value can NOT be changed after created
  #                   This means readonly
  #   ex: string, numbers, tuple
  
  print(type(sys.argv))
  print(id(sys.argv))
  print(type(sys.argv) is list)
  
  if len(sys.argv) != 2:
      print("%s filename" % sys.argv[0])
      raise SystemExit(1)
  
  file = open(sys.argv[1], "w")
  
  line = []
  while True:
      line = sys.stdin.readline()
      if line == "quit\n":
          break
      file.write(line)
  file.close()
  
  print("\nok. start to dump %s:"  % sys.argv[1])
  for line in open(sys.argv[1]):
      print line.rstrip()
  
  file = open(sys.argv[1])
  lines = file.readlines()
  file.close()
  
  print(lines)
  
  fval = [float(line) for line in lines]
  
  print(fval)
  print("len: %d" % len(fval))
  
  for i in range(len(fval)):
      print i, " ", fval[i]
  
subject: Add comment for object types