old_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  # using: Python 3.5.3
  
  import sys
  
  def main(args):
      # option is unimplemented
      if len(args) < 2:
          print('''
  brainfuck interpreter: ver 0.9.0
  usage:
  $ python bf.py [option] file
  
  sample:
  $ python bf.py example/hello.bf
  Brainfuck
      ''')
      elif len(args) > 3:
          print('''
      too many arguments.
      ''')
      else:
          token(args)
  
  # 1行ずつtokenに分割してリストに保存する
  def token(args):
      with open(args[1], 'r') as f:
          line = f.readline()
          list = []
          while line:
              for l in line:
                  list.append(l)
              line = f.readline()
          brainfuck(list)
  
  def brainfuck(list):
      x = []
      data = 0
      #listのインデックスをポインタとして使う
      ptr = 0
      i = 0
      for i in range(len(list)):
          if list[i] == '+':
              data += 1
          elif list[i] == '-':
              data -= 1
          elif list[i] == '.':
              x.append(data)
              print(chr(data), end="")
          elif list[i] == '>':
              x.append(0)
              ptr += 1
          elif list[i] == '<':
              ptr -= 1
          else:
              pass
  
      print("")
  
  
  if __name__ == '__main__':
      args = sys.argv
      main(args)
  
new_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  # using: Python 3.5.3
  
  import sys
  
  def main(args):
      # option is unimplemented
      if len(args) < 2:
          print('''
  brainfuck interpreter: ver 0.9.0
  usage:
      $ python bf.py [option] file
  
  sample:
      $ python bf.py example/hello.bf
      Brainfuck
      ''')
      elif len(args) > 3:
          print('''
      too many arguments.
      ''')
      else:
          token(args)
  
  # 1行ずつtokenに分割してリストに保存する
  def token(args):
      with open(args[1], 'r') as f:
          line = f.readline()
          list = []
          while line:
              for l in line:
                  list.append(l)
              line = f.readline()
          brainfuck(list)
  
  def brainfuck(list):
      x = []
      data = 0
      #listのインデックスをポインタとして使う
      ptr = 0
      i = 0
      for i in range(len(list)):
          if list[i] == '+':
              data += 1
          elif list[i] == '-':
              data -= 1
          elif list[i] == '.':
              x.append(data)
              print(chr(data), end="")
          elif list[i] == '>':
              x.append(0)
              ptr += 1
          elif list[i] == '<':
              ptr -= 1
          else:
              pass
  
      print("")
  
  
  if __name__ == '__main__':
      args = sys.argv
      main(args)
  
subject: fix usage