old_contents: #!/usr/bin/env python
  #encoding: utf8
  import sys, rospy
  from piavatar_ros.msg import LightSensorValues
  
  def get_freq():
      f = rospy.get_param('lightsensors_freq',10)
      try:
          if f <= 0.0:
              raise Exception()
      except:
          rospy.logger("value error: lightsensors_freq")
          sys.exit(1)
  
      return f
          
  if __name__ == '__main__':
      devfile = '/dev/rtlightsensor0'
      rospy.init_node('lightsensors')
      pub = rospy.Publisher('lightsensors', LightSensorValues, queue_size=1)
  
      freq = get_freq()
      rate = rospy.Rate(freq)
      while not rospy.is_shutdown():
          try:
              with open(devfile, 'r') as f:
                  data = f.readlien().split()
                  data = [ int(e) for e in data ]
                  d = LightSensorValues()
                  d.right_forward = data[0]
                  d.right_side = data[1]
                  d.left_side  = data[2]
                  d.left_forward = data[3]
                  d.sum_all = sum(data)
                  d.sum_forward = data[0] + data[3]
                  pub.publish(d)
          except IOError:
              rospy.logerr("cannot write to " + devfile)
  
          f = get_freq()
          if f != freq:
              freq = f
              rate = rospy.Rate(freq)
  
          rate.sleep()
   
  
new_contents: #!/usr/bin/env python
  #encoding: utf8
  import sys, rospy
  from piavatar_ros.msg import LightSensorValues
  
  def get_freq():
      f = rospy.get_param('lightsensors_freq',10)
      try:
          if f <= 0.0:
              raise Exception()
      except:
          rospy.logger("value error: lightsensors_freq")
          sys.exit(1)
  
      return f
          
  if __name__ == '__main__':
      devfile = '/dev/rtlightsensor0'
      rospy.init_node('lightsensors')
      pub = rospy.Publisher('lightsensors', LightSensorValues, queue_size=1)
  
      freq = get_freq()
      rate = rospy.Rate(freq)
      while not rospy.is_shutdown():
          try:
              with open(devfile, 'r') as f:
                  data = f.readline().split()
                  data = [ int(e) for e in data ]
                  d = LightSensorValues()
                  d.right_forward = data[0]
                  d.right_side = data[1]
                  d.left_side  = data[2]
                  d.left_forward = data[3]
                  d.sum_all = sum(data)
                  d.sum_forward = data[0] + data[3]
                  pub.publish(d)
          except IOError:
              rospy.logerr("cannot write to " + devfile)
  
          f = get_freq()
          if f != freq:
              freq = f
              rate = rospy.Rate(freq)
  
          rate.sleep()
   
  
subject: Revise a file