#!/usr/bin/env python3
  
  import re, os, time, sys
  from time import time, sleep
  from os.path import join, getsize, getmtime
  
  if len(sys.argv) == 1:
      print("Argument Missing !")
      print("Usage:
      {0:s} /path/to/log/file".format(sys.argv[0]))
      sys.exit(1)
  
  startTime = time()
  mTimeStart = 0
  fileName = sys.argv[1]
  
  if not os.path.exists(fileName) or not os.path.isfile(fileName):
      print("This file '{0:s}' does not exist !".format(fileName))
      sys.exit(2)
  
  try:
      with open(fileName, 'r') as f:
          f.read(1)
  except Exception as e:
      print("This file '{0:s}' cannot be opened for reading !".format(fileName))
      sys.exit(3)
  
  folderLogs = os.path.dirname(fileName)
  
  copyLines = []
  
  try:
  
      while True:
          with open(fileName, 'r') as f:
              lines = f.readlines()
  
          show = False
  
          if len(copyLines) == 0:
              showLines = lines[-10:]
              show = True
  
          elif len(copyLines) != len(lines):
              showLines = lines[len(copyLines) - len(lines):]
              show = True
  
          if show:
              copyLines = lines.copy()
              for line in showLines:
                  print(line, end='')
  
          sleep(1)
  
  except KeyboardInterrupt as e:
      print("Program stopped by user !")
      sys.exit(0)
  
  except Exception as e:
      print("Unknown error during execution !")
      print(e)
      sys.exit(4)