1  import sys
 2  
 3  if len(sys.argv) < 2:
 4      sys.exit("Too few command-line arguments")
 5  elif len(sys.argv) > 2:
 6      sys.exit("Too many command-line arguments")
 7  else:
 8      filename = sys.argv[1]
 9  
10  if not filename.endswith(".py"):
11      sys.exit("Not a Python file")
12  
13  try:
14      file = open(filename, "r")
15  except FileNotFoundError:
16      sys.exit("File does not exist")
17  
18  count = 0
19  
20  for line in file:
21      if line.strip().startswith("#"):
22          continue
23      elif line.strip() == "":
24          continue
25      else:
26          count += 1
27  
28  print(count)