fibonacci.py

#!/usr/bin/python3

import sys

def print_fibonacci(howMany):
  a, b = 0, 1
  while a < howMany:
    print(a)
    a, b = b, a + b

def main():
  limit = 0
  if (len(sys.argv) != 2):
    limit = 10
  else:
    try:
      limit = int(sys.argv[1])
      print_fibonacci(int(limit))
    except ValueError as err:
      print('An integer is required: {0}'.format(err))

if __name__ == '__main__':
  main()