from sys import argv
script, input_file = argv

def print_all(f):
  print f.read()

def rewind(f):
  f.seek(0) 
  #What seek() is and does: http://stackoverflow.com/questions/11696472/seek-function

def print_a_line(line_count, f):
  print line_count, f.readline()

current_file = open(input_file)

print "First let's print the whole file: \n"

print_all(current_file)

print "Now let's rewind, kind of like a tape"
rewind(current_file)

current_line = 0
for x in xrange(1,4):
  current_line += 1
  print_a_line(current_line, current_file)
  pass

