from sys import argvscript,input_file = argvdef print_all(f):    print f.read()def rewind(f):    f.seek(0)def print_a_line(line_count,f):    print line_count,f.readline()current_file = open(input_file,'r')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)print "Let's print three line:"current_line = 1print_a_line(current_line,current_file)current_line = current_line+1print_a_line(current_line,current_file)current_line = current_line+1print_a_line(current_line,current_file)