Get users From Passwd file

#!/usr/bin/python
import os

def Color() : # Thank:r0kin
  if os.name == 'nt':
    os.system('cls') # Windows
    os.system('color a')
  else:
    os.system('clear') # Linux
Color()
print '''
###################################
# c0ded by SoUiLaHxXx_Dz ^_^
#  Get Users From Passwd File
###################################
'''

a = raw_input("Enter passwd file : ")

pf = open("file.txt" , "r")

for i in pf.readlines():
  b = i.find(":")
  print b[0]

pf.close()