string replace in python

replace.py

#! /usr/bin/env python

import sys, re

def conf_file(path):
    f = open(path, 'r')
    res = []
    for line in f.readlines():
        line = line.replace('vprintf', 'sd_printf')
        line = line.replace('eprintf', 'sd_eprintf')
        line = line.replace('dprintf', 'sd_dprintf')
        res.append(line)
    f.close()

    f = open(path, 'w')
    for line in res:
        f.write(line)

for path in sys.stdin.readlines():
    conf_file(path.rstrip())