my first python

#!/usr/bin/python
# -*- coding:utf8 -*-

import os
import re

def swap(path, a, b):
    print path
    file = open(path, "r").read()
    file = re.sub(a,b,file)
    #print file
    fw = open(path, 'wb')
    fw.write(file)
    #print fw.name()
    fw.close()

def getlist(path, src, dest):
    if( not os.path.isdir(path)):
        #print 'it is not dir'
        a,b = os.path.splitext(path)
        if b == ".as":
            swap(path, src, dest)
    else:
        path = path.replace("/", "\\")
        if path[-1] != "\\":
            path = path + "\\"
        a = os.listdir(path)
        for x in a :
            if os.path.isdir(path + x) and x != "CVS":
                getlist(path + x, src, dest)
            if os.path.isfile(path + x):
                a,b = os.path.splitext(path+x)
                if b == ".as":
                    swap(path+x, src, dest)

if __name__ == "__main__":
    import sys
    if len(sys.argv) == 1:
        print "nedd argv"
        exit()
    for i in sys.argv:
        if os.path.exists(i) and i != 'test01.py':
            print("please input: if a replaced with b  input a b")
            a=raw_input()
            print "your input is %s ." % a
            a,b = a.split()
            getlist(i, a,b)