python 遍历文件目录并修改包含某字符串的文件名字

import sys
import os
def replace_filename(file_path,var1,var2):
for root,dirs,files in os.walk(file_path):
for file_name in files:
if var1 in file_name:
os.rename(os.path.join(root,file_name),os.path.join(root,file_name.replace(var1,var2)))
print('new file name is {0}'.format(file_name.replace(var1,var2)))

replace_filename(sys.argv[1],sys.argv[2],sys.argv[3])