findandreplace.py

import os
import sys


dirpath = sys.argv[1]
oldtext = sys.argv[2]
newtext = sys.argv[3]

for root, subdirs, files in os.walk(dirpath):
	for filename in files:
		filepath = os.path.join(root, filename)

		print(filepath)

		with open(filepath, 'r') as fp:
		  data = fp.read()

		data = data.replace(oldtext, newtext)

		with open(filepath, 'w') as fp:
		  fp.write(data)