Recursively find and replace string in text files

os.walk is great. However, it looks like you need to filer file types (which I would suggest if you are going to walk some directory). To do this, you should add import fnmatch.

import os, fnmatch
def findReplace(directory, find, replace, filePattern):
    for path, dirs, files in os.walk(os.path.abspath(directory)):
        for filename in fnmatch.filter(files, filePattern):
            filepath = os.path.join(path, filename)
            with open(filepath) as f:
                s = f.read()
            s = s.replace(find, replace)
            with open(filepath, "w") as f:
                f.write(s)

This allows you to do something like:

findReplace("some_dir", "find this", "replace with this", "*.txt")