import os
import re
from os.path import walk
for root, dirs, files in os.walk("/home/noa/Desktop/codes"):
        for name in dirs:
                re.search("dbname=noa user=noa", "dbname=masi user=masi")
                   // I am trying to replace here a given match in a file

#!/usr/bin/python

import os
import re
import sys

# list of extensions to replace
replace_extensions = []
# example: uncomment next line to only replace *.c, *.h, and/or *.txt
# replace_extensions = [".c", ".h", ".txt"]

def try_to_replace(fname):
    if replace_extensions:
        return fname.lower().endswith(replace_extensions)
    return True


def file_replace(fname, pat, s_after):
    # first, see if the pattern is even in the file.
    with open(fname) as f:
        if not any(re.search(pat, line) for line in f):
            return # pattern does not occur in file so we are done.

    # pattern is in the file, so perform replace operation.
    with open(fname) as f:
        out_fname = fname + ".tmp"
        out = open(out_fname, "w")
        for line in f:
            out.write(re.sub(pat, s_after, line))
        out.close()
        os.rename(out_fname, fname)


def mass_replace(dir_name, s_before, s_after):
    pat = re.compile(s_before)
    for dirpath, dirnames, filenames in os.walk(dir_name):
        for fname in filenames:
            if try_to_replace(fname):
                fullname = os.path.join(dirpath, fname)
                file_replace(fullname, pat, s_after)

if len(sys.argv) != 4:
    u = "Usage: mass_replace <dir_name> <string_before> <string_after>n"
    sys.stderr.write(u)
    sys.exit(1)

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

import os

def recursive_replace( root, pattern, replace )
    for dir, subdirs, names in os.walk( root ):
        for name in names:
            path = os.path.join( dir, name )
            text = open( path ).read()
            if pattern in text:
                open( path, 'w' ).write( text.replace( pattern, replace ) )

find /home/noa/Desktop/codes -type f -print0 |
xargs -0 sed --in-place "s/dbname=noa user=noa/dbname=masi user=masi"

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)

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