#!/usr/bin/python import re, sys, uuid guid_re = re.compile("[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{12}") guid_dt = {} def mk_guid(m): guid = m.group(0).upper() if guid not in guid_dt: guid_dt[guid] = str(uuid.uuid4()).upper() return guid_dt[guid] with open(sys.argv[1]) as file: text = file.read() text = guid_re.sub(mk_guid, text) sys.stdout.write(text)