From: Thomas Pierce <ruby@...>
Date: 2008-02-18T13:00:29+09:00
Subject: Help with Writing Replacement Text to Files

Hello!

I'm new to ruby and been reading this very active list for about a  
couple of week.

I have a project at work where I need to write a simple script to  
scrub IP addresses from configuration files for classified networks we  
work in sometimes. The goal is to cleanse configuration files  
sometimes required for support of any specific network addressing  
information. Here is what I've come up with so far. While this works  
in IRB on the file object I create, I cannot figure out how to write  
the changes back in place to the actual file itself back on the regex  
I'm using:

  config_file = File.open("config.txt")
         config_txt = config_file.read
         config_txt.gsub!(/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/,  
"000.000.000.000")

I do understand that the default action here is read-only. How to do I  
parse with the regex on the current file and replace matching strings  
without either appending to the file, overwriting the file, or  
creating a new file?

Thanks!

~Thomas