if you are talking about replacing in strings, most text editors have 
search/replace functions to.
want to do it in ruby¡© take a look at String.gsub

--------------------------------------------------
From: "Adam Abc" <racula / live.com>
Sent: Sunday, February 20, 2011 10:52 AM
Newsgroups: comp.lang.ruby
To: "ruby-talk ML" <ruby-talk / ruby-lang.org>
Subject: Possible combination trick

> Let's say I have this:
>
> to you the dog
> to that the dog
> was to the dog
> and you the dog
> you and the dog
> and that the dog
> and he the dog
> he and the dog
> and was the dog
>
> and I want this
>
> to you and this
> to that and this
> was to and this
> and you and this
> you and and this
> and that and this
> and he and this
> he and and this
> and was and this
>
> How do you change every the dog to and this? Then have it sent to a .rb
> file.
>
> -- 
> Posted via http://www.ruby-forum.com/.
>
>