From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2012-04-17T16:32:39+09:00
Subject: Re: insert text after line "whatever"

On Mon, Apr 16, 2012 at 9:09 PM, fox foxmaster <lists@ruby-forum.com> wrote:
> Hi all,
>
> Does anyone have a solution on how to either see the problems with the
> above code or a solution on how to do it with reading line by line and
> inserting the text after a specific line?

Something like this should work:

File.open("destination.txt", "w") do |out|
  File.foreach("original.txt") do |line|
    out.puts line
    if line =~ /YOUR_REGEX/
      out.puts "THE NEW LINE"
    end
  end
end

Jesus.