From: Robert Evans <robert.evans@...>
Date: 2007-04-05T04:39:04+09:00
Subject: Re: search a file and replace text

gsub! is destructive - it edits in-place and does not return a value.  
You could get a value back from gsub, but then you'd need to do  
something with that value.

The following worked, though I don't consider it elegant:

require 'fileutils'

File.open("/tmp/replaceable2.txt", 'w+') do | new_file |
     new_file.puts(File.open('/tmp/replaceable.txt', 'r') do |  
original_file |
                               original_file.read.gsub('30890', '44444')
                           end)
end
FileUtils.mv("/tmp/replaceable2.txt", "/tmp/replaceable.txt")

If you don't want the intermediate file, you could do something like  
this:

new_str = File.open('/tmp/replaceable.txt', 'r') { | f | f.read.gsub 
('30890', '44444') }
File.open('/tmp/replaceable.txt', w+) { |f| f.puts new_str }

Bob
http://www.junitfactory.com/



On Apr 3, 2007, at 10:00 AM, phil.swenson@gmail.com wrote:

> well I *THOUGHT* I knew how to do it, here's my first crack at it:
>
>         file_name = base_config_path + '/Caching/tangosol-
> coherence.xml'
>         File.open(file_name, File::RDWR).each{ |line|
>            if line.gsub!(/30890/, port.to_s)
>                 puts "tangosol port overridden with %d" % port
>                 break
>             end
>         }
>
>
> The gsub doesn't modify the line, guess it just modifies the string.
> How do I actually modify the file itself?
>
> btw, I did look at rexml but it looked like overkill for this.  I'll
> take another look though.
>
>