config.rb

// Syntax
preferred_syntax = :scss

// Paths
http_path = "/"
images_dir = "/img"
javascripts_dir = "/js"
sass_dir = "/css/scss/"
css_dir = "/css/"

if environment == :development
 line_comments = true
 output_style = :nested
 sass_options = {:debug_info => true}
end

if environment == :production
 line_comments = false
 output_style = :compressed
 sass_options = {:debug_info => false}

 require 'fileutils'
 on_stylesheet_saved do |file|
 if File.exists?(file)
 filename = File.basename(file, File.extname(file))
 File.rename(file, "css" + "/" + filename + ".min" + File.extname(file))
 end
 end
end 

watch.bat

START compass watch -c config.rb -e development
START compass watch -c config.rb -e production
EXIT

File structure

<project folder>/ 
 CSS/
 SCSS/
 style.scss
 style.css
 style.min.css
 IMG/
 JS/
 config.rb
 watch.bat