Sass + Compass compila dois arquivos diferentes para o ambiente de desenvolvimento e produção

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

Estrutura de arquivo

<project folder>/    
CSS/

SCSS/

style.scss

style.css

style.min.css

IMG/

JS/

config.rb

watch.bat