css_no_cache.rb

#! /usr/bin/env ruby

require "rubygems"
require "hpricot"

# File to alter and suffix to add
HEADER_FILE = "/path/to/your/file"
suffix      = "?time=" + Time.now.strftime('%Y%m%d%H%M%S')

# Use Hpricot to open and parse file as well as to find path
doc = open(HEADER_FILE) { |f| Hpricot(f) }
path = (doc/"#default-stylesheet").first['href']

# Grab the path, sans timestamp if necessary
base = path.split("?").first

# Alter path
(doc/"#default-stylesheet").first['href'] = base + suffix

# Write the fixed doc back out to the file
begin
  open(HEADER_FILE, 'w') do |f|
    f.write(doc)
    f.close
  end
  puts "The CSS path '#{base}' in '#{HEADER_FILE}' has been appended with '#{suffix}'"

rescue Exception => e
  puts "Error: #{e}"
end