https://code.google.com/archive/p/css-redundancy-checker/
wget https://storage.googleapis.com/google-code-archive-source/v2/code.google.com/css-redundancy-checker/source-archive.zip unzip source-archive.zip gem install hpricot ruby css-redundancy-checker.rb [cssfile] [directory of html files OR .txt file listing urls to use]
# vim url.txt http://www.netkiller.cn/zh-cn/ http://www.netkiller.cn/index.html http://www.netkiller.cn/zh-tw/index.html ruby css-redundancy-checker.rb your.css url.txt