<a></a>
).以下代码应该可以工作。
require 'cgi'
description = "</p> <a href=\"http://url.com/trac/xxx/wiki/foo?action=diff&amp;version=28\">(diff)</a>"
CGI.unescapeHTML(description) # => </p> <a href="http://url.com/trac/xxx/wiki/foo?action=diff&version=28">(diff)</a>