This script tries to detect whether an HTTP Proxy works or not. It uses the HEAD command (high-level version of the lwp-request command) to connect to a given URL (http://www.google.com by default) via the given HTTP Proxy.
It takes 2 arguments; the first one is the IP Address or URL of the HTTP Proxy and the second one is its port number.
If you have a simpler or faster method, please let me know.