Clearing DNS cache – regex part 2

Trust me. We’re still dealing with regexes – just in a roundabout (and vaguely practical) way. This is a pretty comprehensive listing of how to go about flushing DNS caches while using regexes to show where similar methods deviate.
Why do we want to clear DNS caches exactly?
There are a number of reasons to clear DNS [...]

www FTL — oh and a small SEO tip

Have you previously realised that www is redundant? If so, I’m preaching to the converted and you can run along back to whatever you were busy with. Otherwise, stand to attention, soldier!
begin rantish text:
When I’m browsing the web, I’d much less prefer to type “www.xkcd.com” than “xkcd.com”. Reason being that if *every* site [...]