need some regular expression help

[Roy Smith]

"Diez B. Roggisch" <deets at web.de> wrote:
> Certainly true, and it always gives me a hard time because I don't know
> to which extend a regular expression nowadays might do the job because
> of these extensions. It was so much easier back in the old times....

What old times?  I've been working with regex for mumble years and there's 
always been the problem that every implementation supports a slightly 
different syntax.  Even back in the "good old days", grep, awk, sed, and ed 
all had slightly different flavors.