Why is $ necessary to anchor the carriage return? You can't have a carriage return anywhere but the end of a line right?

It's not germaine to this particular example, but if you set $/ to something other than \n (or undef'ed it entirely), you might also be wanting to ignore those linebreaks that weren't against your arbitrary record seperator. So, in this case? The $ is optional. But there might be cases where it isn't. :-)
--
Jason Klueber
ookami@insightbb.com

/(bb)|^b{2}/
--Shakespeare