I'd like to point out that very little of the trouble in the above had to do with
sed itself, per se, but with the
regular expressions used in the matching. I recommend that Holering take a little time to learn how to use at least the basics of regex more effectively.
Here are a few regular expressions tutorials:
http://mywiki.wooledge.org/RegularExpression
http://www.grymoire.com/Unix/Regular.html
http://www.regular-expressions.info/