A couple of points that haven't been mentioned yet:
- Perl's input record separator $/ has a special "paragraph mode" when you set local $/=""; that will split the input on one or more blank lines.
- GrandFather mentioned the spaces in the regex. If you wanted to format your regex nicely and have whitespace ignored, you could use the /x modifier (perlre).
- Cristoforo's suggestion is nice and short, but has the disadvantage that it reads the entire file into memory before grepping it.