try the =~ operation syntax string buzzword (was in original post: thingy)
$blah=~s/\W+/$blah2/

just had to be the first to comment, but I missed it anyway. Didn't want to be left behind when swiftone started editing his!
This doesn't prevent you from doing

my ($something) = my ($something2) = $blah =~s/\W+/$blah2/
[download]

Beat that, swiftone! :)

-Nimster