OK, your bringing out the chainsaw here.I know perl is great, but sometimes its overkill. This at least works with gnu chmod and probably most other UNIX OS:

chmod -R go=rX,u=rwX <dirname> <dirname>
[download]

The capital X turns on execution if its a directory, or if it has one or more execution bits allready set. The -R means that it changes permission recursively on all the directories its given.

GoldClaw