Discarding output
Unix shell nerds discard unwanted output by redirecting it to /dev/null. The equivalent in Common Lisp is the empty broadcast stream returned by a call to make-broadcast-stream with no arguments.
For example, if you have some code that normally prints to *standard-output*, but you want that output discarded, you can do something like this:
(let ((*standard-output* (make-broadcast-stream))) (app:noisy-code))