Don't Forget -print (Unix Power Tools, 3rd Edition)

9.3. Don't Forget -print

"Why didn't find find my file?" I wondered sometimes. "I know it's there!"

More often than not, I'd forgotten to use -print. Without -print (or -ls, on versions of find that have it), find may not print any pathnames. For a long time, this quirk of find confused new users, so most modern versions of find will assume -print if you don't supply an action; some will give you an error message instead. If you don't get the output you expected from find, check to make sure that you specified the action you meant.

--JP and DJPH