clojure - difference between use and require

Question

Can anyone explain the difference between use and require, both when used directly and as :use and :require in the ns macro?

Answer 1

require loads libs (that aren't already loaded), use does the same plus it refers to their namespaces with clojure.core/refer (so you also get the possibility of using :exclude etc like with clojure.core/refer). Both are recommended for use in ns rather than directly.