core.clj

(reduce (fn [mentioned-files file]
          (if (some #{file} mentioned-files)
            mentioned-files
            (let [duplicates (duplicates-of-file file files (:precision options))]
              (when (seq duplicates)
                (printf "%s\n" file)
                (doseq [d duplicates]
                  (printf "%s\n" d))
                (printf "\n"))
              (concat mentioned-files duplicates))))
        (), files)