diff --git a/guix/scripts/build.scm b/guix/scripts/build.scm
index 1d766c0b01..a357cf8aa4 100644
--- a/guix/scripts/build.scm
+++ b/guix/scripts/build.scm
@@ -538,14 +538,7 @@ arguments with packages that use the specified source."
                          roots))
               ((not (assoc-ref opts 'dry-run?))
                (and (build-derivations store drv)
-                    (for-each (lambda (d)
-                                (format #t "~{~a~%~}"
-                                        (map (match-lambda
-                                              ((out-name . out)
-                                               (derivation->output-path
-                                                d out-name)))
-                                             (derivation-outputs d))))
-                              drv)
+                    (for-each show-derivation-outputs drv)
                     (for-each (cut register-root store <> <>)
                               (map (lambda (drv)
                                      (map cdr
diff --git a/guix/ui.scm b/guix/ui.scm
index e028e40f6e..4a3630f242 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -62,6 +62,7 @@
             show-bug-report-information
             string->number*
             size->number
+            show-derivation-outputs
             show-what-to-build
             show-what-to-build*
             show-manifest-transaction
@@ -502,6 +503,14 @@ error."
      (leave (_ "expression ~s does not evaluate to a package~%")
             str))))
 
+(define (show-derivation-outputs derivation)
+  "Show the output file names of DERIVATION."
+  (format #t "~{~a~%~}"
+          (map (match-lambda
+                 ((out-name . out)
+                  (derivation->output-path derivation out-name)))
+               (derivation-outputs derivation))))
+
 (define* (show-what-to-build store drv
                              #:key dry-run? (use-substitutes? #t))
   "Show what will or would (depending on DRY-RUN?) be built in realizing the