diff --git a/core/cli/dune b/core/cli/dune
index 0b7b93ae1..dd19581b4 100644
--- a/core/cli/dune
+++ b/core/cli/dune
@@ -1,7 +1,7 @@
 (library
  (name kappa_cli)
  (libraries
-  lwt
+  unix lwt
   (select
    superargTk.ml
    from