diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index b80fc4b..163a6b8 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -1301,7 +1301,7 @@
 				die(_("submodule '%s' cannot add alternate: %s"),
 				    sas->submodule_name, err.buf);
 			case SUBMODULE_ALTERNATE_ERROR_INFO:
-				fprintf(stderr, _("submodule '%s' cannot add alternate: %s"),
+				fprintf_ln(stderr, _("submodule '%s' cannot add alternate: %s"),
 					sas->submodule_name, err.buf);
 			case SUBMODULE_ALTERNATE_ERROR_IGNORE:
 				; /* nothing */