diff --git a/bin/dunecontrol b/bin/dunecontrol
index 673f0b401dbd1000e456f205f70598ae9e7520f6..704b4add887a4c70db2a9dffdb35716a2135ab6b 100755
--- a/bin/dunecontrol
+++ b/bin/dunecontrol
@@ -778,6 +778,8 @@ usage () {
     echo "                      (see dune-common/doc/example.opts)"
     echo "      --builddir=NAME make out-of-source builds in a subdir NAME."
     echo "                      This directory is created inside each module."
+    echo "                      If NAME is an absolute path, the build directory "
+    echo "                      is set to NAME/module-name for each module."
     echo "      --[COMMAND]-opts=opts   set options for COMMAND"
     echo "                     (this is mainly useful for the 'all' COMMAND)"
     echo "COMMANDS:"