diff --git a/src/maketools/update-config-txt.sh b/src/maketools/update-config-txt.sh
index 7a604f6c9fd35c1963b1ddec97e1e44eebb21005..6535f75aea20862a97d26c2d0b682d7c8ec6c493 100755
--- a/src/maketools/update-config-txt.sh
+++ b/src/maketools/update-config-txt.sh
@@ -101,6 +101,8 @@ echo "# version strings"
 echo "# syntax: version short/long/git number"
 echo "$version"
 echo
+echo "# command to lauch mpi processes"
+echo "# syntax: mpiexec command"
 echo "mpiexec $mpiexec"
 echo
 echo "# list of 'has' options"