diff --git a/installers/install_osm.sh b/installers/install_osm.sh
index 50c1111..fcdcdf9 100755
--- a/installers/install_osm.sh
+++ b/installers/install_osm.sh
@@ -90,7 +90,7 @@
   return 1
 }
 
-while getopts "hr:R:u:t:" o; do
+while getopts ":hr:R:u:t:-:" o; do
     case "${o}" in
         h)
             usage && exit 0
@@ -107,6 +107,10 @@
         t)
             OSM_DOCKER_TAG="${OPTARG}"
             ;;
+        -)
+            [ "${OPTARG}" == "help" ] && usage && exit 0
+            continue
+	    ;;
         *)
             ;;
     esac