diff --git a/check_snmp_synology b/check_snmp_synology
index 2f9c8a2885e3fb8cffbb2b1fbeba1fbc803ff9d0..d138bd1017400d2e85f494b659ed3d49bc0f65d1 100755
--- a/check_snmp_synology
+++ b/check_snmp_synology
@@ -195,6 +195,8 @@ _add_status(){
 # MAIN
 # ----------------------------------------------------------------------
 
+test $# -eq 0 && usage
+
 while getopts a:h:f:vsdut OPTNAME; do
     case "$OPTNAME" in
         a)