diff --git a/boom/boom-config.in b/boom/boom-config.in
index d0efe01..5d6a6fe 100644
--- a/boom/boom-config.in
+++ b/boom/boom-config.in
@@ -18,6 +18,8 @@ base=`dirname "$base"`
 [ "$base" = "${base#/}" ] && base=`pwd`/$base
 [ . -ef "$base" ] && base=.
 
+[ "$1" ] || usage
+
 while [ "$1" ]; do
     case "$1" in
 	equ)