diff --git a/bora.sh b/bora.sh
index 6d32d67..44612e2 100644
--- a/bora.sh
+++ b/bora.sh
@@ -1,5 +1,11 @@
 #!/usr/bin/sh
 
+if [ $# = 0 ]
+then
+	echo "Usage: $0 <URL> <output>"
+	exit
+fi
+
 webcams=webcams.webm
 deskshare=deskshare.webm
 if [ "$1" != "-" ]