Properly added case for an absent subcommand

zfs/zfs-media-drive.sh

@@ -64,6 +64,10 @@ print_menu () {
 	echo "Placeholder content"
 }
 
+if [ -z "$1" ]; then
+	exit 1
+fi
+
 if ! [ -z "$1" ] && [ "$1" == "init" ]; then
 	while getopts "d:p:k:f:c:v:" opt; do
 		case $opt in