diff --git a/plct.sh b/plct.sh
index 3887408..80ebc72 100755
--- a/plct.sh
+++ b/plct.sh
@@ -92,7 +92,7 @@ prepare_debian() {
 		exit 1
 	fi
 
-	if [ -n $disk ]; then
+	if [ -n "$disk" ]; then
 		while true; do
 			read -rp "everything is ok, type 'no' to cancel or 'yes' to preceed installation of debian $choice to $disk with $table table (DATA ON $disk WILL BE LOST): " proceeding
 			if [ "$proceeding" = "no" ]; then