diff --git a/lib.sh b/lib.sh
index ebe2d18..e9f1275 100644
--- a/lib.sh
+++ b/lib.sh
@@ -11,7 +11,7 @@ ask_yn() {
     local a
 
     read -rp "$* (Y/n) " a
-    [ -z "$a" ] || [[ "${a,,}" == y* ]]
+    [[ "${a,}" =~ ^$|^y ]]
 }
 
 declare -A ISO