diff --git a/bin/vmail-aliases-del.sh b/bin/vmail-aliases-del.sh
index b83245f..c506282 100755
--- a/bin/vmail-aliases-del.sh
+++ b/bin/vmail-aliases-del.sh
@@ -51,6 +51,9 @@ while getopts "h" opt; do
     \? )
       echo "Invalid option: $OPTARG" 1>&2
       exit;;
+    : )
+      echo "Invalid option: $OPTARG requires an argument" 1>&2
+      exit;;
   esac
 done