#!/bin/bash

echo -n Your age:
read AGE

#Problem with output as () cause to execute command in subshell.
#[ $AGE -lt 20 ] && (echo You are not allowed to see secret; exit 1) || echo Welcome

#command execute it same shell
[ $AGE -lt 20 ] && { echo You are not allowed to see secret; exit 1;} || echo Welcome

echo Secret is that there is no secret