ns_atshutdown - Queue a script to run when the server is terminating
This command queues a script to run when the server is terminating. The script and optional arg are concatenated together and added to the list of at-shutdown callbacks. The scripts are executed in the global scope in LIFO (last in, first out) order.
ns_atclose, ns_atexit, ns_atshutdown, ns_atsignal