I haven't heard of this before. It must have been introduced fairly recently; it isn't supported by bash 2.03 or any 1.x version.
it works for me with bash 2.05b - : send the line "unsubscribe linux-admin" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
