[attack]

Unless you want to delay it until birthdays or some other event that's weeks or months away.

[jrockway]

at lets you specify dates as day/month/year. All you have to do is make sure the computer is running at that time, which is easy if you do this on your mail server.

[attack]

That I know. I would never depend on a command line command to execute something months from now. Not on any system.