As the time and date for each reminder arrives, you'll see a Growl notification.
Here's how to do it:
$ sudo launchctl load -F /System/Library/LaunchDaemons/com.apple.atrun.plist
Note: You only need to do this once to enable at() to work.
Try your first reminder:
$ at 11:19 today > growlnotify -m "eat a doughnut" -w -s > (ctl-d)
At 11:19 today, you'll see a Growl notification that says, "eat a doughnut"
It's also useful to Google around for tips on using at(). For example, the time specifications are very flexible. You can do, for example:
... and so on.
To see all your scheduled reminders, type: atq
To remove a reminder, type: atrm [job id]
See also: man at
Tue Oct 12 11:31:18 PDT 2010