leave
From NetBSD Wiki
The leave(1) command is a simple timer program which reminds you when you need to leave.
You can tell it to notify you 10 minutes from now:
$ leave +10
Or 10 hours from now:
$ leave +1000
Or leave 2 hours and 15 minutes from now:
$ leave +215
or
$ leave +0215
You can also ask it to notify you at a set time. Say you want to leave at one o clock (local time):
$ leave 1300
Or at a quarter past noon:
$ leave 1215
You can also invoke the command without arguments, then it will ask you
$ leave When do you have to leave?
after which you can type in a time.
When it is past time you leave, it will keep badgering you every single minute until you exit the controlling terminal.
