Scheduling tasks with at

You can also schedule tasks for midnight, noon and teatime (4 PM) by directly using these words along with at command:

at midnight
at noon
at teatime

Along with time in HH:MM format, you can specify the date in MMDDYY format:

at 23:30 123123

You can also schedule tasks to take place after a particular amount of time starting from now:

at now + 1 minute
at now + 1 hour
at now + 1 week
at now + 1 year

AM/PM:

at 9:00 AM
at 9:00 PM

Other useful commands:
atq: Lists all the scheduled tasks that are pending.
atrm: Removes scheduled tasks