I'm using at
to schedule a task for a later time.
Will it survive a reboot, or should I re-assign all the tasks after reboot ?
It seems to be the case, the at
action will be preserved after reboot, as answered here.
Yes they are persistent across reboots (they're just files in a spool).
Files used by at
as detailed in the man page:
/var/spool/at
When you schedule an action, it will be stored in a file in /var/spool/at/<action_file>