at.allow, at.deny - determine who can submit jobs via at or batch
The /etc/at.allow and /etc/at.deny files
determine which user can submit commands for later execution
via at(1) or batch(1).
The format of the files is a list of usernames, one on each
line. Whitespace is not permitted.
The superuser may always use at.
If the file /etc/at.allow exists, only usernames
mentioned in it are allowed to use at.
If /etc/at.allow does not exist, /etc/at.deny
at(1), atrun(1)?, cron(8),