Periodic execution of a program

[Guy Harris]

>On our system, at least, there is a command called 'crontab' which lets
>ordinary users submit crontabs to be run by cron.

I infer from the fact that he said "BSD 4.3" that he's running inside
the BSD universe on his Pyramid, so I don't think the "crontab" command
is accessible by default.  "att crontab" might work, as S5R2 and later
do have that "crontab" mechanism.

>at -r <jobnum> will remove a job from the queue, and at -l will list
>the current jobs.

"atrm" and "atq" respectively would, I assume, be the versions in the
BSD universe, those being the BSD flavor of those functions.