"at" command and mail

[Robert Bonomi]

> From owner-freebsd-questions at freebsd.org  Sat Sep  3 11:39:54 2011
> Date: Sat, 03 Sep 2011 10:39:44 -0600
> To: questions at freebsd.org
> From: Brett Glass <brett at lariat.net>
> Cc: 
> Subject: "at" command and mail
>
> I'm setting up a FreeBSD appliance that won't be running a mail 
> daemon. I'd like the at(8) command to be there for scheduling of 
> commands, but do not see any way to prevent it from trying to send 
> mail after it executes a command. (There's not even a command line 
> option that says "do not mail," or at least I can't find one.) Am I 
> missing something, or does at(8) always expect to be able to send 
> mail? If so, would it be worth implementing an atrun.conf 
> configuration file that makes it optional and possibly sets other 
> defaults for at(8)?

Is 'atrun' actually sending the mails or is 'cron' doing it?  'atrun' is
invoked by 'cron', from a specification in the system crontab file.

Cron emails *whenever* a cron-scheduled job produces stdout or stderr
output.

Thus, by modifying the atrun line in crontab, to redirect both stdout
and stderr to /dev/null, you should prvent any 'mailing'.

You could, in theory, have the crontab line _append_ output to a filename
based on a timestamp, however, that intermixes output from all users.