I have never actually used "at", but I remembered there was a fix a broken "at" posted back in VL6 SOHO Beta 4 days, I don't know if this is at all relevant for your issue with VL6 Std though.
The fix was to do the following as root:
chmod 660 /var/spool/atjobs/.SEQ
chown daemon.daemon /var/spool/atjobs/.SEQ
chmod 640 /etc/at.deny
chown root.daemon /etc/at.deny
Nope above changed nothing. The moment I start 'at' it eats up CPU usage.
I like 'at'. It is fast. Coming from the dentist in a terminal type:
at now +6 month
enter commands like a sound, followed by xmessage for a message
then finish with
and exactly in 6 months it will remind you to go to the dentist, if that was your message.
If have tried various schedulers and never was able to figure them out
being gui challenged.