Apologize in advance, I am pretty new at php and ubuntu. I have 2 servers set up, one for development and one for staging. On the dev machine I can use the at command without a problem, but on staging I get a permissions error. The at.deny (and at.allow) files are identical, so it must be another permissions issue. Any clues? Thank you for your help. I see that on the staging server I can only use the at command as root. How can I fix this to be able to use the at command as www-data? Again... I checked the at.allow and at.deny files.. they are not the problem here. So what is?
I stumbled on this today. This answer implicitly suggested
chmod a+r /etc/at.allow, which helped. I am not sure whether this is the best/"official" way, but (a) it works for me, and (b) I don't see a lot of security risk in exposing the ids of users allowed to use
at (at least in my use-case).