Exam 102-500 Topic 7 Question 134 Discussion

The /etc/at.deny file is a file that contains a list of users who are not allowed to use the at command to schedule jobs. If the file exists, any user who is not in the /etc/at.allow file and is in the /etc/at.deny file will be denied access to the at command. To prevent a specific user from scheduling tasks with at, the administrator can simply add the user's name to the /etc/at.deny file. For example, to prevent the user bob from using the at command, the administrator can use the following command:
echo "bob" | sudo tee -a /etc/at.deny
The other options are not correct. The /etc/at.allow file is a file that contains a list of users who are allowed to use the at command. Adding a user to this file will not prevent them from scheduling tasks with at. The
/etc/atd.conf file is a configuration file for the at daemon, which does not have a [deny] section. Adding a user to this file will not affect their access to the at command. The nojobs group is not a predefined group in Linux, and adding a user to this groupwill not prevent them from scheduling tasks with at. The atd command does not have a --deny option, and running this command will not prevent a user from scheduling tasks with at.
References:
* at Command in Linux with Examples - GeeksforGeeks
* How to Use the Linux at Command {9 Examples} - phoenixNAP
* at(1) - Linux man page