A.By adding the specific user to the /etc/at.deny file.

B.By adding the specific user to the nojobs group.

C.By executing the atd --deny [user] command.

D.By adding the specific user to the [deny] section in the /etc/atd.conf file.

E.By adding the specific user to the /etc/at.allow file.

A.until

B.loop

C.for

D.while

A.The new configuration becomes effective after restarting the respective service.

B.The new configuration becomes effective immediately for all new connections.

C.The new configuration becomes effective at the next system reboot.

D.The new configuration becomes effective after restarting the tcpd service.

E.The new configuration becomes effective when the last established connection to the service is closed.

A.env -a

B.env

C.echo $ENV

D.set

A.The sendmail command prints the MTA's queue history of which mails have been sent successfully.

B.When using systemd, sendmail is an alias to relayctl.

C.It is only available when the sendmail MTA is installed.

D.With any MTA, the sendmail command must be run periodically by the cron daemon.

E.All common MTAs, including Postfix and Exim, provide a sendmail command.