A new HTTPS web service is being deployed on a server. Which of the following commands should the Linux administrator use to ensure traffic is able to flow through the system firewall to the new service?

An administrator needs to create a shared directory in which all users are able, write, and execute its content but none of the regular users are able to delete any content.
Which of the following permissions should be applied to this shared directory?

A Linux amdinisrator is adding a user's local Linux account to the accounting group. The user is also a member of the finance group. Which of the following is the BEST way to add the user to the accounting group while still maintaining the user's existing group members ships?

An administrator is reviewing suspicious activity on a server and needs to determine which users logged into the system within the past 24 hours. Which of the following commands should the administrator run to determine this?

A new IO card has been added to the security server to log the opening and closing of the main entrance. A switch is attached, so the interface card returns a 1 when the door is opened and a 0 when the door is closed.
Which of the following describes the Linux device to which this switch is attached?