An administrator notices the HISTSIZEvariable is 50, using the commands below:
HISTSIZE=50
export HISTSIZE
The administrator rechecks the HISTSIZEvalue using echo HISTSIZEbut gets no value. Which of the following commands should the administrator use to retrieve its value?

A systems administrator has set up third-party log aggregation agents across several cloud instances. The systems administrator wants to create a dashboard of failed SSH attempts and the usernames used.
Which of the following files should be watched by the agents?

A junior administrator needs to unload an older video kernel module.
Which of the following commands would BEST accomplish this task?

Which of the following commands will let a Linux user know the PCI devices that are installed in the system?

A Linux administrator is setting up a testing environment and needs to connect to a separate testing server using the production server name. The administrator needs to override the hostname that the DNS is returning in order to use the test environment. Which of the following commands should be run on each of the testing systems to BEST meet this goal?