A systems administrator checked out the code from the repository, created a new branch, made changes to the code, and then updated the main branch. The systems administrator wants to ensure that the Terraform state files do not appear in the main branch. Which of following should the administrator use to meet this requirement?

Correct Answer:B
To prevent certain files from being tracked by Git, the administrator can use a .gitignore file (B) in the repository. The .gitignore file can specify patterns of files or directories that Git should ignore. This way, the Terraform state files will not appear in the main branch or any other branch. The other commands are not related to this requirement. References:
✑ [CompTIA Linux+ Study Guide], Chapter 10: Working with Git, Section: Ignoring Files with .gitignore
✑ [How to Use .gitignore File]

The development team wants to prevent a file from being modified by all users in a Linux system, including the root account. Which of the following commands can be used to accomplish this objective?

Correct Answer:C
The chattr command is used to change file attributes on Linux systems that support extended attributes, such as ext2, ext3, ext4, btrfs, xfs, and others. File attributes are flags that modify the behavior of files and directories.
To prevent a file from being modified by all users in a Linux system, including the root account, the development team can use the chattr +i /app/conf/file command. This command will set the immutable attribute (+i) on the file /app/conf/file, which means that the file cannot be deleted, renamed, linked, appended, or written to by any user or process. To remove the immutable attribute, the development team can use the chattr -i /app/conf/file command. The statement C is correct.
The statements A, B, and D are incorrect because they do not prevent the file from being modified by all users. The chmod /app/conf/file command does not work because it requires an argument to specify the permissions to change. The setenforce /app/conf/file command does not work because it is used to change the SELinux mode, not file attributes. The chmod 0000 /app/conf/file command will remove all permissions from the file, but it can still be modified by the root account. References: [How to Use chattr Command in Linux]

A systems administrator needs to verify whether the built container has the app.go file in its root directory. Which of the following can the administrator use to verify the root directory has this file?

Correct Answer:C
The docker exec <container_name> ls command can be used to verify whether the built container has the app.go file in its root directory. This command will run the ls command inside the specified container and list the files and directories in its root directory. If the app.go file is present, it will be displayed in the output. The docker image inspect command will display information about an image, not a container, and it will not list the files inside the image. The docker container inspect command will display information about a container, not its files. The docker ps <container_name> command is invalid, as ps does not accept a container name as an argument. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 16: Virtualization and Cloud Technologies, page 499.

Which of the following is the best tool for dynamic tuning of kernel parameters?

Correct Answer:A
The tuned application is the best tool for dynamic tuning of kernel parameters, as it monitors the system and optimizes the performance under different workloads. It provides a number of predefined profiles for typical use cases, such as power saving, low latency, high throughput, virtual machine performance, and so on. It also allows users to create, modify, and delete profiles, and to switch between them on the fly. The tuned application uses the sysctl command and the configuration files in the /etc/sysctl.d/ directory to adjust the kernel parameters at runtime.
References
✑ Chapter 2. Getting started with TuneD - Red Hat Customer Portal, paragraph 1
✑ Kernel tuning with sysctl - Linux.com, paragraph 1

An administrator needs to get network information from a group of statically assigned workstations before they are reconnected to the network. Which of the following should the administrator use to obtain this information?

Correct Answer:B
The ifcfg command is used to configure network interfaces on Linux systems. The -a option displays information about all network interfaces, including their IP addresses, netmasks, gateways, and other parameters. This command can help the administrator obtain the network information from the statically assigned workstations before they are reconnected to the network. References: [Linux Networking: ifcfg Command With Examples]

A cloud engineer needs to remove all dangling images and delete all the images that do not have an associated container. Which of the following commands will help to accomplish this task?

Correct Answer:A
The command docker images prune -a will help to remove all dangling images and delete all the images that do not have an associated container.
The docker command is a tool for managing Docker containers and images.
The images subcommand operates on images. The prune option removes unused images.
The -a option removes all images, not just dangling ones. A dangling image is an image that is not tagged and is not referenced by any container. This command will accomplish the task of cleaning up the unused images. The other options are incorrect because they either do not exist (docker push images -a or docker images rmi --all) or do not remove images (docker rmi -a images only removes images that match the name or ID of “images”). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 19: Managing Cloud and Virtualization Technologies, page 567.