CompTIA XK0-006 Practice Test Questions Answers

Container management and image handling are part of modern Linux automation practices covered in CompTIA Linux+ V8. Docker images are stored in container registries such as Docker Hub, and administrators commonly need to download images to deploy containers.

The correct command for downloading an image from a Docker repository is docker image pull. This command retrieves the specified image from a configured container registry and stores it locally. When no tag is specified, Docker automatically pulls the latest available version of the image. Therefore, docker image pull debian downloads the most recent Debian image from Docker Hub.

The other options are incorrect. docker image init is not a valid Docker command and does not exist in Docker’s CLI. docker image import is used to create a Docker image from a tarball file, not to download an image from a repository. docker image save exports an existing local image into a tar archive and does not retrieve images from a remote registry.

Linux+ V8 documentation emphasizes understanding container image lifecycles, including pulling, tagging, and running images. Pulling images is a foundational step before container execution and automation workflows.

Therefore, the correct answer is B. docker image pull debian.

Disk forensics and malware analysis fall under the Security domain in the CompTIA Linux+ V8 objectives. When analyzing a compromised disk, it is critical to preserve the data exactly as it exists, including unused space, deleted files, and hidden metadata. This requires a block-level copy, not a file-level copy.

The dd command is the correct tool for this task. It operates at a low level, copying raw data from an input device (if=/dev/sdc) directly to an output file (of=/tmp/image) without interpreting filesystem structures. This ensures an exact, bit-for-bit replica of the disk, which is essential for forensic integrity and malware analysis. The bs=8192 option improves performance by specifying a larger block size during copying.

The other options are incorrect. cp -rp copies files and directories but does not capture free space, deleted data, or disk metadata. cpio and tar are archive utilities that operate at the filesystem level and cannot produce a true disk image. These tools also require the filesystem to be mounted and readable, which is not appropriate for forensic preservation.

Linux+ V8 documentation highlights dd as the preferred utility for disk imaging, backups, and forensic investigations. Administrators are also advised to perform such operations on unmounted disks to avoid altering evidence.

Therefore, the correct and best command for creating an exact block-level disk copy is D. dd if=/dev/sdc of=/tmp/image bs=8192.

This scenario involves shared directory collaboration, which is a common system management task covered in the CompTIA Linux+ V8 objectives. The key issue is that users can create files in the shared directory, but other users in the same group cannot modify those files. This behavior is directly related to group ownership inheritance.

By default, when a user creates a file or directory, it is owned by the user and assigned the user’s primary group, not necessarily the group of the parent directory. As shown in the output, files inside /share are owned by different groups (student, student2, student3), which prevents other group members from modifying them, even though the parent directory is group-writable.

The correct solution is to set the setgid (set group ID) bit on the shared directory, making option D correct. When the setgid bit is applied to a directory, all newly created files and subdirectories inherit the group ownership of the parent directory, rather than the creator’s primary group. This ensures consistent group ownership and allows all members of the shared group to collaborate effectively.

The other options are incorrect or poor practice. Option A (setuid) is intended for executables, not directories. Option B requires constant manual intervention and does not scale. Option C weakens security by granting write access to all users, violating the principle of least privilege.

Linux+ V8 documentation explicitly recommends using the setgid bit on shared directories to manage collaborative access securely and efficiently.

Pattern matching using regular expressions is a key troubleshooting and text-processing skill covered in CompTIA Linux+ V8. The grep command, combined with regular expressions, allows administrators to search for complex string patterns within files.

The requirement specifies:

The string must contain at least five characters

Character 2 must be i

Character 3 must not be b

Character 5 must be i

To meet these conditions, the correct regular expression structure is:

. → any character (position 1)

i → literal i (position 2)

[^b] → any character except b (position 3)

. → any character (position 4)

i → literal i (position 5)

This results in the expression:

i[^b].i

Option D, grep .i[^b].i myFile, correctly implements this logic. It ensures positional matching and excludes unwanted characters using a negated character class ([^b]), which is explicitly covered in Linux+ V8 regular expression objectives.

The other options contain invalid or malformed regular expressions and do not meet the positional or exclusion requirements. Linux+ V8 emphasizes understanding anchors, character classes, and position-based matching when troubleshooting log files or configuration data.

Therefore, the correct answer is D.

This scenario falls under the Security domain of the CompTIA Linux+ V8 objectives and focuses on system hardening and service minimization. The Nmap scan output reveals that port 23 (Telnet) is open on the system, which represents a significant security risk.

Telnet is an insecure, legacy protocol that transmits authentication credentials and session data in plaintext, making it vulnerable to interception through packet sniffing or man-in-the-middle attacks. Linux+ V8 documentation explicitly emphasizes the principle of least functionality, which states that unnecessary or insecure services should be disabled and removed entirely rather than merely restricted.

Option D, disabling and removing the Telnet service on the server, is the best and most secure solution. This action eliminates the vulnerable service completely, ensuring that it cannot be exploited internally or externally. In secure Linux environments, Telnet should be replaced with SSH, which provides encrypted communication and strong authentication mechanisms.

Option A, blocking port 23 with a firewall, reduces exposure but does not eliminate the underlying risk. If the firewall rules are misconfigured or bypassed, the Telnet service would still be available. Linux+ V8 best practices recommend removing insecure services rather than relying solely on perimeter controls.

Option B is unrelated, as changing passwords does not address the risk of plaintext credential transmission. Option C is incorrect because closing ports at the network switch level is not an appropriate or scalable solution for host-level service hardening and does not address internal access risks.

Linux+ V8 documentation consistently highlights service auditing, port scanning, and removal of insecure protocols as essential system hardening steps. Therefore, the most effective and secure remediation is to disable and remove the Telnet service.