CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 91:

  A Linux engineer needs to get information from the foo.com domain mail servers. Which of the following network tools should the engineer use?

  A. arp mx foo.com
  B. nc mx foo.com
  C. dig mx foo.com
  D. route mx foo.com
  C. dig mx foo.com

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  Explanation

  To query Mail Exchange (MX) records for a domain, use dig:dig mx foo.com MX records specify which mail servers handle email for a domain.

• Question 92:

  A systems administrator wants to list all local accounts in which the UID is greater than 500. Which of the following commands will give the correct output?

  A. find /etc/passwd --size +500
  B. cut --d: fl / etc/ passwd > 500
  C. awk -F: `$3 > 500 {print $1}' /etc/passwd
  D. sed '/UID/' /etc/passwd < 500
  C. awk -F: `$3 > 500 {print $1}' /etc/passwd

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  Explanation

  The correct command to list all local accounts in which the UID is greater than 500 is:

  awk -F: '$3 > 500 {print $1}' /etc/passwd

  This command uses awk to process the /etc/passwd file, which contains information about the local users on the system. The -F: option specifies that the fields are separated by colons. The $3 refers to the third field, which is the UID. The condition $3 > 500 filters out the users whose UID is greater than 500. The action {print $1} prints the first field, which is the username.

  The other commands are incorrect because:

  find /etc/passwd --size +500 will search for files that are larger than 500 blocks in size, not users with UID greater than 500.

  cut --d: fl / etc/ passwd > 500 will cut the first field of the /etc/passwd file using colon as the delimiter, but it will not filter by UID or print only the usernames. The > 500 part will redirect the output to a file named 500, not compare with the UID.

  sed '/UID/' /etc/passwd < 500 will use sed to edit the /etc/passwd file and replace any line that contains UID with 500, not list the users with UID greater than 500. The < 500 part will redirect the input from a file named 500, not compare with the UID.

  References:

  Linux List All Users In The System Command - nixCraft, section "List all users in Linux using /etc/passwd file".

  Unix script getting users with UID bigger than 500 - Stack Overflow, section "Using awk".

• Question 93:

  A DevOps engineer needs to download a Git repository from https://git.company.com/admin/project.git. Which of the following commands will achieve this goal?

  A. git clone https://git.company.com/admin/project.git
  B. git checkout https://git.company.com/admin/project.git
  C. git pull https://git.company.com/admin/project.git
  D. git branch https://git.company.com/admin/project.git
  A. git clone https://git.company.com/admin/project.git

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  Explanation

  The command git clone https://git.company.com/admin/project.git will achieve the goal of downloading a Git repository from the given URL. The git command is a tool for managing version control systems. The clone option creates a copy of an existing repository. The URL specifies the location of the repository to clone, in this case https://git.company.com/admin/project.git. The command git clone https://git.company.com/admin/project.git will download the repository and create a directory named project in the current working directory. This is the correct command to use to accomplish the goal. The other options are incorrect because they either do not download the repository (git checkout, git pull, or git branch) or do not use the correct syntax (git checkout https://git.company.com/admin/project.git instead of git checkout -b project https://git.company.com/admin/project.git or git branch https://git.company.com/admin/project.git instead of git branch project https://git.company.com/admin/project.git).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 19: Managing Cloud and Virtualization Technologies, page 571.

• Question 94:

  A systems administrator receives the following message after running an ip link command to verify the status of a network interface named enp0s3:

  state DOWN

  Which of the following commands should the administrator use to resolve this issue?

  A. ip link set enp0s3 up
  B. ip link ifb enp0s3 up
  C. ip link add enp0s3 up
  D. ip link enp0s3 up
  A. ip link set enp0s3 up

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  Explanation

• Question 95:

  A Linux administrator found many containers in an exited state. Which of the following commands will allow the administrator to clean up the containers in an exited state?

  A. docker rm -- all
  B. docker rm $ (docker ps -aq)
  C. docker images prune *
  D. docker rm -- state exited
  B. docker rm $ (docker ps -aq)

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  Explanation

  This command will remove all containers, regardless of their state, by passing the IDs of all containers to the docker rm command. The docker ps -aq command will list the IDs of all containers, including the ones in an exited state, and the $ ( )

  syntax will substitute the output of the command as an argument for the docker rm command. This is a quick and easy way to clean up all containers, but it may also remove containers that are still needed or running.

  References

  docker rm | Docker Docs - Docker Documentation, section "Remove all containers" Docker Remove Exited Containers | Easy methods. - Bobcares, section "For removing all exited containers"

• Question 96:

  A systems administrator needs to check the size of the filesystem on the current application servers and ensure that the following filesystems are mounted:

  /var /var/log/audit /tmp /home/application

  Which of the following commands should the administrator use for these tasks?

  A. fdisk
  B. df
  C. du
  D. lsblk
  B. df

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  Explanation

• Question 97:

  A Linux engineer has been notified about the possible deletion of logs from the file /opt/app/logs. The engineer needs to ensure the log file can only be written into without removing previous entries.

  

  Which of the following commands would be BEST to use to accomplish this task?

  A. chattr +a /opt/app/logs
  B. chattr +d /opt/app/logs
  C. chattr +i /opt/app/logs
  D. chattr +c /opt/app/logs
  A. chattr +a /opt/app/logs

  ---

  Explanation

  The command chattr +a /opt/app/logs will ensure the log file can only be written into without removing previous entries. The chattr command is a tool for changing file attributes on Linux file systems. The +a option sets the append-only attribute, which means that the file can only be opened in append mode for writing. This prevents the file from being modified, deleted, or renamed. This is the best command to use to accomplish the task. The other options are incorrect because they either set the wrong attributes (+d, +i, or +c) or do not affect the file at all (-a).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 11: Managing Files and Directories, page 357.

• Question 98:

  A Linux administrator wants to display a list of all containers, including ones that are stopped. Which of the following commands should the administrator run?

  A. docker ps -a
  B. docker image list
  C. docker stats
  D. docker list -a
  A. docker ps -a

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  Explanation

• Question 99:

  Joe, a user, is unable to log in to the Linux system Given the following output:

  

  Which of the following command would resolve the issue?

  A. usermod -s /bin/bash joe
  B. pam_tally2 -u joe -r
  C. passwd -u joe
  D. chage -E 90 joe
  B. pam_tally2 -u joe -r

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  Explanation

  Based on the output of the image sent by the user, Joe is unable to log in to the Linux system because his account has been locked due to too many failed login attempts. The pam_tally2 -u joe -r command will resolve this issue by resetting Joe's failed login counter to zero and unlocking his account. This command uses the pam_tally2 module to manage user account locking based on login failures. The usermod -s /bin/bash joe command will change Joe's login shell to /bin/ bash, but this will not unlock his account. The passwd -u joe command will unlock Joe's password if it has been locked by passwd -l joe, but this will not reset his failed login counter or unlock his account if it has been locked by pam_tally2. The chage -E 90 joe command will set Joe's account expiration date to 90 days from today, but this will not unlock his account or reset his failed login counter.

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 18: Securing Linux Systems, page 537.

• Question 100:

  Which of the following will prevent non-root SSH access to a Linux server?

  A. Creating the /etc/nologin file
  B. Creating the /etc/nologin.allow file containing only a single line root
  C. Creating the /etc/nologin/login.deny file containing a single line +all
  D. Ensuring that /etc/pam.d/sshd includes account sufficient pam_nologin.so
  A. Creating the /etc/nologin file

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  Explanation

  This file prevents any non-root user from logging in to the system, regardless of the authentication method. The contents of the file are displayed to the user before the login is terminated. This can be useful for system maintenance or security reasons12.

  References: 1: Creating the /etc/nologin File - Oracle 2: How to Restrict Log In Capabilities of Users on Ubuntu