CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 231:

  An administrator started a long-running process in the foreground that needs to continue without interruption. Which of the following keystrokes should the administrator use to continue running the process in the background?

  A. bg
  B. bg
  C. jobs -1
  D. bg and
  A. bg

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  Explanation

  A long-running process is a program that takes a long time to complete or runs indefinitely on a Linux system. A foreground process is a process that runs in the current terminal and receives input from the keyboard and output to the screen. A background process is a process that runs in the background and does not interact with the terminal. A background process can continue running even if the terminal is closed or disconnected. To start a long-running process in the background, the user can append an ampersand (and) to the command, such as someapp and. This will run someapp in the background and return control to the terminal immediately. To move a long-running process from the foreground to the background, the user can use two keystrokes: Ctrl+Z and bg. The Ctrl+Z keystroke will suspend (pause) the foreground process and return control to the terminal. The bg keystroke will resume (continue) the suspended process in the background and detach it from the terminal. The statement B is correct. The statements A, C, and D are incorrect because they do not perform the desired task. The bg keystroke alone will not work unless there is a suspended process to resume. The Ctrl+B keystroke will not suspend the foreground process, but rather move one character backward in some applications. The jobs keystroke will list all processes associated with the current terminal. The bg and keystroke will cause an error because bg does not take any arguments.

  References: [How to Run Linux Processes in Background]

• Question 232:

  An administrator needs to make some changes in the IaC declaration templates. Which of the following commands would maintain version control?

  A. git clone https://github.com/comptia/linux+-.git git push origin
  B. git clone https://qithub.com/comptia/linux+-.git git fetch New-Branch
  C. git clone https://github.com/comptia/linux+-.git git status
  D. git clone https://github.com/comptia/linuxt+-.git git checkout -b
  D. git clone https://github.com/comptia/linuxt+-.git git checkout -b

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  Explanation

  The command that will maintain version control while making some changes in the IaC declaration templates is git checkout -b . This command uses the git tool, which is a distributed version control system that tracks changes in source code and enables collaboration among developers. The checkout option switches to a different branch in the git repository, where a branch is a pointer to a specific commit in the history. The -b option creates a new branch with the given name, and switches to it. This way, the administrator can make changes in the new branch without affecting the main branch, and later merge them if needed. The other options are not correct commands for maintaining version control while making some changes in the IaC declaration templates. The git clone https://github.com/comptia/linux?git command will clone an existing repository from a remote URL to a local directory, but it will not create a new branch for making changes. The git push origin command will push the local changes to a remote repository named origin, but it will not create a new branch for making changes. The git fetch New-Branch command will fetch updates from a remote branch named New-Branch, but it will not create a new branch for making changes.

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 19: Managing Source Code; Git - Basic Branching and Merging

• Question 233:

  A Linux system fails to start and delivers the following error message:

  

  Which of the following commands can be used to address this issue?

  A. fsck.ext4 /dev/sda1
  B. partprobe /dev/sda1
  C. fdisk /dev/sda1
  D. mkfs.ext4 /dev/sda1
  A. fsck.ext4 /dev/sda1

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  Explanation

  The command fsck.ext4 /dev/sda1 can be used to address the issue. The issue is caused by a corrupted filesystem on the /dev/sda1 partition. The error message shows that the filesystem type is ext4 and the superblock is invalid. The command fsck.ext4 is a tool for checking and repairing ext4 filesystems. The command will scan the partition for errors and attempt to fix them. This command can resolve the issue and allow the system to start. The other options are incorrect because they either do not fix the filesystem (partprobe or fdisk) or destroy the data on the partition (mkfs.ext4).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter

  10: Managing Storage, page 325.

• Question 234:

  A Linux administrator tries to install Ansible in a Linux environment. One of the steps is to change the owner and the group of the directory /opt/Ansible and its contents. Which of the following commands will accomplish this task?

  A. groupmod -g Ansible -n /opt/Ansible
  B. chown -R Ansible:Ansible /opt/Ansible
  C. usermod -aG Ansible /opt/Ansible
  D. chmod -c /opt/Ansible
  B. chown -R Ansible:Ansible /opt/Ansible

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  Explanation

• Question 235:

  An administrator attempts to connect to a remote server by running the following command:

  $ nmap 192.168.10.36

  Starting Nmap 7.60 ( https://nmap.org ) at 2022-03-29 20:20 UTC

  Nmap scan report for www1 (192.168.10.36)

  Host is up (0.000091s latency).

  Not shown: 979 closed ports

  PORT STATE SERVICE

  21/tcp open ftp

  22/tcp filtered ssh

  631/tcp open ipp

  Nmap done: 1 IP address (1 host up) scanned in 0.06 seconds

  Which of the following can be said about the remote server?

  A. A firewall is blocking access to the SSH server.
  B. The SSH server is not running on the remote server.
  C. The remote SSH server is using SSH protocol version 1.
  D. The SSH host key on the remote server has expired.
  A. A firewall is blocking access to the SSH server.

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  Explanation

  This is because the port 22/tcp is shown as filtered by nmap, which means that nmap cannot determine whether the port is open or closed because a firewall or other device is blocking its probes. If the SSH server was not running on the remote server, the port would be shown as closed, which means that nmap received a TCP RST packet in response to its probe. If the remote SSH server was using SSH protocol version 1, the port would be shown as open, which means that nmap received a TCP SYN/ACK packet in response to its probe. If the SSH host key on the remote server had expired, the port would also be shown as open, but the SSH client would display a warning message about the host key verification failure. Therefore, the best explanation for the filtered state of the port 22/tcp is that a firewall is preventing nmap from reaching the SSH server. You can find more information about nmap port states and how to interpret them in the following web search results: Nmap scan what does STATE=filtered mean? How to find ports marked as filtered by nmap Technical Tip: NMAP scan shows ports as filtered

• Question 236:

  User1 is a member of the accounting group. Members of this group need to be able to execute but not make changes to a script maintained by User2. The script should not be accessible to other users or groups. Which of the following will give proper access to the script?

  A. chown user2:accounting script.sh chmod 750 script.sh
  B. chown user1:accounting script.sh chmod 777 script.sh
  C. chown accounting:user1 script.sh chmod 057 script.sh
  D. chown user2:accounting script.sh chmod u+x script.sh
  A. chown user2:accounting script.sh chmod 750 script.sh

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  Explanation

  The commands that will give proper access to the script are: chown user2:accounting script.sh: This command will change the ownership of the script to user2 as the owner and accounting as the group. The chown command is a tool for changing the owner and group of files and directories on Linux systems. The user2:accounting is the user and group name that the command should assign to the script. The script.sh is the name of the script that the command should modify. The command chown user2:accounting script.sh will ensure that user2 is the owner of the script and accounting is the group of the script, which will allow user2 to maintain the script and the accounting group to access the script. chmod 750 script.sh: This command will change the permissions of the script to 750, which means read, write, and execute for the owner; read and execute for the group; and no access for others. The chmod command is a tool for changing the permissions of files and directories on Linux systems. The permissions are represented by three digits in octal notation, where each digit corresponds to the owner, group, and others. Each digit can have a value from 0 to 7, where each value represents a combination of read, write, and execute permissions. The 750 is the permission value that the command should assign to the script. The script.sh is the name of the script that the command should modify. The command chmod 750 script.sh will ensure that only the owner and the group can execute the script, but not make changes to it, and that the script is not accessible to other users or groups. The commands that will give proper access to the script are chown user2:accounting script.sh and chmod 750 script.sh. This is the correct answer to the question. The other options are incorrect because they either do not give proper access to the script (chown user1:accounting script.sh or chown accounting:user1 script.sh) or do not change the permissions of the script (chmod 777 script.sh or chmod u+x script.sh).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 11: Managing File Permissions and Ownership, pages 346-348.

• Question 237:

  A systems administrator is installing various software packages using a pack-age manager. Which of the following commands would the administrator use on the Linux server to install the package?

  A. winget
  B. softwareupdate
  C. yum-config
  D. apt
  D. apt

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  Explanation

• Question 238:

  The application team has reported latency issues that are causing the application to crash on the Linux server. The Linux administrator starts

  troubleshooting and receives the following output:

  

  Which of the following commands will improve the latency issue?

  A. # echo 'net.core.net_backlog = 5000000' >> /etc/sysctl.conf # sysctl -p # systemctl daemon-reload
  B. # ifdown eth0 # ip link set dev eth0 mtu 800 # ifup eth0
  C. # systemctl stop network # ethtool -g eth0 512 # systemctl start network
  D. # echo 'net.core.rmem max = 12500000' >> /etc/sysctl.conf # echo 'net.core.wmem_max = 12500000' >> /etc/sysctl.conf # sysctl -p
  D. # echo 'net.core.rmem max = 12500000' >> /etc/sysctl.conf # echo 'net.core.wmem_max = 12500000' >> /etc/sysctl.conf # sysctl -p

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  Explanation

  The best command to use to improve the latency issue is

  D. # echo `net.core.rmem max = 12500000' >> /etc/sysctl.conf # echo `net.core.wmem_max = 12500000' >> /etc/sysctl.conf # sysctl -p. This command will increase the size of the

  receive and send buffers for the network interface, which can improve the network performance and reduce packet loss. The sysctl command will apply the changes to the kernel parameters without rebooting the system.

  The other commands are either incorrect or not suitable for this task. For example:

  A. # echo `net.core.net_backlog = 5000000' >> /etc/sysctl.conf # sysctl -p # systemctl daemon-reload will try to increase the backlog queue for incoming connections, but this is not relevant for the latency issue. The systemctl daemon- reload command is also unnecessary, as it only reloads the systemd configuration files, not the kernel parameters.

  B. # ifdown eth0 # ip link set dev eth0 mtu 800 # ifup eth0 will try to change the maximum transmission unit (MTU) of the network interface to 800 bytes, but this is too low and may cause fragmentation and performance degradation. The default MTU for Ethernet is 1500 bytes, and it should not be changed unless there is a specific reason.

  C. # systemctl stop network # ethtool -g eth0 512 # systemctl start network will try to change the ring buffer size of the network interface to 512, but this is too small and may cause packet drops and latency spikes. The default ring buffer size for Ethernet is usually 4096 or higher, and it should be increased if there is a high network traffic.

• Question 239:

  A systems administrator wants to check if the ntpd service is configured to start on startup. Which of the following commands will show that information when run?

  A. systemctl is-active ntpd.service
  B. systemctl stop ntpd.service
  C. systemctl is-enabled ntpd.service
  D. systemctl start ntpd.service
  C. systemctl is-enabled ntpd.service

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  Explanation

• Question 240:

  Which of the following best describes JSON?

  A. A programming language that developers use to build dynamic websites
  B. An open-source platform that facilitates the creation and administration of isolated environments
  C. A file format for exchanging information or data between systems
  D. A software-based technique that allows a computer to simulate one or more machines so they appear to be real
  C. A file format for exchanging information or data between systems

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  Explanation