CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 251:

  A Linux administrator is updating the file that contains the addresses of the software and update repositories on an Ubuntu system. Which of the following files needs to be edited to accomplish this task?

  A. /etc/apt/sources.list
  B. /etc/apt/listchanges.conf
  C. /etc/yum/yum.conf
  D. /etc/dnf/dnf.conf
  A. /etc/apt/sources.list

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  Explanation

• Question 252:

  An administrator needs to stop a foreground process in between its execution in a terminal. Which of the following should the administrator use?

  A. Ctrl+D
  B. Ctrl+F
  C. Ctrl+Z
  D. Ctrl+C
  D. Ctrl+C

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  Explanation

• Question 253:

  After connecting to a remote host via SSH, an administrator attempts to run an application but receives the following error:

  [user@workstation ~]$ ssh admin@srv1

  Last login: Tue Mar 29 18:03:34 2022

  [admin@srvl ~] $ /usr/local/bin/config_manager

  Error: cannot open display:

  [admin@srv1 ~] $

  Which of the following should the administrator do to resolve this error?

  A. Disconnect from the SSH session and reconnect using the ssh -x command.
  B. Add Options X11 to the /home/admin/.ssh/authorized_keys file.
  C. Open port 6000 on the workstation and restart the firewalld service.
  D. Enable X11 forwarding in /etc/ssh/ssh_config and restart the server.
  A. Disconnect from the SSH session and reconnect using the ssh -x command.

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  Explanation

  The error indicates that the application requires an X11 display, but the SSH session does not forward the X11 connection. To enable X11 forwarding, the administrator needs to use the ssh -X option, which requests X11 forwarding with authentication spoofing. This will set the DISPLAY environment variable on the remote host and allow the application to open a window on the local display.

  References

  CompTIA Linux+ (XK0-005) Certification Study Guide, page 314 Open a window on a remote X display (why "Cannot open display")?, answer by Gilles `SO- stop being evil'

• Question 254:

  A Linux engineer is setting the sticky bit on a directory called devops with 755 file permission. Which of the following commands will accomplish this task?

  A. chown -s 755 devops
  B. chown 1755 devops
  C. chmod -s 755 devops
  D. chmod 1755 devops
  D. chmod 1755 devops

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  Explanation

  The command that will set the sticky bit on a directory called devops with 755 file permission is chmod 1755 devops. This command will use chmod to change the mode of the directory devops to 1755, which means that the owner has read, write, and execute permissions (7), the group has read and execute permissions (5), and others have read and execute permissions (5). The first digit 1 indicates that the sticky bit is set on the directory, which is a special permission that prevents users from deleting or renaming files in the directory that they do not own. The other options are not correct commands for setting the sticky bit on a directory. The chown -s 755 devops command is invalid because chown is used to change the owner and group of files or directories, not their permissions. The -s option for chown is used to remove a symbolic link, not to set the sticky bit. The chown 1755 devops command is also invalid because chown does not accept numeric arguments for changing permissions. The chmod -s 755 devops command will remove the sticky bit from the directory devops, not set it.

  References: chmod(1) - Linux manual page; How to Use SUID, SGID, and Sticky Bits on Linux

• Question 255:

  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?

  A. ip show
  B. ifcfg --a
  C. ifcfg --s
  D. i fname --s
  B. ifcfg --a

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  Explanation

  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]

• Question 256:

  A new application container was built with an incorrect version number. Which of the following commands should be used to rename the image to match the correct version 2.1.2?

  A. docker tag comptia/app:2.1.1 comptia/app:2.1.2
  B. docker push comptia/app:2.1.1 comptia/app:2.1.2
  C. docker rmi comptia/app:2.1.1 comptia/app:2.1.2
  D. docker update comptia/app:2.1.1 comptia/app:2.1.2
  A. docker tag comptia/app:2.1.1 comptia/app:2.1.2

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  Explanation

  The best command to use to rename the image to match the correct version 2.1.2 is A. docker tag comptia/app:2.1.1 comptia/app:2.1.2. This command will create a new tag for the existing image with the new version number, without changing the image content or ID. The other commands are either incorrect or not suitable for this task. For example:

  B. docker push comptia/app:2.1.1 comptia/app:2.1.2 will try to push two images to a remote repository, but it does not rename the image locally.

  C. docker rmi comptia/app:2.1.1 comptia/app:2.1.2 will try to remove two images from the local system, but it does not rename the image.

  D. docker update comptia/app:2.1.1 comptia/app:2.1.2 will try to update the configuration of a running container, but it does not rename the image.

• Question 257:

  A systems administrator is reconfiguring existing user accounts in a Linux system. Which of the following commands should the administrator use to include "myuser" in the finance group?

  A. groupadd finance myuser
  B. groupmod finance myuser
  C. useradd -g finance myuser
  D. usermod -aG finance myuser
  D. usermod -aG finance myuser

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  Explanation

• Question 258:

  A Linux administrator is installing a web server and needs to check whether web traffic has already been allowed through the firewall. Which of the following commands should the administrator use to accomplish this task?

  A. firewalld query-service-http
  B. firewall-cmd --check-service http
  C. firewall-cmd --query-service http
  D. firewalld --check-service http
  C. firewall-cmd --query-service http

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  Explanation

  The command firewall-cmd --query-service http will accomplish the task of checking whether web traffic has already been allowed through the firewall. The firewall- cmd command is a tool for managing firewalld, which is a firewall service that provides dynamic and persistent network security on Linux systems. The firewalld uses zones and services to define the rules and policies for the network traffic. The zones are logical groups of network interfaces and sources that have the same level of trust and security. The services are predefined sets of ports and protocols that are associated with certain applications or functions. The --query-service http option queries whether a service is enabled in a zone. The http is the name of the service that the command should check. The http service represents the web traffic that uses the port 80 and the TCP protocol. The command firewall-cmd --query-service http will check whether the http service is enabled in the default zone, which is usually the public zone. The command will return yes if the web traffic has already been allowed through the firewall, or no if the web traffic has not been allowed through the firewall. This is the correct command to use to accomplish the task. The other options are incorrect because they either do not exist (firewalld query-service- http or firewalld --check-service http) or do not query the service (firewall-cmd --check- service http instead of firewall-cmd --queryservice http).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 392.

• Question 259:

  A systems administrator created a new Docker image called test. After building the image, the administrator forgot to version the release. Which of the following will allow the administrator to assign the v1 version to the image?

  A. docker image save test test:v1
  B. docker image build test:vl
  C. docker image tag test test:vl
  D. docker image version test:v1
  C. docker image tag test test:vl

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  Explanation

  The docker image tag test test:v1 command can be used to assign the v1 version to the image called test. This command creates a new tag for the existing image, without changing the original image. The docker image save test test:v1 command would save the image to a file, not assign a version. The docker image build test:vl command is invalid, as vl is not a valid version number. The docker image version test:v1 command does not exist.

  References: [CompTIA Linux+ (XK0-005) Certification Study Guide], Chapter 16: Virtualization and Cloud Technologies, page 500.

• Question 260:

  A hardened physical Linux system allows regular, unprivileged users to remotely connect to the server using SSH only. No sudo tool has been installed. Which of the following should the Linux administrator use to perform administrative tasks on this host? (Select two).

  A. Create an SSH key and copy it to the remote server to allow passwordless login
  B. Access the server's physical console and use the root user's password to log in
  C. Install the telnet server on this system to be able to use a root account
  D. Use the su command and enter the root user's password
  E. Install the sudo command using the unprivileged user's account
  F. Add the user to the wheel group
  B. Access the server's physical console and use the root user's password to log in
  D. Use the su command and enter the root user's password

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  Explanation

  As the sudo tool is not installed on the system, administrative tasks must be performed either via direct physical console access or by switching to the root user using the su command. Both methods require knowledge of the root password. Installing Telnet is not a good option due to its lack of security, and installing sudo using an unprivileged user is not possible without root privileges.