CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 391:

  A Linux administrator needs to create a symlink for /usr/local/bin/app-a, which was installed in /usr/local/share/app-a. Which of the following commands should the administrator use?

  A. In -s /usr/local/bin/app-a /usr/local/share/app-a
  B. mv -f /usr/local/share/app-a /usr/local/bin/app-a
  C. cp -f /usr/local/share/app-a /usr/local/bin/app-a
  D. rsync -a /usr/local/share/app-a /usr/local/bin/app-a
  A. In -s /usr/local/bin/app-a /usr/local/share/app-a

  ---

  Explanation

  To create a symlink for /usr/local/bin/app-a, which was installed in /usr/local/share/app-a, the administrator can use the command ln -s /usr/local/share/app-a /usr/local/bin/app-a (A). This will create a symbolic link named /usr/local/bin/app-a that points to the original file /usr/local/share/app-a. The other commands will not create a symlink, but either move, copy, or synchronize the file.

  References:

  [CompTIA Linux+ Study Guide], Chapter 3: Working with Files, Section: Creating Links

  [How to Create Symbolic Links in Linux]

• Question 392:

  A systems administrator wants to ensure all the latest patches and updates are automatically synced to the local repository every two hours on Sundays through Tuesdays in the month of May. Which of the following cron entries can the administrator use to achieve this goal? (Select two.)

  A. 0 */2 * 5 0-2 /root/update-from-remote-to-local.sh
  B. 0 0,2,4,6,8,10,12,14 * 5 0-2 /root/update-from-remote-to-local.sh
  C. 0 0,2,4,6,8,10,12,14 * 5 0-3 /root/update-from-remote-to-local.sh
  D. 0 0-23/2 * 5 0-3 /root/update-from-remote-to-local.sh
  E. 0 0-23/2 * 5 0-2 /root/update-from-remote-to-local.sh
  F. 0 */2 * 5 0-2 /root/update-from-remote-to-local.sh
  A. 0 */2 * 5 0-2 /root/update-from-remote-to-local.sh
  C. 0 0,2,4,6,8,10,12,14 * 5 0-3 /root/update-from-remote-to-local.sh

  ---

  Explanation

• Question 393:

  A user created the following script file:

  # ! /bin/bash

  # FILENAME: /home/user/ script . sh

  echo "hello world"

  exit 1

  However, when the user tried to run the script file using the command "script . sh, an error returned indicating permission was denied. Which of the follow-ing should the user execute in order for the script to run properly?

  A. chmod u+x /home/user/script . sh
  B. chmod 600 /home/user/script . sh
  C. chmod /home/user/script . sh
  D. chmod 0+r /horne/user/script. sh
  A. chmod u+x /home/user/script . sh

  ---

  Explanation

  To run a script file, the user needs to have execute permission on the file. The command chmod u+x /home/user/script.sh (A) will grant execute permission to the owner of the file, which is the user who created it. The other commands will not give execute permission to the user, and therefore will not allow the script to run properly.

  References:

  [CompTIA Linux+ Study Guide], Chapter 3: Working with Files, Section: Changing File Permissions

  [How to Make a Bash Script Executable]

• Question 394:

  An administrator wants to reorganize the /etc/sudoers configuration file by department groups. Which of the following actions should the administrator take?

  A. Configure #includedir /etc/sudoers.d directive inside /etc/sudoers file.
  B. Create a symlink in each user's home directory to /etc/sudoers.
  C. Copy /etc/sudoers and name each group with incremental numbers (/etc/sudoers1, /etc/sudoers2).
  D. Execute setfacl commands on /etc/sudoers and add permissions for each group.
  A. Configure #includedir /etc/sudoers.d directive inside /etc/sudoers file.

  ---

  Explanation

• Question 395:

  Users are reporting that writes on a system configured with SSD drives have been taking longer than expected, but reads do not seem to be affected. A Linux systems administrator is investigating this issue and working on a solution. Which of the following should the administrator do to help solve the issue?

  A. Run the corresponding command to trim the SSD drives.
  B. Use fsck on the filesystem hosted on the SSD drives.
  C. Migrate to high-density SSD drives for increased performance.
  D. Reduce the amount of files on the SSD drives.
  A. Run the corresponding command to trim the SSD drives.

  ---

  Explanation

  TRIM is a feature that allows the operating system to inform the SSD which blocks of data are no longer in use and can be wiped internally. This helps to maintain the SSD's performance and endurance by preventing unnecessary write operations and reducing write amplification12. Running the corresponding command to trim the SSD drives, such as fstrim or blkdiscard on Linux, can help to solve the issue of slow writes by freeing up space and optimizing the SSD's internal garbage collection34.

  References:

  1: What is SSD TRIM, why is it useful, and how to check whether it is turned on

  2: How to Trim SSD in Windows 10

  3: How to run fsck on an external drive with OS X?

  4: How to Use the fsck Command on Linux

• Question 396:

  A Linux server is not starting up because files in the /boot/ partition are corrupt. After the initial GRUB screen, the following message is displayed:

  Probing EDD (edd=off to disable)... ok Uncompression error -- System halted

  Which of the following steps should the Linux administrator take to recover the system without destroying the existing installation? (Select two.)

  A. Replace the hard drive.
  B. Increase the amount of swap memory.
  C. Start up in single-user mode.
  D. Start up the system using rescue boot media.
  E. Reinstall the kernel packages.
  F. Reinstall the OS.
  D. Start up the system using rescue boot media.
  E. Reinstall the kernel packages.

  ---

  Explanation

• Question 397:

  A technician wants to temporarily use a Linux virtual machine as a router for the network segment 10.10.204.0/24. Which of the following commands should the technician issue? (Select three).

  A. echo "1" > /proc/sys/net/ipv4/ip_forward
  B. iptables -A FORWARD -j ACCEPT
  C. iptables -A PREROUTING -j ACCEPT
  D. iptables -t nat -s 10.10.204.0/24 -p tcp -A PREROUTING -j MASQUERADE
  E. echo "0" > /proc/sys/net/ipv4/ip_forward
  F. echo "1" > /proc/net/tcp
  G. iptables -t nat -s 10.10.204.0/24 -A POSTROUTING -j MASQUERADE
  H. iptables -t nat -A PREROUTING -j MASQUERADE
  A. echo "1" > /proc/sys/net/ipv4/ip_forward
  B. iptables -A FORWARD -j ACCEPT
  G. iptables -t nat -s 10.10.204.0/24 -A POSTROUTING -j MASQUERADE

  ---

  Explanation

• Question 398:

  A new hard drive /dev/sdd was added to a server.

  Which of the following commands will create a partition table with a single partition /dev/sdd1 that consumes the entire disk?

  A. echo 'type=83' | sudo sfdisk /dev/sdd
  B. sudo sfdisk /dev/sdd -t=83
  C. echo 'auto' | sudo fdisk /dev/sdd
  D. sudo fdisk /dev/sdd -1 -t=83
  A. echo 'type=83' | sudo sfdisk /dev/sdd

  ---

  Explanation

  The sfdisk tool is used to manipulate partition tables in Linux. Option A creates a single partition on /dev/sdd of type 83 (Linux filesystem).

• Question 399:

  An administrator added the port 2222 for the SSH server on myhost and restarted the SSH server. The administrator noticed issues during the startup of the service. Given the following outputs:

  

  Which of the following commands will fix the issue?

  A. semanage port -a -t ssh_port_t -p tcp 2222
  B. chcon system_u:object_r:ssh_home_t /etc/ssh/*
  C. iptables -A INPUT -p tcp -- dport 2222 -j ACCEPT
  D. firewall-cmd -- zone=public -- add-port=2222/tcp
  A. semanage port -a -t ssh_port_t -p tcp 2222

  ---

  Explanation

  The correct answer is A. semanage port -a -t ssh_port_t -p tcp 2222 This command will allow the SSH server to bind to port 2222 by adding it to the SELinux policy. The semanage command is a utility for managing SELinux policies. The port subcommand is used to manage network port definitions. The -a option is used to add a new record, the -t option is used to specify the SELinux type, the -p option is used to specify the protocol, and the tcp 2222 argument is used to specify the port number. The ssh_port_t type is the default type for SSH ports in SELinux.

  The other options are incorrect because:

  B. chcon system_u:object_r:ssh_home_t /etc/ssh/*

  This command will change the SELinux context of all files under /etc/ssh/ to system_u:object_r:ssh_home_t, which is not correct. The ssh_home_t type is used for user home directories that are accessed by SSH, not for SSH configuration files. The correct type for SSH configuration files is sshd_config_t.

  C. iptables -A INPUT -p tcp --dport 2222 -j ACCEPT This command will add a rule to the iptables firewall to accept incoming TCP connections on port 2222. However, this is

  not enough to fix the issue, as SELinux will still block the SSH server from binding to that port. Moreover, iptables may not be the default firewall service on some Linux distributions, such as Fedora or CentOS, which use firewalld instead.

  D. firewall-cmd --zone=public --add-port=2222/tcp

  This command will add a rule to the firewalld firewall to allow incoming TCP connections on port 2222 in the public zone. However, this is not enough to fix the issue, as SELinux will still block the SSH server from binding to that port.

  Moreover, firewalld may not be installed or enabled on some Linux distributions, such as Ubuntu or Debian, which use iptables instead.

  References:

  How to configure SSH to use a non-standard port with SELinux set to enforcing Change SSH Port on CentOS/RHEL/Fedora With SELinux Enforcing How to change SSH port when SELinux policy is enabled

• Question 400:

  Ann, a security administrator, is performing home directory audits on a Linux server. Ann issues the su Joe command and then issues the Is command. The output displays files that reside in Ann's home directory instead of Joe's. Which of the following represents the command Ann should have issued in order to list Joe's files?

  A. su - Joe
  B. sudo Joe
  C. visudo Joe
  D. pkexec joe
  A. su - Joe

  ---

  Explanation

  The su command is used to switch to another user account on Linux systems. The - option makes the shell a login shell, which means that it will read the profile and environment variables of the target user. Without this option, the shell will retain the environment variables of the original user. This can cause confusion when issuing commands that depend on these variables, such as ls, which uses the $HOME variable to determine the home directory. Therefore, Ann should have issued su - Joe to list Joe's files instead of her own.

  References: [How to Use su Command in Linux with Examples]