CompTIA CompTIA Certifications XK0-005 Questions & Answers

• Question 131:

  A Linux administrator needs to connect securely to a remote server in order to install application software. Which of the following commands would allow this connection?

  A. scp "ABC-key.pem" [email protected]

  B. sftp rooteiO.0.0.1

  C. telnet 10.0.0.1 80

  D. ssh -i "ABC-key.pem" [email protected]

  E. sftp "ABC-key.pem" [email protected]

  Correct Answer: D

  Explanation: The command ssh -i "ABC-key.pem" [email protected] would allow the administrator to connect securely to the remote server in order to install application software. The ssh command is a tool for establishing secure and encrypted connections between remote systems. The -i option specifies the identity file that contains the private key for key-based authentication. The "ABC-key.pem" is the name of the identity file that contains the private key. The [email protected] is the username and the IP address of the remote server. The command ssh -i "ABC-key.pem" [email protected] will connect to the remote server using the private key and allow the administrator to install application software. This is the correct command to use to connect securely to the remote server. The other options are incorrect because they either do not use key-based authentication (sftp [email protected] or telnet 10.0.0.1 80) or do not use the correct syntax for the command (scp "ABC-key.pem" [email protected] instead of scp -i "ABC-key.pem" [email protected] or sftp "ABC-key.pem" [email protected] instead of sftp -i "ABC-key.pem" [email protected]). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 17: Implementing Basic Security, page 513.

• Question 132:

  A Linux administrator is creating a primary partition on the replacement hard drive for an application server. Which of the following commands should the administrator issue to verify the device name of this partition?

  A. sudo fdisk /dev/sda

  B. sudo fdisk -s /dev/sda

  C. sudo fdisk -l

  D. sudo fdisk -h

  Correct Answer: C

  Explanation: The command sudo fdisk -l should be issued to verify the device name of the partition. The sudo command allows the administrator to run commands as the superuser or another user. The fdisk command is a tool for manipulating disk partitions on Linux systems. The -l option lists the partitions on all disks or a specific disk. The command sudo fdisk -l will show the device names, sizes, types, and other information of the partitions on all disks. The administrator can identify the device name of the partition by looking at the output. This is the correct command to use to accomplish the task. The other options are incorrect because they either do not list the partitions (sudo fdisk /dev/sda or sudo fdisk -h) or do not exist (sudo fdisk -s /dev/sda). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 10: Managing Storage, page 317.

• Question 133:

  A systems administrator received a request to change a user's credentials. Which of the following commands will grant the request?

  A. sudo passwd

  B. sudo userde 1

  C. sudo chage

  D. sudo usermod

  Correct Answer: A

  Explanation: This command will allow the systems administrator to change the password of another user account in the system. The sudo prefix will grant the administrator the necessary privileges to perform this action, and the passwd

  command will prompt for the new password for the specified user. For example, if the administrator wants to change the password of a user named tom, the command will look like this:

  sudo passwd tom

  The other options are incorrect because:

  B. sudo userdel

  This command will delete a user account from the system, not change its credentials. The userdel command removes the user's entry from the /etc/passwd and /etc/shadow files, as well as deletes the user's home directory and mail spool.

  This is not what the request asked for.

  C. sudo chage

  This command will change the password expiration and aging information for a user account, not its credentials. The chage command can be used to set or modify various parameters related to password aging, such as the minimum and

  maximum number of days between password changes, the number of days before password expiration to issue a warning, and so on. This is not what the request asked for.

  D. sudo usermod

  This command will modify various attributes of a user account, such as its login name, home directory, default shell, primary group, and so on. However, it cannot change the user's password directly. To do that, the usermod command

  requires the -p option followed by an encrypted password string, which is not easy to generate manually. Therefore, this is not a practical way to change a user's credentials.

  References:

  How to Change Account Passwords on Linux

  How to Change a Password in Linux for Root and Other Users CompTIA Linux+ Certification Exam Objectives

• Question 134:

  A systems administrator creates a public key for authentication. Which of the following tools is most suitable to use when uploading the key to the remote servers?

  A. scp

  B. ssh-copy-id

  C. ssh-agent

  D. ssh-keyscan

  Correct Answer: B

  Explanation: The best tool to use when uploading the public key to the remote servers is B. ssh-copy-id. This tool will copy the public key from the local computer to the remote server and append it to the authorized_keys file, which is used for public key authentication. This tool will also create the necessary directories and files on the remote server if they do not exist. The other tools are either not suitable or not relevant for this task. For example: A. scp is a tool for securely copying files between hosts, but it does not automatically add the public key to the authorized_keys file. C. ssh-agent is a tool for managing private keys and passphrases, but it does not upload the public key to the remote server.

  D. ssh-keyscan is a tool for collecting public keys from remote hosts, but it does not upload the public key to the remote server.

• Question 135:

  A Linux administrator is troubleshooting an issue in which an application service failed to start on a Linux server. The administrator runs a few commands and gets the following outputs:

  

  Based on the above outputs, which of the following is the MOST likely action the administrator should take to resolve this issue?

  A. Enable the logsearch.service and restart the service.

  B. Increase the TimeoutStartUSec configuration for the logsearch.sevice.

  C. Update the OnCalendar configuration to schedule the start of the logsearch.service.

  D. Update the KillSignal configuration for the logsearch.service to use TERM.

  Correct Answer: B

  Explanation: The administrator should increase the TimeoutStartUSec configuration for the logsearch.service to resolve the issue. The output of systemct1 status logsearch.service shows that the service failed to start due to a timeout. The output of cat /etc/systemd/system/logsearch.service shows that the service has a TimeoutStartUSec configuration of 10 seconds, which might be too short for the service to start. The administrator should increase this value to a higher number, such as 30 seconds or 1 minute, and then restart the service. The other options are incorrect because they are not related to the issue. The service is already enabled, as shown by the output of systemct1 is-enabled logsearch.service. The service does not use an OnCalendar configuration, as it is not a timer unit. The service does not use a KillSignal configuration, as it is not being killed by a signal. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 14: Managing Processes and Scheduling Tasks, pages 434-435.

• Question 136:

  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

  Correct Answer: B

  Explanation: The command docker rm $(docker ps -aq) will allow the administrator to clean up the containers in an exited state. The docker command is a tool for managing Docker containers on Linux systems. Docker containers are isolated and lightweight environments that can run applications and services without affecting the host system. Docker uses images to create containers, which are files that contain the code, libraries, dependencies, and configuration of the applications and services. The rm option removes one or more containers. The $(docker ps -aq) is a command substitution that executes the command inside the parentheses and replaces it with the output. The docker ps - aq command lists all the containers, including the ones in an exited state, and shows only their IDs. The docker rm $(docker ps -aq) command will remove all the containers, including the ones in an exited state, by passing their IDs to the rm option. This will allow the administrator to clean up the containers in an exited state. This is the correct command to use to accomplish the task. The other options are incorrect because they either do not exist (docker rm --all or docker rm --state exited) or do not remove the containers (docker images prune *). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 19: Managing Cloud and Virtualization Technologies, page 571.

• Question 137:

  One leg of an LVM-mirrored volume failed due to the underlying physical volume, and a systems administrator is troubleshooting the issue. The following output has been provided:

  

  Given this scenario, which of the following should the administrator do to recover this volume?

  A. Reboot the server. The volume will automatically go back to linear mode.

  B. Replace the failed drive and reconfigure the mirror.

  C. Reboot the server. The volume will revert to stripe mode.

  D. Recreate the logical volume.

  Correct Answer: B

  Explanation: The administrator should replace the failed drive and reconfigure the mirror to recover the volume. The LVM (Logical Volume Manager) is a tool for managing disk space on Linux systems. The LVM allows the administrator to create logical volumes that span across multiple physical volumes, such as hard disks or partitions. The LVM also supports different types of logical volumes, such as linear, striped, or mirrored. A mirrored logical volume is a type of logical volume that creates a copy of the data on another physical volume, providing redundancy and fault tolerance. The output shows that the logical volume is mirrored and that one leg of the mirror has failed due to the underlying physical volume. This means that one of the physical volumes that contains the data of the logical volume is damaged or missing. This can cause data loss and performance degradation. The administrator should replace the failed drive and reconfigure the mirror to recover the volume. The administrator should identify the failed physical volume by using commands such as pvdisplay, vgdisplay, or lvdisplay. The administrator should then remove the failed physical volume from the volume group by using the vgreduce command. The administrator should then install a new drive and create a new physical volume by using the pvcreate command. The administrator should then add the new physical volume to the volume group by using the vgextend command. The administrator should then reconfigure the mirror by using the lvconvert command. The administrator should replace the failed drive and reconfigure the mirror to recover the volume. This is the correct answer to the question. The other options are incorrect because they either do not recover the volume (reboot the server. The volume will automatically go back to linear mode or reboot the server. The volume will revert to stripe mode) or do not preserve the data of the volume (recreate the logical volume). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 10: Managing Storage, pages 333-334.

• Question 138:

  A Linux engineer needs to download a ZIP file and wants to set the nice of value to -10 for this new process. Which of the following commands will help to accomplish the task?

  A. $ nice -v -10 wget https://foo.com/installation.zip

  B. $ renice -v -10 wget https://foo.com/installation.2ip

  C. $ renice -10 wget https://foo.com/installation.zip

  D. $ nice -10 wget https://foo.com/installation.zip

  Correct Answer: D

  Explanation: The nice -10 wget https://foo.com/installation.zip command will help to accomplish the task of downloading a ZIP file and setting the nice value to -10 for this new process. The nice command can be used to run a program with a

  modified scheduling priority, which affects how much CPU time the process receives. The nice value ranges from -20 (highest priority) to 19 (lowest priority), and the default value is 0. The -10 option specifies the nice value to be used for the

  wget command, which will download the ZIP file from the given URL. The nice -v -10 wget https://foo.com/installation.zip command is incorrect, as -v is not a valid option for nice. The renice -v -10 wget https://foo.com/installation.zip command

  is incorrect, as renice is used to change the priority of an existing process, not a new one. The renice -10 wget https://foo.com/installation.zip command is incorrect for the same reason as above. References: CompTIA Linux+ (XK0-005)

  Certification Study Guide, Chapter 15:

  Managing Memory and Process Execution, page 469.

• Question 139:

  A Linux administrator reviews a set of log output files and needs to identify files that contain any occurrence of the word denied. All log files containing entries in uppercase or lowercase letters should be included in the list. Which of the following commands should the administrator use to accomplish this task?

  A. find . -type f -print | xrags grep -ln denied

  B. find . -type f -print | xrags grep -nv denied

  C. find . -type f -print | xrags grep -wL denied

  D. find . -type f -print | xrags grep -li denied

  Correct Answer: D

  Explanation: The command find . -type f -print | xargs grep -li denied will accomplish the task of identifying files that contain any occurrence of the word denied. The find command is a tool for searching for files and directories on Linux systems. The . is the starting point of the search, which means the current directory. The -type f option specifies the type of the file, which means regular file. The -print option prints the full file name on the standard output. The | is a pipe symbol that redirects the output of one command to the input of another command. The xargs command is a tool for building and executing commands from standard input. The grep command is a tool for searching for patterns in files or input. The -li option specifies the flags that the grep command should apply. The -l flag shows only the file names that match the pattern, instead of the matching lines. The -i flag ignores the case of the pattern, which means it matches both uppercase and lowercase letters. The denied is the pattern that the grep command should search for. The command find . - type f -print | xargs grep -li denied will find all the regular files in the current directory and its subdirectories, and then search for any occurrence of the word denied in those files, ignoring the case, and print only the file names that match the pattern. This will allow the administrator to identify files that contain any occurrence of the word denied. This is the correct command to use to accomplish the task. The other options are incorrect because they either do not ignore the case of the pattern (find . -type f -print | xargs grep -ln denied or find . -type f -print | xargs grep -wL denied) or do not show the file names that match the pattern (find . -type f -print | xargs grep -nv denied). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 16: Managing Logging and Monitoring, page 489.

• Question 140:

  An administrator would like to list all current containers, regardless of their running state. Which of the following commands would allow the administrator to accomplish this task?

  A. docker ps -a

  B. docker list

  C. docker image ls

  D. docker inspect image

  Correct Answer: A

  The best command to use to list all current containers, regardless of their running state, is A. docker ps -a. This command will show all containers, both running and stopped, with details such as container ID, image name, status, and ports. The other commands are either invalid or not relevant for this task. For example:

  B. docker list is not a valid command. There is no subcommand named list in docker.

  C. docker image ls will list all the images available on the local system, not the containers.

  D. docker inspect image will show detailed information about a specific image, not all the containers.