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6 free, original PBQs for Linux+ (XK0-006), with the Linux command line and drag-and-drop. Do each task, check it, and read why the answer is right.
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CompTIA Linux+
You do each task instead of picking an answer. Every question is explained after you check it, and you get a score at the end.
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The questions
Each one with its scenario and task. Try it above first, then open the explanation.
Question 1 · Linux command line · System Management
The payments application on app01 logged errors this morning, and its log folder is filling up. You’ve been asked how many errors there were, and to move the rotated log out of the way into an archive folder that doesn’t exist yet.
Answer the question from the log, then create the archive folder and move the old log into it.
grep -c counts the lines that match instead of printing them. /var belongs to root, so creating a folder there needs sudo, and -p creates /var/archive on the way to /var/archive/app. mv moves the rotated log, and mode 444 makes the archived copy read-only for everyone, so it can’t be edited by accident.
Question 2 · Linux command line · Services and User Management
Dana joins the data team today and needs an account on db01, in a new group called analysts. While you’re there, the PostgreSQL service, which was installed yesterday, has to be started and set to come up at boot.
Create the group and the account, then start and enable the service.
groupadd creates the group and useradd creates the account; -m gives it a home directory and -s sets the shell. usermod -aG adds a group without removing the others: without -a, -G replaces the whole list. systemctl enable --now does two jobs in one command: it starts the service and sets it to start at every boot.
Question 3 · Linux command line · Security
You copied your SSH keys to web01 from a USB stick, and now the SSH client refuses to use the private key: “permissions are too open”. Everything in ~/.ssh came across readable by every user on the server.
Look at the permissions in ~/.ssh, then set the ones SSH expects.
SSH refuses a private key that other users could read, because anyone holding it can sign in as you. The .ssh folder should be 700, so only you can enter it. The private key and authorized_keys should be 600: read and write for you, nothing for anyone else. The public key (.pub) is meant to be shared, so 644 is fine.
Question 4 · Matching · Security
A hardening checklist gives file modes as numbers, but ls -l shows them as letters. You need to read one as the other without stopping to think.
Match each permission string to its octal mode.
Each group of three letters is one digit: read is 4, write is 2 and execute is 1, added together. So rwx is 7, r-x is 5, rw- is 6, r-- is 4 and --- is 0. The three digits are the owner, the group and everyone else, in that order: rwxr-x--- is 7, 5, 0.
Question 5 · Ordering · Automation, Orchestration, and Scripting
A script is meant to copy every log file that isn’t empty from /var/log into /backup. Its six lines were pasted into a ticket in the wrong order.
Arrange the lines so the script works.
The first line names the interpreter. The for loop takes each file matching /var/log/*.log in turn, and do opens its body. Inside it, if tests the file with -s, which is true when the file exists and isn’t empty, and then opens the block that runs when the test passes. The copy goes inside that block. fi closes the if, and done closes the loop: blocks close in the reverse of the order they opened.
Question 6 · Matching · Troubleshooting
A web server is misbehaving and you have a shell on it. Each question you need answered has one command that answers it directly.
Match each question to the command you would run.
df -h shows how full each filesystem is, and du -sh sizes the directories inside one. top lists processes by CPU use, live. journalctl -u shows one service’s log, which is where its startup error will be. ss -tulpn lists listening ports with the process behind each, and dmesg prints the kernel’s messages, including hardware errors. lsblk lists disks and partitions, and free -h shows memory.
CompTIA lists Linux+ among its certifications with simulation performance-based questions: tasks in an approximation of a real tool, such as a firewall, a network diagram or a terminal window. CompTIA’s page on performance-based questions, read on November 12, 2026.
Guide
CompTIA describes performance-based questions as exam items that test your ability to solve problems in real-world settings. Most are simulations: an approximation of a tool such as a firewall, a network diagram, a terminal window or an operating system.
You don’t pick an answer. You do the task, and there can be more than one correct way to do it.
Try each question cold. Getting it wrong first and then reading why teaches more than reading the answer and nodding along.
A right answer reached by guessing is a wrong answer waiting for exam day. Every question here explains why each part is what it is.
CompTIA says a simulation question can be skipped and returned to later, with your work saved. If one is eating your time, move on, answer the multiple-choice questions and come back.
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Open the toolFAQs
Find quick answers or contact our support team.
Yes. CompTIA lists Linux+ among its certifications with simulation performance-based questions: tasks in an approximation of a real tool, such as a firewall, a network diagram or a terminal window. That is from CompTIA’s page on performance-based questions, read on November 12, 2026.
No. They’re original tasks written to each exam’s published objectives. Using leaked real exam questions breaks every vendor’s exam rules.
CompTIA says a performance-based question can have more than one correct way through it, that its scoring allows for the different approaches, and that partial credit may be given. Here, each question is scored by its parts, so you can see which part you missed.
CompTIA says a simulation question can be skipped and returned to later, and that your work on it is saved when you move on. A virtual-environment question has to be completed when you reach it: a warning screen tells you so first.
No. It’s a practice terminal that runs in your browser. It understands the real commands the task needs and answers the way the real system would, but it isn’t a full operating system: nothing is installed, and nothing you type can break anything.
No. The questions run in your browser and nothing is saved. Sign up only if you want full practice exams and progress tracking.
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