CompTIA Linux+ (XK0-006) Practice Questions & Study Guide
Linux system administration certification covering system management, services, security, automation and scripting, and troubleshooting across major distributions.
What's included
Every Linux+ question includes a worked explanation and hints. Question formats mirror the real exam: multiple choice, multiple select, short answer and drag-and-drop matching. A full timed final exam reports per-domain analytics so you know exactly where you stand before test day.
A sample Linux+ lesson
Linux Boot Process and Bootloaders: GRUB2, systemd-boot, UEFI vs BIOS
The Linux boot process moves through firmware initialization, bootloader execution, kernel loading, and init-system startup in a defined sequence. Understanding each stage—and the differences between BIOS/MBR and UEFI/GPT boot paths—is essential for diagnosing boot failures, configuring dual-boot systems, and hardening bootloader access.
Firmware stage: BIOS vs UEFI
When a system powers on, control passes first to firmware stored on the motherboard. Traditional BIOS (Basic Input/Output System) performs a Power-On Self Test (POST) that checks CPU, RAM, and essential peripherals, then reads the first 512 bytes of the configured boot disk—the Master Boot Record (MBR). The MBR contains a first-stage bootloader (446 bytes), a partition table (64 bytes, supporting up to four primary partitions with a maximum disk size of 2 TB), and a two-byte boot signature. UEFI (Unified Extensible Firmware Interface) replaces BIOS on modern hardware: it reads a dedicated EFI System Partition (ESP), formatted as FAT32 and typically between 100 MB and 1 GB, and can load EFI applications—including full bootloaders—directly by filesystem path without stage-based chainloading. UEFI supports GPT (GUID Partition Table), which allows disks larger than 2 TB and up to 128 partitions on most implementations. A major security feature unique to UEFI is Secure Boot: the firmware maintains a database of allowed cryptographic signatures (db) and a revocation list (dbx); any EFI binary loaded at boot must be signed with a key trusted in db and not revoked in dbx. This prevents unsigned or tampered bootloaders and kernels from executing before the operating system starts. On RHEL and Fedora, shim.efi is the first-stage EFI binary signed by Microsoft; it validates the distribution's own signed GRUB2 EFI binary, enabling Secure Boot compatibility without requiring every distribution key in the firmware.
GRUB2 bootloader
This is one of 50 concept lessons in the full Linux+ track.
Exam facts
- Exam codeXK0-006
- VendorCompTIA
- FormatUp to 90 questions · 90 minutes
- Passing score720 / 900
- Exam cost$369 USD
- Renewal3 years (renew with CEUs)
Pricing
Your first foundational certification is free when you sign up — no card required.
Linux+ FAQ
- How much does the CompTIA Linux+ exam cost?
- The official CompTIA XK0-006 exam voucher is $369 USD. CyberStudy is separate, affordable practice and is not the exam voucher.
- How many questions are on the Linux+ exam?
- The XK0-006 exam is Up to 90 questions · 90 minutes.
- What score do I need to pass Linux+?
- The passing score is 720 / 900.
- How long is Linux+ valid?
- CompTIA Linux+ is valid for 3 years (renew with ceus).
- How much Linux+ practice does CyberStudy include?
- 150 exam-style practice questions across every domain plus a full timed mock exam with analytics, and 50 concept lessons.