XK0-006 cheat sheet

Exam at a glance

Domain weightings

How much of the exam each domain covers. Spend your study time in proportion — the heavier the domain, the more questions you'll see.

Key terms

systemd

systemd is the init system and service manager used by most modern Linux distributions, managing units, targets, and boot. Linux+ covers systemd units, services, and targets under system management.

systemctl

systemctl is the command-line tool used to control and inspect systemd services and units (start, stop, enable, status). Linux+ requires managing services with systemctl.

journalctl

journalctl is the command that queries and displays logs collected by the systemd journal. Linux+ covers using journalctl to investigate service and boot issues during troubleshooting.

LVM

LVM (Logical Volume Manager) abstracts physical disks into flexible logical volumes that can be resized and snapshotted. Linux+ covers LVM within storage management.

Filesystem

A filesystem organizes how data is stored and retrieved on a device; common Linux filesystems include ext4, XFS, and Btrfs. Linux+ covers creating, mounting, and troubleshooting filesystems.

Mount

Mounting attaches a filesystem to a directory in the Linux directory tree, configured at runtime or persistently in /etc/fstab. Linux+ covers mounts and quotas under storage management.

SELinux

SELinux (Security-Enhanced Linux) is a mandatory access control system that confines processes with security policies and contexts. Linux+ covers SELinux (and AppArmor) for hardening under the Security domain.

AppArmor

AppArmor is a mandatory access control framework that restricts programs using per-application profiles. Linux+ covers it alongside SELinux for access control and hardening.

PAM

PAM (Pluggable Authentication Modules) is the framework that handles authentication for Linux services through configurable modules. Linux+ covers PAM within authentication and identity.

SSH

SSH (Secure Shell) is the encrypted protocol for remote login and command execution, commonly authenticated with keys. Linux+ covers configuring and securing SSH for remote access.

LUKS

LUKS (Linux Unified Key Setup) is the standard for full-disk encryption on Linux. Linux+ covers LUKS for encrypting storage under the Security domain.

GPG

GPG (GNU Privacy Guard) provides encryption and digital signatures using public-key cryptography. Linux+ covers GPG for file encryption and signing.

firewalld

firewalld is a dynamic firewall manager for Linux that uses zones and services as a front end to nftables. Linux+ covers firewalld and nftables for network security.

nftables

nftables is the modern Linux kernel packet-filtering framework that replaces iptables. Linux+ covers nftables (often via firewalld) for firewall configuration.

Ansible

Ansible is an agentless configuration-management and automation tool that applies desired state through playbooks. Linux+ covers Ansible concepts under automation, orchestration, and scripting.

Bash

Bash is the default shell and scripting language on most Linux systems, used to automate tasks with variables, conditionals, and loops. Linux+ requires writing and troubleshooting Bash scripts.