System Management
System management is the largest domain of the XK0-006 exam and covers how a Linux system is organized, installed, and maintained day to day. You will need fluency with the filesystem hierarchy, package managers, systemd, and storage. Mastery here underpins nearly every other task an administrator performs.
Filesystem Hierarchy Standard
The FHS defines a predictable directory layout so administrators know where files belong regardless of distribution. Configuration lives in /etc, variable data such as logs and spools in /var, user programs in /usr, and optional third-party software in /opt. Runtime pseudo-filesystems like /proc and /sys expose kernel and process information. Understanding this map lets you locate configuration and logs quickly during administration and troubleshooting.
Package Management
Debian-based systems use apt with dpkg underneath, while Red Hat-based systems use dnf with rpm underneath. Use 'apt update' then 'apt upgrade' to refresh indexes and install updates, or 'dnf install' and 'dnf update' on RHEL-family hosts. Low-level tools like 'dpkg -i' and 'rpm -q' install or query individual packages without resolving dependencies. Repositories are configured under /etc/apt or /etc/yum.repos.d and can be enabled, disabled, or pinned.
systemd and systemctl
systemd is the default init and service manager on modern distributions, controlling units such as services, sockets, mounts, and timers. Use 'systemctl start', 'stop', 'enable', and 'disable' to control runtime and boot behavior, and 'systemctl status' to inspect a unit. Targets replace the older runlevels, with multi-user.target and graphical.target being common. Unit files live in /etc/systemd/system for local overrides and /usr/lib/systemd/system for packaged defaults.
Storage and Filesystems
Block devices are inspected with 'lsblk' and 'blkid', partitioned with tools like fdisk or parted, and formatted with mkfs. Persistent mounts are declared in /etc/fstab using UUIDs, mount options, and an fsck pass order. LVM adds flexibility by layering physical volumes, volume groups, and logical volumes that can be resized online. Knowing how to mount, unmount, and grow storage is essential for capacity management.
System Monitoring and Time
Administrators keep systems healthy by watching resource usage and keeping clocks synchronized. Tools like 'df', 'du', 'free', and 'uptime' summarize disk, memory, and load. Time synchronization is typically handled by chronyd or systemd-timesyncd and verified with 'timedatectl'. Consistent time is critical for logging, authentication protocols, and scheduled jobs.