The Filesystem Hierarchy Standard (FHS) constitutes the structured backbone of Linux system organization, serving as a guideline for directory layout and file placement. For CompTIA Linux+ candidates, mastering the FHS is essential for effective system management as it ensures consistency and interoperability across different Linux distributions. By standardizing locations, the FHS allows administrators to predictably locate binaries, configuration files, and logs, regardless of whether they are managing a Debian, Red Hat, or Ubuntu system.

The hierarchy originates at the root (`/`) directory. Essential command binaries required for all users reside in `/bin`, while system administration binaries largely used by the root user are located in `/sbin`. The `/etc` directory is the critical hub for host-specific, system-wide configuration files. User data is strictly segregated: standard user home directories are found in `/home`, while the superuser's home is `/root`.

Variable data, which changes as the system runs, is managed within `/var`. This includes log files (`/var/log`), mail spools, and databases, making it a primary target for troubleshooting. Conversely, `/usr` (User System Resources) typically holds read-only, shareable data like installed applications and libraries. The `/boot` directory contains crucial files for the boot process, such as the kernel and bootloader config. Additionally, Linux interacts with hardware via files in `/dev`, and exposes kernel information through virtual filesystems like `/proc` and `/sys`. Understanding these standard locations is vital for partitioning disks, securing the system, and writing portable automation scripts.

The Linux boot process initializes hardware and loads the OS through four distinct stages: BIOS/UEFI, Bootloader, Kernel, and Init. Initially, the **BIOS/UEFI** runs the Power-On Self-Test (POST) and executes the bootloader found on the boot sector. The **Bootloader** (commonly **GRUB2**) lets the user select an OS and loads the Linux **Kernel** and initramfs into memory. The Kernel initializes hardware drivers, mounts the root filesystem, and executes the initial process, assigned Process ID (PID) 1.

In modern Linux systems, PID 1 is **systemd**. Systemd is a system and service manager that bootstraps the user space. Unlike the older SysVinit, which loaded scripts sequentially, systemd starts services in parallel, significantly reducing boot times. It manages resources via **Units** (config files ending in .service, .mount, etc.).

Systemd organizes system states using **Targets**, replacing the concept of numerical runlevels. For instance, `multi-user.target` equates to a generic multi-user text mode (legacy Runlevel 3), while `graphical.target` includes the display manager (legacy Runlevel 5). Administrators manage this system primarily using the `systemctl` command to start, stop, enable, or mask services, and `systemd-analyze` to troubleshoot boot performance. Mastery of systemd dependencies and unit files is a core requirement for CompTIA Linux+.

In the context of CompTIA Linux+, storage management is a critical domain focusing on organizing physical disks into usable file systems. Administrators typically utilize two methods: traditional partitioning and Logical Volume Manager (LVM).

Traditional partitioning involves dividing a physical disk into distinct sections using partition tables like Master Boot Record (MBR) or GUID Partition Table (GPT). MBR is a legacy standard limited to 2 TB drives and four primary partitions, while GPT is the modern standard associated with UEFI, supporting zettabytes of data and up to 128 partitions. Tools such as `fdisk`, `gdisk`, and `parted` are used to manage these structures. However, traditional partitions are rigid; resizing them usually requires unmounting and can be risky.

LVM offers a more flexible alternative by abstracting physical storage. The LVM architecture consists of three layers: Physical Volumes (PVs), which are the actual disks or partitions; Volume Groups (VGs), which aggregate multiple PVs into a single storage pool; and Logical Volumes (LVs), which are carved out of the VG and act like partitions. The primary benefit of LVM is elasticity. Administrators can resize Logical Volumes dynamically (e.g., using `lvextend`) and expand filesystems on the fly without system downtime. Additionally, new physical disks can be added to a Volume Group to increase total capacity seamlessly.

Once storage is defined via partitions or LVM, it must be formatted with a filesystem (such as ext4 or XFS) using `mkfs`, and then mounted to a directory point. Persistent mounting is managed via the `/etc/fstab` file. Mastery of these concepts, along with troubleshooting commands like `lsblk`, `df`, and `blkid`, is essential for passing the Linux+ exam.

In the context of CompTIA Linux+ system management, package management is the organized method of installing, updating, querying, and removing software. It ensures system stability by managing dependencies—libraries required by applications to function. There are two primary package management ecosystems you must master: RPM and DEB.

**RPM (Red Hat Package Manager)** is used by distributions like RHEL, Fedora, CentOS, and openSUSE. It utilizes `.rpm` files.
* **Low-Level:** The `rpm` command installs or queries local files but does not resolve dependencies automatically.
* **High-Level:** Tools like `dnf` (Dandified YUM), `yum` (legacy), and `zypper` (SUSE) act as front-ends. They connect to repositories, download necessary metadata, and automatically install the software alongside all required dependencies.

**DEB (Debian)** is used by distributions like Debian, Ubuntu, and Linux Mint. It utilizes `.deb` files.
* **Low-Level:** The `dpkg` command manages local `.deb` files. Like `rpm`, it cannot download dependencies from the internet.
* **High-Level:** The Advanced Package Tool suite, utilizing commands like `apt` or `apt-get`, handles repository logic. Running `apt install [package]` resolves complex dependency trees and manages upgrades seamlessly.

For the exam, it is crucial to distinguish between low-level tools (used for specific file installs or verification) and high-level tools (used for general management/updates), and to know which distributions utilize which format.

In the context of CompTIA Linux+, networking configuration is a fundamental domain requiring the ability to manage interfaces, IP addressing, routing, and hostname resolution using both command-line utilities and configuration files. Administrators must distinguish between temporary runtime changes and persistent settings.

Modern Linux distributions have largely shifted from the legacy `net-tools` package (which included `ifconfig` and `netstat`) to the `iproute2` suite. Consequently, the `ip` command is the primary tool for assigning addresses (`ip addr`) and managing routes (`ip route`), while `ss` is used to investigate sockets and open ports. For persistent configuration, **NetworkManager** is the prevailing service, managed via the `nmcli` command or the `nmtui` text interface.

Configuration files vary by distribution family. Debian and Ubuntu systems often utilize **Netplan**, which reads YAML files located in `/etc/netplan/` to generate backend configurations. Red Hat enterprise systems historically used scripts in `/etc/sysconfig/network-scripts/`, though they also rely heavily on NetworkManager today.

Name resolution is handled locally via the `/etc/hosts` file and globally through DNS servers defined in `/etc/resolv.conf`. Because modern systems often use `systemd-resolved`, the `resolv.conf` file is frequently a symlink, and DNS settings should be managed via tools like `resolvectl` or `nmcli` rather than editing the file directly. The order in which the system queries these sources (local files vs. DNS) is determined by `/etc/nsswitch.conf`. Proficiency in these areas, along with troubleshooting tools like `ping`, `mtr`, and `dig`, is essential for system stability and exam success.