Documentation

This is the documentation section of Ubuntu Portal, where we keep the reference material you’ll reach for over and over: command-line essentials, filesystem configuration, package management deep-dives, and the system administration fundamentals that underpin everything else you do on Ubuntu. These aren’t quickstart stubs — each page is written with the kind of detail that comes from actually running these commands on production systems, debugging the edge cases, and knowing which defaults are safe to change and which ones will ruin your afternoon. If you’re looking for longer task-based walkthroughs, our Step-by-Step Guides section is the better fit; what you’ll find here is the foundational knowledge those guides assume you have.

What’s in the Docs Section

We’ve organized documentation around the tasks Ubuntu administrators and power users actually perform. Not alphabetical API listings or man-page mirrors — structured, opinionated references that tell you what to do, why it works, and what to watch out for.

CLI Basics: apt, dpkg, and Package Management

If there’s one skill that separates a casual Ubuntu user from someone who actually understands their system, it’s package management. This page covers apt update, apt upgrade, apt full-upgrade, and when to use each one. It digs into dpkg for when apt isn’t enough — forcefully removing a broken package, querying which package owns a file, extracting a .deb without installing it. We also cover the apt vs apt-get distinction (spoiler: apt is the one you want for interactive use, but scripts should still use apt-get), package pinning with /etc/apt/preferences.d/, and the nala frontend that’s been gaining traction as a more readable alternative to raw apt output.

Practical knowledge here includes:

• Cleaning the package cache when /var/cache/apt/archives/ eats your disk
• Holding packages at a specific version when an upstream update breaks your workflow
• Understanding the difference between apt remove and apt purge (hint: config files)
• Recovering from a broken dpkg lock when a previous operation crashed

This is the page to start with if you’re new to the terminal, and the page to revisit when something goes wrong with your packages.

Filesystems and Mounts: fstab, UUID, and Recovery

Every Ubuntu system boots by reading /etc/fstab, and a surprising number of boot failures trace back to a mistake in that file. This page covers the fstab format line by line — device identifier, mount point, filesystem type, options, dump flag, pass number — and explains why UUID= is almost always better than /dev/sdXN for identifying devices. (Short version: device names can shift between boots; UUIDs don’t.)

Beyond the basics, we cover:

• Common mount options for ext4, NTFS (via ntfs-3g), and Btrfs
• The noatime vs relatime decision and when it actually matters for performance
• Automounting network shares with cifs and nfs entries in fstab
• What happens when an fstab entry fails at boot (emergency mode) and how to recover
• Using systemd mount units as a modern alternative to raw fstab entries
• findmnt, lsblk, and blkid — the trio of tools you need for diagnosing mount issues

If you’ve ever stared at a blinking cursor during boot because you mistyped a UUID, this page will make sure it doesn’t happen twice.

How These Docs Are Structured

Every documentation page on Ubuntu Portal follows a consistent format:

1. Overview — What the topic is, why it matters, and which Ubuntu versions are covered.
2. Core concepts — The foundational knowledge: config file formats, key commands, important defaults.
3. Practical examples — Real commands you can copy and run, with explanations of every flag.
4. Common pitfalls — The mistakes we’ve made (or watched others make) and how to avoid them.
5. Troubleshooting — When things go wrong: symptoms, diagnostic steps, fixes.
6. Related reading — Internal links to other Ubuntu Portal pages that cover adjacent topics.

We don’t pad pages with obvious filler. If a section would just restate the man page, we skip it and point you to the relevant man page instead. The goal is to add the context and judgment that man pages — by design — don’t provide.

Who This Section Is For

Honestly? Everyone who uses Ubuntu beyond clicking icons. Whether you’re a developer who needs to understand why your Docker containers can’t write to a mounted volume, a sysadmin managing a fleet of Ubuntu servers, or a hobbyist who just wants to understand what’s happening when you type sudo apt install something — the docs section is where that understanding lives.

You don’t need to be a Linux veteran to follow along. We explain jargon when it first appears, and we include the exact commands to run — not just the concept, but the bash you’d paste into a terminal. That said, we don’t dumb things down either. If a topic requires understanding file permissions or process management, we’ll say so and link to the relevant page.

Relationship to Other Sections

The docs section is the reference layer of Ubuntu Portal. Here’s how it fits with the rest:

• Guides are task-oriented — “How to install Xfce 4.18 on Ubuntu 24.04.” They link back to docs pages when you need to understand a concept the guide uses.
• Hardware covers device-specific topics — GPU drivers, printers, scanners. Those pages reference docs concepts like kernel modules and dkms.
• Releases covers version history and upgrade guidance. When a release changes a default (like the switch from X11 to Wayland), the docs section explains the implications.
• Tools covers individual applications and utilities. Some tools have configuration that ties back to system concepts covered here.

Think of it as a dependency graph: most other sections on Ubuntu Portal depend on the docs section, but the docs section stands on its own.

Coming Up

We’re actively expanding the documentation section. Topics in progress include:

• Networking fundamentals — Netplan configuration, systemd-networkd vs NetworkManager, firewall basics with ufw
• User and permission management — adduser, usermod, groups, sudoers, file ownership
• Systemd essentials — Services, timers, targets, and journalctl deep-dive
• Kernel management — Installing, switching, and removing kernels; understanding dkms

Each of these will follow the same structure and depth as our existing pages. If you’re waiting for a specific topic, check back — or browse the home page for recently updated content.

Start Reading

The best way to use this section is to jump straight to the topic you need:

• Package management? → CLI Basics
• Disk and mount configuration? → Filesystems and Mounts

Both pages are written to be useful whether you read them front to back or search for a specific command. And if you find yourself in a bind — staring at a broken boot, a locked dpkg database, or a mount that refuses to stick — the troubleshooting sections are there for exactly that moment.