The Desktop Environment#

Concepts#

What Is a Desktop Environment?#

A desktop environment (DE) is the graphical interface that lets you interact with Linux using a mouse, windows, icons, and menus — similar to what you are used to on Windows or macOS. Unlike those systems, Linux lets you choose your desktop environment. The most common ones are:

Desktop Environment Style Resource Usage Used By Default In
GNOME Modern, minimal, activity-based Medium-high Ubuntu, Debian (default option), Fedora
KDE Plasma Feature-rich, Windows-like Medium Kubuntu, KDE Neon, Fedora KDE
XFCE Lightweight, traditional Low Xubuntu, MX Linux
Cinnamon Traditional, Windows-like Medium Linux Mint

Both Ubuntu 24.04 and Debian 12 use GNOME as the default desktop. Ubuntu ships a slightly customized version (orange theme, a dock on the left side). Debian ships a more “vanilla” GNOME.

This lesson covers GNOME, since that is what you will see after a fresh install of either distro.

The GNOME Desktop — Key Components#

When you log in, you see the desktop. Here is what is on screen:

  1. Top Bar — Spans the full width at the top.

    • Activities button (top-left corner) — opens the Activities Overview.
    • Clock and calendar (center) — click to see a calendar and notifications.
    • System menu (top-right) — Wi-Fi, Bluetooth, volume, power, settings, lock, log out.

  2. Activities Overview — Press the Super key (Windows key) or click “Activities” to open it.

    • Search — Start typing to search for applications, files, and settings.
    • Application grid — Click the grid icon (bottom of the dash) to see all installed applications.
    • Workspaces — Virtual desktops shown on the right side. You can drag windows between them.

  3. Dash / Dock — A strip of favorite application icons.

    • Ubuntu: A dock on the left side, always visible by default.
    • Debian: The dash only appears in the Activities Overview (unless you install an extension).

  4. File Manager — Called Nautilus (or “Files”). Works like Windows Explorer or macOS Finder.

  5. Settings — Accessed from the system menu (top-right gear icon) or by searching “Settings.”

Essential Keyboard Shortcuts#

Shortcut Action
Super Open Activities Overview / search
Super + A Show all applications
Alt + Tab Switch between open applications
Super + Arrow Left/Right Snap window to left/right half of screen
Super + Arrow Up Maximize window
Super + Arrow Down Restore/minimize window
Ctrl + Alt + T Open a terminal (Ubuntu default)
Super + L Lock the screen
Super + D Show desktop (minimize all windows)

Debian note: Ctrl + Alt + T may not open a terminal by default on Debian’s GNOME. You can set it up in Settings → Keyboard → Keyboard Shortcuts → Custom Shortcuts, or open a terminal from the Activities Overview by searching “Terminal.”

File Manager Basics#

The Files application (Nautilus) provides a graphical way to browse your files:

  • Home folder — Your personal directory (/home/yourusername/). This is where your documents, downloads, and configuration files live.
  • Sidebar — Quick access to Home, Desktop, Documents, Downloads, Music, Pictures, Videos, Trash, and mounted drives.
  • Hidden files — Files and folders starting with . are hidden by default. Press Ctrl + H to toggle visibility.
  • Path bar — Click the breadcrumb path at the top to navigate. Press Ctrl + L to type a path directly.

Installing Additional Software (GUI)#

Both Ubuntu and Debian provide a graphical software center:

  • Ubuntu: “Ubuntu Software” (actually the Snap Store, backed by snap)
  • Debian: “GNOME Software” (backed by apt and optionally Flatpak)

You can browse categories, search for applications, and install them with a click. Behind the scenes, these tools use the same package managers you will learn to use from the command line in Module 04.

Lab#

Exercise 1: Explore the Desktop#

  1. Log into your Ubuntu or Debian VM.
  2. Press the Super key to open the Activities Overview.
  3. Type “Files” and press Enter to open the file manager.
  4. Navigate to your Home folder. Note the standard folders: Desktop, Documents, Downloads, Music, Pictures, Videos.
  5. Press Ctrl + H to show hidden files. You should see files like .bashrc, .profile, and folders like .config/. Press Ctrl + H again to hide them.

Exercise 2: Workspaces#

  1. Press Super to open Activities.
  2. On the right side, you should see your current workspace and an empty workspace below it.
  3. Open the file manager on workspace 1.
  4. Drag it to workspace 2 in the overview, or press Super + Shift + Page Down to move the current window to the next workspace.
  5. Click workspace 1 (now empty) and open a different application (e.g., search for “Text Editor”).
  6. Use Super + Page Up / Super + Page Down to switch between workspaces.

Exercise 3: Window Snapping#

  1. Open the file manager.
  2. Press Super + Left Arrow — the window snaps to the left half of the screen.
  3. Press Super + Right Arrow — it snaps to the right half.
  4. Press Super + Up Arrow — it maximizes.
  5. Press Super + Down Arrow — it restores to the original size.

Exercise 4: Open a Terminal#

  1. Press Ctrl + Alt + T (Ubuntu) or press Super, type “Terminal”, and press Enter (both distros).
  2. A terminal window opens. You will spend most of this course here.
  3. Type echo "Hello, Linux!" and press Enter. The text appears below.
  4. Type exit and press Enter to close the terminal.

Exercise 5: Change a Setting#

  1. Open Settings (click the system menu in the top-right → gear icon, or search “Settings”).
  2. Go to Appearance:
    • Ubuntu: Try switching between Light and Dark style.
    • Debian: Try changing the background wallpaper.
  3. Go to Displays and check your screen resolution. If using VirtualBox with Guest Additions, try resizing the VM window — the resolution should adapt automatically.

Review#

1. What is a desktop environment, and how does it differ from the Linux kernel?

A desktop environment is the graphical interface (windows, menus, icons) that lets you interact with the system visually. The kernel manages hardware resources underneath. The DE is an application that runs on top of the kernel and other system software.

2. What desktop environment do both Ubuntu 24.04 and Debian 12 use by default?

GNOME. Ubuntu ships a customized version with a visible dock, while Debian ships a more standard (“vanilla”) GNOME.

3. How do you open the Activities Overview?

Press the Super key (Windows key), or click “Activities” in the top-left corner of the screen.

4. What keyboard shortcut opens a terminal on Ubuntu?

Ctrl + Alt + T. On Debian, this may not be configured by default — you can open a terminal by pressing Super, typing “Terminal”, and pressing Enter.

5. How do you show hidden files in the GNOME file manager?

Press Ctrl + H. Hidden files and folders are those whose names start with a dot (.).

6. What is the difference between the software center on Ubuntu and Debian?

Ubuntu’s “Ubuntu Software” is primarily the Snap Store (uses snap). Debian’s “GNOME Software” is backed by apt (and optionally Flatpak). Both provide a graphical way to install applications.

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