1.3 Installing Linux

Understanding the Installation Process

Before touching any settings, it helps to know the basic steps that almost all Linux installations follow:

1. Get an installation image
   A distribution provides an .iso file (disc image) you download from its website.
2. Verify the download (optional but recommended)
   You compare checksums (like sha256sum) or signatures to ensure the file isn’t corrupted or tampered with.
3. Write the image to installation media
   Usually a USB stick, sometimes a DVD. This makes it bootable.
4. Boot from the installation media
   You tell your computer to start from the USB instead of the internal drive.
5. Run the installer
   The installer asks questions (language, keyboard, partitions, user account, etc.).
6. Install the system
   Files are copied to your disk and the bootloader (usually GRUB) is installed.
7. Reboot into your new system
   Remove the USB, reboot, and log into Linux.

Each subchapter (bootable USB, dual boot, virtual machine, partitioning, etc.) will go deeper into its part of this flow. Here we’ll focus on preparation, common decisions, and the overall structure so you know what to expect.

Choosing an Installation Method

There are three common ways new users install Linux:

1. On real hardware only
   Linux becomes the main OS on your machine.
• Pros: Best performance, uses full hardware, no extra layer.
• Cons: Requires wiping or shrinking existing OS; risk if you mis-partition.
2. Dual boot with another OS (often Windows)
   Linux and Windows share the same machine; you choose at startup.
• Pros: Keep Windows, try Linux natively.
• Cons: Partitioning is more complex; bootloader issues can occur.
3. In a virtual machine (VM)
   Linux runs as a guest system inside your existing OS (using tools like VirtualBox, VMware, etc.).
• Pros: Safest way to experiment; no disk changes; easy to delete and start over.
• Cons: Slower than native; needs more RAM and CPU from the host.

For absolute beginners, a virtual machine is often the least risky way to learn. When you feel comfortable, you can install on real hardware or set up a dual boot.

Preparing for Installation

Hardware Requirements

Each distribution gives recommended specs, but baseline guidance:

• CPU: Any 64-bit processor from roughly the last 10–15 years is usually fine.
• RAM:
• 2 GB: Light desktop environments only (may feel slow).
• 4 GB: Usable for most beginner desktops.
• 8 GB+: Smooth experience, especially in VMs or heavier desktops.
• Disk space:
• Minimum: 15–20 GB just for the system.
• Comfortable: 40+ GB if you want apps, media, and updates.
• GPU: Integrated graphics are usually enough; very new or very old GPUs might need extra driver work.
• Network: Wired Ethernet is simplest; Wi-Fi normally works but may need proprietary firmware on some hardware.

In a VM, you choose how much RAM and disk to allocate. Don’t assign more RAM than your host can spare.

Back Up Your Data

If you’re installing on real hardware or dual booting, back up important files first:

• Documents, photos, projects, browser data, etc.
• Store backups on an external drive or cloud storage.

Even if the installer offers safe options, a misclick in partitioning can erase entire drives.

Downloading the Installation Image

1. Go to the distribution’s official website.
   Avoid third-party mirrors until you know what you’re doing.
2. Choose the correct architecture.
   For almost everyone on a modern PC or laptop, this is x86_64 or called “64-bit” / “amd64”.
3. Choose the edition/flavor.
   Some distributions ship multiple editions (e.g., different desktop environments). Pick the default or “recommended for beginners” option if unsure.
4. Download the ISO file.
   This is usually several GB in size.

(Optional) Verifying the ISO

Distributions usually provide a checksum file and sometimes GPG signatures. The general pattern is:

• Download:
• The ISO file (e.g. ubuntu-24.04-desktop-amd64.iso)
• The checksum file (e.g. SHA256SUMS)
• On a Linux or macOS system, run something like:

sha256sum ubuntu-24.04-desktop-amd64.iso
cat SHA256SUMS

Compare the checksum output with the value in SHA256SUMS. If they match exactly, your ISO is intact.

If you’re on Windows and don’t want to learn checksum tools yet, you can skip this, but understand there is a small risk of a corrupted download.

Understanding “Live” Installers

Many desktop distributions provide a live environment:

• You boot from the USB and get a fully functional Linux desktop.
• You can try applications, test hardware (Wi-Fi, sound, graphics).
• There is usually an icon like “Install [Distribution]” on the desktop.

This lets you test whether Linux works well on your hardware before modifying your disk. Performance from USB will be slower than a real install, but basic functionality should be visible.

Some installers are text-based or non-live: you go straight into an installation interface without a full desktop environment. The steps are conceptually the same but with fewer visual previews.

Typical Installer Questions and Choices

While the layout varies by distribution, most installers ask similar questions. Here’s what they usually mean and what’s safe for beginners.

Language, Keyboard, and Time Zone

• Language: Affects menus and system messages. You can often add more languages later.
• Keyboard layout: Select the layout that matches your physical keyboard (e.g. US, UK, German, etc.).
• Time zone: Used for the system clock and timestamps. Often selected by clicking on a world map.

These choices are straightforward and easy to change later.

Installation Type

You’ll often see options like:

• Erase disk and install [Distribution]:
  Uses the entire disk for Linux. This deletes all existing data on that disk. Good for:
• Old computers you repurpose for Linux.
• Machines where you no longer need Windows or any previous OS.
• Install alongside [Existing OS]:
  Sets up a dual boot automatically:
• Resizes existing partitions for you.
• Adds Linux next to Windows or another OS.
• Creates a boot menu so you can choose at startup.
  This is the easiest dual-boot option if it appears.
• Something else / Manual partitioning / Custom:
  Lets you manually partition the disk.
  This is powerful but dangerous if you don’t understand partitions. Detailed partitioning is covered separately; for now, know that:
• Use this only when you have a specific plan.
• Always double-check which disk and partitions you are editing.

Choosing the right option depends on whether you want to keep your existing OS and data, which is covered more deeply in the dual-boot chapter.

Disk and Partition Selection

If you have multiple physical drives (e.g. SSD and HDD), the installer will list them, often as:

• /dev/sda, /dev/sdb, etc. (names will vary)
• Alongside sizes (e.g. 512 GB, 1 TB) and sometimes vendor names.

Basic guidance:

• Make sure you recognize which is which using capacity and description.
• If you choose “erase disk,” confirm you’re erasing the intended drive.
• For dual boot, you will usually pick the disk that already holds your existing OS.

Details about the specific partitions (/, /home, Swap) will be handled in the partitioning chapter. Many installers have an “automatic” partitioning option that is safe for beginners when using an entire disk.

Creating Your User Account

Installers usually ask for:

• Your name
• Computer name / hostname (e.g. alice-laptop)
• Username (e.g. alice)
• Password (and possibly whether to log in automatically)

Tips:

• Choose a strong password: at least 10–12 characters, mix words and symbols if possible.
• Avoid enabling automatic login on laptops or shared machines (it reduces security).
• Hostname can be simple and descriptive; it can be changed later.

This user will usually be added to the sudo group so you can perform administrative tasks using sudo.

Bootloader Installation

Most installers automatically install GRUB (or a similar bootloader) to your primary drive:

• On a single-boot system (Linux only), it loads Linux directly.
• On a dual-boot system, it presents a menu to choose between Linux and the other OS.

Beginners generally don’t need to change the default bootloader settings. If you see an option like “Install bootloader to /dev/sda,” it’s usually correct to leave it as-is unless you know you have a special layout.

Installing on UEFI vs BIOS Systems (Conceptual)

Modern machines typically use UEFI instead of old-style BIOS:

• UEFI systems often have an EFI System Partition (ESP), a small FAT32 partition that stores bootloaders.
• Many installers detect UEFI and create or reuse the ESP automatically.

You don’t need to manage this manually as a beginner, but be aware:

• If you see an “EFI System Partition” listed, don’t delete it unless you know exactly what you’re doing.
• When dual booting, both Windows and Linux usually share this partition, each with its own bootloader files.

Boot process details and GRUB specifics are handled in later chapters.

Common Installation Pitfalls and How to Avoid Them

1. Installing on the Wrong Disk

Symptom: You meant to install on a secondary drive but wiped your main disk instead.

How to avoid:

• Carefully read disk sizes and model names.
• If your primary disk is 512 GB and a secondary is 1 TB, check that the selected disk matches your expectation.
• When in doubt, disconnect drives you do not want to touch (on desktops) while installing.

2. Overwriting an Existing OS by Accident

Symptom: You choose “erase disk” on a drive that contains Windows or personal data.

How to avoid:

• If you want dual boot, don’t choose “erase disk.” Use “Install alongside” or a manual layout as described in the dual-boot chapter.
• If the installer doesn’t offer “Install alongside” and you’re a beginner, consider installing Linux in a VM instead, or get help before proceeding.

3. Insufficient Disk Space

Symptom: Installer refuses to continue or system runs out of space quickly.

How to avoid:

• Ensure you allocate at least 15–20 GB; 40+ GB is safer for desktop use.
• In a VM, if you’re unsure, a 40–60 GB virtual disk is often a good starting point.

4. Boot Order Issues After Installation

Symptom: After installing, the machine boots straight into the old OS or doesn’t start Linux.

General guidelines:

• Enter firmware settings (BIOS/UEFI) and check the boot order; ensure your Linux entry or drive is at the top.
• If an OS is missing from the boot menu, it often can be restored without reinstalling Linux (boot troubleshooting is handled later in the course).

5. Network/Wi‑Fi Not Working During Install

Symptom: Installer can’t connect to the internet.

Notes:

• Many installers can proceed without internet; they simply won’t download updates or extra drivers during install.
• You can often install drivers and updates afterward.
• If a wired connection is available, use Ethernet during installation; it’s more reliable than Wi‑Fi.

What Happens During the Actual Installation

Once you click “Install” or “Continue” after all questions:

1. The installer:
• Formats the selected partitions.
• Copies the system files to your chosen root filesystem.
• Writes bootloader entries.
• Creates your user and sets initial system configuration.
2. Progress bars:
• The process may take from a few minutes to around half an hour, depending on hardware speed and whether updates are downloaded.
3. When done:
• You’re typically asked to restart.
• Remove the USB/DVD when prompted, so the system boots from the hard drive.

First Boot Checklist

On first boot into your new Linux system:

1. Log in with the user/password you created.
2. Confirm basic hardware:
• Keyboard and mouse/trackpad.
• Display resolution (should fill the screen).
• Sound output (play a test sound if possible).
• Network (wired or Wi‑Fi).
3. Run system updates using either:
• The graphical software updater, or
• The appropriate command-line tools (covered later in the “Updating the system” and package management chapters).

If a piece of hardware doesn’t work correctly, don’t panic: driver setup and troubleshooting are addressed in later chapters.

When to Reinstall vs. When to Fix

As a beginner, it’s important to know that:

• If you severely misconfigure something very early on (for example, you pick strange partition layouts, or the system fails to boot and you’re completely lost), reinstalling is often faster than deep troubleshooting.
• As long as your personal data is backed up (or stored on a separate partition), reinstalling is usually low risk.

Later in the course, you’ll learn more about repairing bootloaders, adjusting partitioning, and other advanced fixes, so reinstalling will become less necessary.

Summary

Installing Linux is mostly about:

• Preparing carefully (backups, downloading the right ISO).
• Choosing an installation method that fits your risk tolerance (VM, single boot, dual boot).
• Making informed choices at key steps: which disk to use, whether to erase or share it, and how to set up your user.
• Letting the installer handle technical details like filesystems and bootloaders in beginner-friendly modes.

With this overview, you should recognize each major decision the installer presents and know where later chapters will give you the deeper details (USB creation, partitions, dual boot, and virtual machines).