Disclaimer: I used my natural language throughout this blog most of it are written at my free time and maybe i have missed some points or i might have blabbered something

So sorry for that in advance :)

Let’s start with the basics why do we need a bootable USB for installing a operating system to a machine?

Computer always boots from some form of storage they look for a bootloader (like GRUB, Windows Boot Manager, etc) to start the OS.

since the system doesn’t have that, we need a external medium a bootable USB in this case that contains a bootable OS installer and a bootloader to kickstart the process.

UEFI is a modern replacement for BIOS, offering a more secure and feature-rich boot process

SO what does a BIOS/UEFI needs

So we give it an external media that contains all of these,

A boot sector is the first sector of a storage device containing instructions to start the computer’s operating system. MBR (Master Boot Record) is a traditional boot sector that holds the bootloader code and a partition table to manage disk partitions, used with older BIOS systems. EFI (Extensible Firmware Interface), now more commonly UEFI (Unified Extensible Firmware Interface), is a modern replacement for BIOS that uses a different boot process, often with a GUID Partition Table (GPT) and an EFI System Partition to manage the boot process.

NOTE: We’re going to learn about the installation process that makes arch users brag (I use Arch BTW). there is another popular way of installation using archinstall script that takes care of some heavy lifting for you.

Few things about Arch

Now you may ask how come archlinux takes only 2 gigs of space?

These OSes thinks our users probably need this so let’s ship it. This makes the base install bloated asf.

Here’s what makes Arch different

Basically bro do whatever you wanna do with your system we don’t make any opinions.

This is one of the reasons people like Arch.

Now let’s move to the steps after plugging in your bootable USB to the target device.

You will be logged in on the first virtual console as the root user, and presented with a Zsh shell prompt.

A virtual console (VC) — also known as a virtual terminal (VT) — is a conceptual combination of the keyboard and display for a computeruser interface. It is a feature of someUnix-likeoperating systemssuch asLinux,BSD,illumos,UnixWare, andmacOSin which thesystem consoleof the computer can be used to switch between multiple virtual consoles to access unrelated user interfaces. Virtual consoles date back at least toXenixandConcurrent CP/Min the 1980s.

Default keyboard layout will be in US other Available layouts can be listed with:

localectl list-keymaps to select a keyboard layout, pass its name to LoadKeys

loadkeys de-latin1 setfont ter-132b This command is to set a big sized font in the terminal in-case if you feel the terminal font is too small to see.

cat /sys/firmware/efi/fw_platform_size This command is to verify the boot mode.

Next set of commands are related to connecting to the internet.

ip link Linux exposes all network interfaces (physical + virtual) through the netlink subsystem.

Netlink is a communication system that lets the kernel and user-space exchange networking information.

It’s like a messaging API built into Linux

kernel can’t read commands like set eth up, netlink is a communication channel between user-space tools (like ip, ifconfig, NetworkManager) and the kernel networking code.

It’s dangerous to let user space programs to change kernel memory

netlink standardizes them it’s literally a socket-based protocol.

It’s the command that asks the kernel for status of all of the network interfaces. ip link is the command that shows and controls network interface on your system.

It’s basically the “interface management” part of the ip command.

if you run this command you’ll see a output sth like

you can also perform certain actions like bringing an interface up and down.

ip link set wlan0 up ip link set eth0 down

rfkill There are bunch of radio transmitters in our system:

Each of these can be soft-blocked(by software) or hard-blocked(by a physical switch or firmware).

rfkill is a debugging + control tool to manage wireless radio devices on Linux.

rfkill list lists all radio devices rfkill unblock all unblocks all radios rfkill unblock wifi unblock only Wi-Fi

connect to wifi using iwctl

ping you know what ping does.

Next up: Changing time and date

timedatectl This command is used to view and change the system date, time, and time-related settings.

it can be achieved by

sudo timedatectl set-time "2025-12-01 21:30:00"sudo timedatectl set-time "2025-12-01"sudo timedatectl set-timezone Asia/Kolkata

Partition the disk

In linux everything is treated as a folder. disks are assigned to a block device such as /dev/sda, /dev/nvme0n1 or /dev/mmcblk0

fdisk -l this command is used to view the disks and partitions alternative popular command for the similar use case would be lsblk

RAID mode shouldn’t be enabled in your system (coz RAID support in linux is poor). If you’re unsure what raid is. take a read at this

https://x.com/kaizakinn/status/1995538976409874904?s=20 Common Example:

sudo fdisk /dev/sda inside fdisk you’ll get options like

as per Arch manual You’ll be told to create a swap partition in this step If you’re unsure what swap is. have a read

https://x.com/kaizakinn/status/1991753444403695900?s=20

Format partitions:

Newly created partitions has to be formatted with an appropriate file system we format ext4 file system on the main partition coz its the default file system for linux.

mkfs.ext4 /dev/root_partition mkfs stands for make file system.

swap partition has to be formatted as well,

mkswap /dev/_swap_partition mkswap stands for make swap.

EFI partition is formatted with FAT32 using

mkfs.fat -F 32 /dev/efi_system_partition

Mounting the file systems:

Mount the root volume to /mnt

/mnt/ ├── boot/ ├── home/ └── (other Linux system files)mount --mkdir /dev/efi_system_partition /mnt/boot mount with --mkdir creates the directory if it doesn't exist.

swapon /dev/swap_partition This command enables the created and formatted swap volume.

Installation

Since arch base install has only essentials additional packages has to be downloaded from the mirror servers.

They are defined in the /etc/pacman.d/mirrorlist The topmost worldwide mirror should be fast enough for most people, if not you can edit the file for the same.

This file will later be copied to the new system by pacstrap, so it is worth getting right.

some essential packages are mentioned in the arch install manual to get you started and its pretty self-explanatory if you read em why you wanna install those packages so im skipping those here.https://wiki.archlinux.org/title/Installation\_guide#Install\_essential\_packages

For example, a basic installation with the Linux kernel and firmware for common hardware:

pacstrap -K /mnt base linux linux-firmware now you may have a question pacman is the package manager in arch right why are we even using pacstrap

When you install Arch from the ISO, you are not inside your actual system yet. You are in a live environment (temporary, RAM-based).

you’re future Arch system lives inside /mnt

You must install the “base system” there. That is exactly what pacstrap does.

pacstrap meaning pac = pacman strap = bootstrap.

pacstrap installs the initial OS files to /mnt

So why is the -K flag at the end?

lemme give you some context before explaining that flag.

Without keys the installed system has no keys so it must initialize them using pacman-key --init

-K avoids these problems.

This is what -K does

Next up: configuring the system

fstab

What is fstab and why do we need it? it is just a config file that tells your system:

Linux has no built-in memory of where your partitions belong. it has no clue where your devices like /dev/sda1/dev/nvme0n1p3/dev/sdb should attach in your folder tree.

Breakdown of fstab entry:

genfstab -U /mnt >> /mnt/etc/fstab genfstab = "Generate fstab entries"

-U means UUIDs "stable, unique identifiers" instead of /dev/sda1 style paths. This is safer because device names can change between boots.

>> this takes the output of genfstab and appends it to /mnt/etc/fstab /mnt is where the arch system currently mounted.

It creates the new Arch system’s /etc/fstab, which tells it:

“Mount these partitions exactly the same way the installer just did, every time the system boots.”

Interactive with the new system’s environment

arch-chroot /mnt What is chroot? as we now know when we install a os to our system we’re booted into a live ISO and that is not our real system. It’s just a temporary environment.

But we need to run commands inside our newly installed system how do we do that even tho the system isn’t booted yet?

that is what chroot = change root is.

now the root folder is changed to the mountpoint /mnt so this creates a fake environment, programs behave like they're running on a live system.

now comes another question. what tf does arch-chroot does? normal chroot only changes the filesystem root. it does not automatically mount:

These dirs provide hardware info, devices, process info, and runtime data. Without these, half the tools will break. Try using pacman inside a plain chroot -> stuff fails. Try installing grub -> fails because no /sys or /dev.

so basically arch-chroot is a wrapper around chroot that handles all these with permissions and environment variables as well.

Time

ln -sf /usr/share/zoneinfo/Area/Location /etc/localtime When your system shows the wrong time, tons of stuff breaks:

Hardcoding your timezone is stupid

Linux uses a file called:

/etc/localtime This file tells Linux “use this TimeZone data”

All timezone definitions are stored in:

/usr/share/zoneinfo/ Inside this folder, you have subfolders like:

Asia/Kolkata Europe/London America/New _York so what does the command do? ln - create a link -s - Symbolic link -f - force overwrite.

It links your timezone info to the /etc/localtime so that your systems behave correctly

hwclock --systohc

To prevent clock drift and ensure accurate time, set uptime synchronizationusing aNetwork Time Protocol(NTP)

This is done using timedatectl set-ntp true

your system has two clocks

System Clock (software clock)

Hardware Clock (a.k.a RTC — Real Time Clock)

When your PC boots, it reads time from the hardware clock, then the kernel runs its own clock.

If these two clocks mismatch — you get all kinds of weird issues.

hwclock --systohc stands for Hardware clock <- System Clock "Take the current System Time and write it into the Hardware Clock"

When installing Linux (especially Arch), you:

Localization

From manual

To use the correct region and language specific formatting (like dates, currency, decimal separators),edit/etc/locale.genand uncomment the UTF-8localesyou will be using. Generate the locales by running:

locale-gen

All the formatting settings like

comes from a setting called locale. A locale = rules for language + region + formatting. Ex: en_US.UTF-8 English (United States)

Linux needs these compiled and stored so apps can actually use them

So locale-gen generates/compiles the locales you enabled in /etc/locale.gen

you uncomment what are all the options you want in /etc/locale.gen then run locale.gen to actually generate the compiled locale files for your system.

then create a /etc/locale.conf file and set which locale you want your system to use by default

TLDR; /etc/locale.gen - Enable/generate available locales /etc/locale.conf - Choose the default system locale

/etc/locale.conf LANG=en_US.UTF-8

Network Configuration

This file /etc/hostname exactly contains one line that denotes the hostname for your system without this name other devices in the network cannot refer to it, this device cannot identify itself when sending packets.

etc/hostname karthik-dev-machine

This is the file the init system (like systemd) reads It sets the system’s hostname with that value. All services started after this point inherit that hostname.

The temporary way to do this is

hostname karthik This resets after reboot.

Initramfs

What is initramfs?? why do we need it?

At the very start, the bootloader like GRUB loads the linux kernel into memory.

The kernel alone cannot access your real filesystem yet.

initramfs - The kernel's temporay mini-operating system initramfs - initial RAM filesystem.

its basically,

you can call it a mini rescue OS that runs before your actual Linus system does. it has kernel modules(drivers), binaries like ls, mount, lvm, cryptsetup and boot scripts

For example ext4 drive: initramfs loads disk + filesystem modules, mounts root switches to the real system simple. This is different for each drive lvm, LUKS, RAID etc..

now this pretty much explains why do we need

mkinitcpio -P initramfs depends on your system configuration. If you change any one of this

then old initramfs might not contain the right tools so we regenerate it with this command.

What is LVM? LVM = Logical Volume manager Problems before LVM:

I once myself faced this problem then i had to reinstall arch in a big partition. sadly i didn’t know about LVM back then.

LVM treats storage like RAM, just pool it and use what you need. its like a lego blocks for storage. Instead of physical partitions, you create virtual ones that you can resize, move, extend, shrink — while the system is running.

Some jargon:

your actual storage devices:

you convert them into PV's

pvcreate /dev/sda2

You combine multiple volume groups into one big pool.

vgcreate myvg /dev/sda2 /dev/sdb1

lvcreate -n root -L 40G myvg lvcreate -n home -L 100G myvg

These are completely virtual and you can resize them anytime.

TLDR;

Layer 1 PV (Physical Volumes)

Actual disks or partitions.

Layer 2 VG (Volume Group)

A pool/bucket made by combining physical volumes.

Layer 3 LV (Logical Volumes)

Virtual partitions created inside the volume group.

how resizing partitions LIVE is done in LVM

lvextend -L +10G /dev/myvg/root resize2fs /dev/myvg/root Boom, done. No reboot. No stress.

LVM can do more things:

take snapshots (like ZFS-lite) clone volumes resize storage on the fly This is how actual sysadmins run storage.

Root Password

passwd you know what this command does.

Boot Loader

A boot loader is a piece of software started by the firmware-UEFI or BIOS. It is responsible for loading the kernel with the wanted kernel parameters and any external initramfs images.

A boot manager presents a menu of boot options, or provides some other way to control the boot process i.e. it just runs other EFI executables. Ex: grub is a boot manager.

In the case of UEFI, the kernel itself can be directly launched by the UEFI using the EFI boot stub. A separate boot loader or a boot manager can still be used for the purpose of editing kernel parameters before booting.

Reboot

Optionally manually unmount all the partitions withumount -R /mnt: this allows noticing any "busy" partitions, and finding the cause withfuser(1).

now comes the question why do we need to unmount the /mnt partition before exiting?

It’s the same as we eject the pendrive from file explorer before physically removing the pendrive from the system.

It’s more of a safety procedure.

what might happen if you didn’t unmout the partition before reboot.

So now what is fuser? fuser = File user finder. It lets you check which processes are currently using a file or directory.

fuser -v /mnt This will show:

you can even kill all the processes using the /mnt folder

fuser -k /mnt fuser is also usefull in certain other scenarios as well for example you’re starting your app in port 3000 and the shell says port 3000 is already in use so you can use fuser in that scenario.

fuser -v 3000/tcp you can even kill it using this command:

fuser -k 3000/tcp where -k stands for kill.

now you might have got what fuser does and how it is useful: here for demonstration purposes i used fuser to check what processes are using the file system.

What issue does a “busy partition” cause???

you do umount and it says umount: /mnt: target is busy

That means something is still using that partition.

could be:

If you ignore this and shut down or reboot:

So its always a good idea to check busy mounts

Now that we’ve learnt what these series of commands in archlinux install manual do, it’s time to goon more on arch

and now don’t forget you’re not just a normal arch user you can brag with no hesitation “I use ARCH BTW”

if you want to read more about post-installation steps which are basically installing some gui’s and stuff that i assume you already know so i’m skipping those.

https://wiki.archlinux.org/title/Installation_guide

Anyway Happy Learning Peace 🕊️

👉 → https://x.com/kaizakinn