Minimal instructions for installing Arch Linux on GPT or MBR on UEFI or Legacy BIOS

arch-linux-install.sh

# Download an Arch ISO from https://www.archlinux.org and copy it to a USB drive:
sudo dd bs=4M if=archlinux-2019.01.01-x86_64.iso of=/dev/sdb status=progress oflag=sync
# then plug it into the device of your preference, boot it and start the installation process.

# Installation process:
# Set UK keymap
loadkeys uk

# Set up partitions (MBR)
parted /dev/sdX mklabel msdos
cfdisk /dev/sdX
# 1 - 1G primary partition, set the bootable flag
# 2 - 100% primary partition

# OR

# Set up partitions (GPT)
cgdisk /dev/sdX
# 1 - [ EFI: 100M | Legacy: 1G ] partition # Hex code: [ EFI: ef00 | Legacy: ef02 ]
# 2 - 250M partition # Hex code 8300 ( Not needed for a legacy install, if you chose not to make this partition, /dev/sdX3 becomes /dev/sdX2 in this guide! )
# 3 - 100% partiton # Hex code 8300

# May need to reboot here if any of the next commands fail with an error!
# reboot

# Set the filesystems
#Legacy:
mkfs.ext2 /dev/sdX1

#OR

#EFI:
mkfs.vfat -F32 /dev/sdX1
mkfs.ext2 /dev/sdX2

# Create the encryptied partitions
cryptsetup luksFormat --type luks2 --cipher aes-xts-plain64 --key-size 512 --hash sha256 /dev/sdX3
cryptsetup luksOpen /dev/sdX3 sysroot

# Set up LVM
pvcreate /dev/mapper/sysroot
vgcreate arch /dev/mapper/sysroot
lvcreate --size 2G arch --name swap
lvcreate -l +100%FREE arch --name root

# Set the filesystems
mkfs.xfs /dev/mapper/arch-root
mkswap /dev/mapper/arch-swap

# Mount the new filesystem
mount /dev/mapper/arch-root /mnt
swapon /dev/mapper/arch-swap
mkdir /mnt/boot

# Legacy:
mount /dev/sdX1 /mnt/boot

# OR

# EFI:
mount /dev/sdX2 /mnt/boot
mkdir /mnt/boot/efi
mount /dev/sdX1 /mnt/boot/efi


# Enable wifi if required
wifi-menu

# Install the system and necessary/favorable utilities, make sure to change this!
pacstrap /mnt base base-devel fish nano vim git efibootmgr grub grub-efi-x86_64 dialog wpa_supplicant lsb-release

# Set up fstab
genfstab -pU /mnt >> /mnt/etc/fstab

# Edit fstab if using an SSD: change relatime on all non-boot partitions to noatime and add discard
nano /mnt/etc/fstab

# Chroot into the newly installed arch system
arch-chroot /mnt /bin/fish

# Setup system clock (https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)
ln -sf /usr/share/zoneinfo/Europe/Jersey /etc/localtime
hwclock --systohc --utc

# Set hostname
echo somehostname > /etc/hostname

# Update locales
nano /etc/locale.gen # uncomment the line containing en_US.UTF-8 UTF-8
echo LANG=en_US.UTF-8 >> /etc/locale.conf
locale-gen

# Set root password
passwd

# Add a new user (remove -s /bin/fish if you want bash instead)
useradd -m -g users -G wheel -s /bin/fish MYUSERNAME
passwd MYUSERNAME

# Configure suders
nano /etc/sudoers
# Uncomment the line containing %wheel ALL=(ALL) ALL

# Configure mkinitcpio
nano /etc/mkinitcpio.conf
# Add 'keymap encrypt lvm2 resume' to HOOKS just before 'filesystems'

# Set up a bootloader (choose between legacy and EFI):

# Legacy (grub)
grub-install --target=i386-pc /dev/sdX

# If you encounter "WARNING: Device /dev/xxx not initialized in udev database even after waiting 10000000 microseconds." you may need to provide /run/lvm/ access to the chroot environment using: 
exit # exit out of the chroot for the time being
mkdir /mnt/hostlvm
mount --bind /run/lvm /mnt/hostlvm
arch-chroot /mnt /bin/fish
ln -s /hostlvm /run/lvm
# You will need to re-run the "grub-install" command as instructed above after this.

nano /etc/default/grub
# Set GRUB_CMDLINE_LINUX as "cryptdevice=/dev/sdX3:luks root=/dev/mapper/arch-root resume=/dev/mapper/arch-swap"
# and uncomment the line containing GRUB_ENABLE_CRYPTODISK=y
grub-mkconfig -o /boot/grub/grub.cfg

# OR

# EFI (grub)
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ArchLinux
nano /etc/default/grub
# Set GRUB_CMDLINE_LINUX as "cryptdevice=/dev/sdX3:luks root=/dev/mapper/arch-root resume=/dev/mapper/arch-swap"
# and uncomment the line containing GRUB_ENABLE_CRYPTODISK=y

# OR

# EFI (systemd-boot)
bootctl --path=/boot/efi install
nano /boot/efi/loader/entries/arch.conf
# Set options as follows:
#title   Arch Linux
#linux   /vmlinuz-linux
#initrd  /initramfs-linux.img
#initrd  /initramfs-linux-fallback.img
#options cryptdevice=/dev/sdX3:lvm root=/dev/mapper/arch-root resume=/dev/mapper/arch-swap rw 

# Regenerate initrd image
mkinitcpio -p linux

# Exit the chroot
exit

# Unmount all partitions
umount -R /mnt
swapoff -a

# Reboot into your new Arch Linux install.
reboot


# If at any time you need to get back into chroot via installation media:
cryptsetup luksOpen /dev/sdX3 sysroot
mount /dev/mapper/arch-root /mnt

# Legacy:
mount /dev/sdX1 /mnt/boot

# OR

# EFI:
mount /dev/sdX2 /mnt/boot
mount /dev/sdX1 /mnt/boot/efi

arch-chroot /mnt /bin/fish