Chroot on Arch Linux from LIVE CD to fix other installation

GETTING CHROOT on arch linux.

Mostly use this:
https://forum.artixlinux.org/index.php/topic,103.0.html

Text with my updates:

#-------------------------------#
#  Standard chroot      #
#-------------------------------#

First, I used an old LiveDVD/CD from 2019. This is 2020. It works just fine.

This command manually Identify and Prepare the Installed Partition(s)

1. Open your terminal and start a root session: su

2. List all your partitions: lsblk -f (commandlinekid update: was /sda3)

3. Mount your system partition. The syntax to mount the system partition is: mount /dev/[partition_to_mount] /mnt

Example: if the system partition is /dev/sda3, this will be mounted using the following command:  mount /dev/sda3 /mnt  if a separate partition /dev/sda1 has been used for the GRUB, mount it with the following command: mount /dev/sda1 /mnt/boot

4. Change to the root directory of your mounted partitions: cd /mnt

To complete the operation, and to mount completely the file system, it will be necessary to enter a series of commands in the following order:

mount -t proc proc /mnt/proc
mount -t sysfs sys /mnt/sys
mount -o bind /dev /mnt/dev
mount -o bind /run /mnt/run
mount -t devpts pts /mnt/dev/pts/

cp /etc/resolv.conf /mnt/etc/resolv.conf

chroot /mnt

DONE and now you are positioned on the chroot-ed file system, where all your command will act.

#---------------------------------#
# LUKS Partition chroot #
#---------------------------------#

1) Boot with a liveUSB

2) Open a Terminal session

3) Identify the hd partition: lsblk

In this example I suppose that:
/dev/sda1 is the /boot partition
/dev/sda2 is the LUKS encrypted partition

NOTE: replace sda1 or sda2 with the partition name that you get with the lsblk command

$ su
$ cryptsetup open --type luks /dev/sda2 root # where sda2 is the encrypted device
$ mount /dev/mapper/root /mnt
$ mount /dev/sda1 /mnt/boot # mount here the boot partition
$ mount -t proc proc /mnt/proc
$ mount -t sysfs sys /mnt/sys
$ mount -o bind /dev /mnt/dev
$ mount -o bind /run /mnt/run
$ mount -t devpts pts /mnt/dev/pts

$ cp /etc/resolv.conf /mnt/etc/resolv.conf

$ chroot /mnt

commandlinekid update (chroot DID work, but if not, try arch-chroot)

commandlinekid  update (if chroot /mnt doesn't work, do this: chroot /mnt /bin/bash)

THEN RUN THESE TWO COMMANDS:

pacman Syu
mkinitcpio -p linux

Then reboot

(second command I got from here: https://www.soimort.org/notes/170407/)