Chroot

Create

Build env

mkdir -p /var/chroot && cd /var/chroot
mkdir my_os_folder

apt install debootstrap
debootstrap debian my_os_folder

mkdir -p my_os_folder/{proc,dev,sys,tmp}
chmod 1733 my_os_folder/tmp

chroot and dev, proc, sys

Posted on May 1, 2012

chroot is a great tool to rescue systems. But a limitation is that /dev, /sys and /proc are not mounted by default but needed for many tasks. This can be done by using mount –bind on the host. Here an example how to get a functional chroot:

mount /dev/sda1 /mnt
cd /mnt
mount -t proc proc proc/
mount -t sysfs sys sys/
mount -o bind /dev dev/
chroot .

in case of EFI

https://wiki.debian.org/GrubEFIReinstall

mount -t efivarfs none /sys/firmware/efi/efivars

for i in /dev /dev/pts /proc /sys /sys/firmware/efi/efivars /run; do mount -B $i /mnt/$i; done

chroot /mnt

grub-install /dev/sdb

update-grub