Grub and Fstab Configuration

To simplify filling in the UUID fields in /etc/fstab, the following commands use blkid to extract the UUID of each partition. The blkid tool prints device information in the form UUID="xxxx-xxxx", and the pipeline below removes the quotes so the value can be inserted directly into the file.

export DRIVE=/dev/vda
export ROOT=$(blkid -o value -s UUID ${DRIVE}3)
export SWAP=$(blkid -o value -s UUID ${DRIVE}2)
export UEFI=$(blkid -o value -s UUID ${DRIVE}1)
export PARTROOT=$(blkid -o value -s PARTUUID ${DRIVE}3)

cat > /etc/fstab <<EOF
# Begin /etc/fstab

# file system  mount-point    type     options             dump  fsck
#                                                                order

$ROOT   /            ext4   defaults                                1  1
$SWAP   swap         swap   pri=1                                   0  0
$UEFI   /boot/efi    vfat   noauto,codepage=437,iocharset=iso8859-1 0  1

# End /etc/fstab
EOF

In the same way, GRUB can automatically locate the root filesystem by UUID using the search command. Here, blkid is again used to extract the filesystem UUID from the partition so that it can be inserted directly into the configuration.

cat > /boot/grub/grub.cfg <<EOF
# Begin /boot/grub/grub.cfg
set default=0
set timeout=10

insmod part_gpt
insmod ext2
insmod efi_gop
insmod efi_uga

search --no-floppy --fs-uuid --set=root $(blkid /dev/vda3 | awk '{print $2}' | sed 's/"//g')
set gfxpayload=1280x1024x32

menuentry "GNU/Linux, Linux-6.12.58-lfs-r12.4-45-systemd" {
    linux   /boot/vmlinuz-6.12.58-lfs-r12.4-45-systemd root=PARTUUID=$PARTROOT ro

}
EOF

unset ROOT SWAP UEFI PARTROOT