ge.sh

#vi /boot/grub/grub.cfg

mount /dev/sda1 /mnt
vi /mnt/boot/grub/grub.cfg
cp /mnt/boot/grub/grub.cfg /boot/grub/grub.cfg
umount /mnt
df





/etc/default/grub 수정

GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=y

# Uncomment to disable generation of recovery mode menu entries
GRUB_DISABLE_RECOVERY="true"




centos

uname -a
#awk -F' '$1=="menuentry " {print i++ " : " $2}' /boot/grub2/grub.cfg
awk -F' '$1=="menuentry " {print i++ " : " $2}' /boot/efi/EFI/centos/grub.cfg 
read -p "input num: " num
#grub2-set-default.real $num
grub2-set-default $num
grub2-editenv list



ubuntu

uname -a
awk -F' '$1=="menuentry " {print i++ " : " $2}' /boot/grub/grub.cfg
read -p "input num: " num
#grub-set-default.real $num
grub-set-default $num
grub-editenv list