Grub starts in command line after reboot

<aside> 💡 Manually booting

Identify the boot partition

grub > ls
(hd0,gpt1) (hd0,gpt2) (hd0,gpt3) 

Load the normal module (for configuration file), Linux module (for similarity), boot module (for finding grub.cfg) then load the configuration file

grub > insmod normal
grub > insmod linux
grub > insmod boot
grub > normal

Set root partition and load the kernel and initrd images

grub > root=(hd0,gpt3)
grub > linux /boot/vmlinuz-x.x.x-xx-generic root=/dev/sda3
grub > initrd /boot/initrd.img-x.x.x-xx-generic
grub > boot

Then you should reinstall grub

sudo grub-install /dev/sda

</aside>