grub rescue

It could happen that your PC, after some operations (i.g. with gdisk) doesn’t start booting and you are therefore in grub rescue prompt. A very unpleasant situation.

The steps to follow are:

1. see what are the partitions, with the command ls
   • you should see something like: (hd0)(hd0,msdos1)(hd0,msdos2)(hd1)(hd1,gpt1)
2. understand what is the right partition to boot (i.g. hd0,gpt2):
   • you can list a single partition to see what it contains, with the command ls (hd0,gpt2). You should be able to see if a partition is the right one.
3. give the command set prefix=(hd0,gpt2)/boot/grub
4. give the command set root=(hd0,gpt2)/ root=/dev/sda2 (if the right partition is hd0,gpt2 the name is /dev/sda2, if it was hd1,gpt3 it would be /dev/sdb3)
5. give the command insmod normal
6. give the command: normal (or boot)

In this way the system should start with the expected partition.