Grub shell = grub-install

In the past, when grub information on the machine was lost or damaged, use rescue mode to enter and then reinstall grub-install/dev/SDA.
For some reason, grub-install/dev/SDA may encounter more or less problems during execution. We can also use another method to replace
Go to grub shell mode.
As follows:

GNU grub version 0.97 (640 K lower/3072 K upper memory)

[Minimal bash-like line editing is supported. For the first word, Tab
Lists possible command completions. Anywhere else tab lists the possible
Completions of a device/filename.]

Grub> root (hd0, 4) # partition where the/boot directory is located
Grub> setup (hd0) # location where grub is to be installed
In this way, you can also start the following grub-install/dev/SDA command.

 

 

Reproduced from: http://blog.chinaunix.net/space.php? Uid = 9098575 & Do = Blog & id = 2435859