GRUB

 

clip_image002

Default:- default boot OS from list

Timeout:- how much time it’s wait for user selection, if not press any key then boot default OS.

Splashimage:- GUI of GRUB boot loader.

Title:- name of OS

root (hd0,0):- root partition on Hard disk.

Kernel:- which kernel load during boot.

 

To set run level in grub conf we put [ 1-5 ] in kernel parameter.

clip_image004

 

how to pass runlevel during boot time.

Press “e” to edit.

clip_image005

 

Again press “e” after select kernel part.

clip_image006

Put runlevel [ 1-5 ] in the end of kernel line with one space. Like “5”. Then press enter.

clip_image007

 

then press “b” to boot.

clip_image008

 

 

 

How to re-restore boot partition. [don’t run this command on running system ]

1st identify boot partition. Like “/dev/sda1”

 

clip_image009

 

Then boot OS in rescue mode with help of CD or ISO image.

Press “Esc” on this screen

clip_image010

Type “linux rescue” on command prompt.

clip_image011

Select “CD/DVD” from list.

clip_image012

Select “Network” No.

Select “Continue”

clip_image013

 

clip_image014

 

clip_image015

 

You can also re-set password of root user.

#passwd