Linux under Grub.cnf detailed

Tag: Boot does not show splash boot expired art image rhel6 verify

Grub.conf is related to the system startup key for resetting the password. The small case ...

1 , Introduction

after Red Hat Linux7.2, the default boot loader changes from Ltlo to Grub. This bootloader allows the user to choose when and how to boot a bootable operating system that is installed on the computer's hard disk.

2 , Description

Variable description

#:                 to annotate the menu configuration document.
default:      Specifies the default operating system. If 0, the default startup add-on, for multiple startup items, you can adjust the number
timeout:      Configures the time limit (in seconds) before grub starts by default. In 30 seconds, grub waits for how long to load the kernel
splashimage:    Specifies the location of the background image used by default grub boot.
hiddenmenu:    When this command is used, he does not display the Grub menu interface and loads the default entry after the timeout period expires. The user can see the standard Grub menu by pressing the [ESC] key. The ability to add # or delete in front of it to achieve the purpose of displaying menu excuses.
title:         Configure options displayed in the Grub menu ...
kernel:        specifies the Linux kernel address.
initrd:        Specifies the initial memory disk address.
rootnoverify:   Specifies the partition where the boot document is located for sensitive operating systems such as Windows XP. The
Chainloader:  +1 indicates that the first sector in the specified partition is looking for a boot document.

Description:

　　The password variable was not listed because I did not select the boot load password when I installed the system. When this variable is used, he is able to prevent users who do not know the password from editing the menu item .

Ways to add passwords to grub:

Grub-md5-crypt #输入MD5加密的密码

Timeout 6 #后面, is a global password policy

#password Xxoo
Password--md5 $1$yhi9t/$Rcpn 3mr6kkdmyzhlylrqa/#MD5加密后的密码 #两个-

Note: Not adding lock is only valid for gurb configuration, plus, after reboot, verification is required

Lock //Locks Linux requires password #注释掉, only needs to be verified when GRUB is modified

Root (hd0,0)//HDD hd0

00 Restart requires authentication

01 Enter password P

Just lock the Grub boot entry for modification

Boot also locked, need to verify

Note: password--md5 #是两个-

3. Example Analysis

Booting the operating system under GRUB command line

Booting the Windows operating system

Root (hd0,//Press the TAB key to view

Rootnoverify (hd0,0)//Mount Partition

Makeactive//Activation

Chainloader +1//Chain-mount

Boot//boot

Booting Linux operations

Root (hd0,

Rootnoverify (hd0,0)//Mount Partition

Kernel/vmlinuz-2.4.20-8 ro root=label=///load Linux system kernel files

INITRD/INITRD-2.4.20-8.IMG//Loading system files

Boot//boot

The root password is missing from the grub recovery method #rhel6.5

Restart the system, when entering the Grub interface, select the Linux bar, press the "E" key to press the E key again to edit, space input single or 1

Input passwd Change password Vi/etc/passwd/etc/shadow x encrypted ciphertext

Example

# grub.conf generated by Anaconda

#

# Note that you don't have the to rerun grub aftermaking changes to the This file

# notice:you has a/boot partition. Thismeans that

# all kernel and INITRD paths is relative to/boot/, eg.

# root (hd0,0)

# kernel/vmlinuz-version RO root=/dev/sda2

# initrd/initrd-version.img

#boot =/DEV/SDA

DEFAULT=0 Specifies the default operating system. If 0, the operating system shown in the first paragraph is automatically started when no user input is entered.

Timeout=10 configures the time limit (in seconds) before grub starts default. In the 30 seconds.

Splashimage= (hd0,0)/grub/splash.xpm.gz Specifies the location of the background image used by default grub boot

PASSWORD–-MD5 $1$Z5GDB$KTCO9CMOIQ1AXFNB.E8L10//Global password

Title Red Hat Linux (2.4.20-8) configuration options shown in the Grub menu

Lock //Locks Linux requires password #注释掉, only needs to be verified when GRUB is modified

Root (hd0,0)//HDD hd0

Kernel/vmlinuz-2.4.20-8 ro root=label=///specify Linux kernel address

INITRD/INITRD-2.4.20-8.IMG//Specify initial memory disk address

Title Wndows XP

Rootnoverify (hd0,0) specifies the partition where the boot document is located for sensitive operating systems such as Windows XP.

Chainloader +1 +1 indicates that the first sector in the specified partition is looking for a boot document

Linux under Grub.cnf detailed