When we forget the root password is not set if the GRUB password (or know the GRUB password) We can use a single-user approach to modify the password, which we have to modify the root password with the CD-ROM

1, the system CD-ROM into the drive, set the boot drive.


2, select F2 to enter System Repair enter the command: linux rescue


3, the following appears several options and install the same system.

4, when there should remember this when prompted, he tips the command:

# chroot / mnt / sysimage


5, the next step is to get to change your password, we first:

# chroot / mnt / sysimage # # does not recognize writable mode can not enter.


6 Finally, run the command: passwd

New Password
Confirm New Password

7 Restart your computer.

How to grub Encryption: In order to grub is divided into two kinds of secret, one explicit, the second is the use of MD5 encryption algorithm.
Plaintext encryption: Editing grub.conf file
vim / boor / grub / grub.conf add the following in the default = 0 line password = 1234567890 (this is in clear text password)

MD5 Encryption: first order

# grub-md5-crypt

Calculate the MD5 value, and then copy this value into the grub.conf file

password - md5 $ BYxEn $ e5X/xOTS2pTpPPWtgIMhU1 (this is to use MD5 encrypted value)