Recover root password for Linux

GRUB:

You may be able to boot single-user mode directly. If your system boots, but does not allow you to log in when it has completed booting, try single-user mode.

If you are using GRUB, use the following steps to boot into single-user mode:

1. If you have a GRUB password configured, type p and enter the password.
2. Select Red Hat Linux with the version of the kernel that you wish to boot and type e for edit. You will be presented with a list of items in the configuration file for the title you just selected.
3. Select the line that starts with kernel and type e to edit the line.
4. Go to the end of the line and type single as a separate word (press the [Spacebar] and then type single). Press [Enter] to exit edit mode.
5. Back at the GRUB screen, type b to boot into single user mode.

After you enter into single user mode type passwd command to change password

            #passwd

            New password:******

            Confirm password: *****

Type init 5 to go into run level 5 which is GUI.

LILO:

If you are using LILO, specify one of these options at the LILO boot prompt (if you are using the graphical LILO, you must press [Ctrl]-[x] to exit the graphical screen and go to the boot: prompt):

boot: linux single boot: linux emergency