From Linux Config Wiki

• Author: Lubos Rendek
• Date: 15.5.2008

Introduction

This method of reseting/recovering of lost Linux root password should work on most of the linux distributions. I have tested this method for couple years already, starting with debian woody trought redhat and suse to ubuntu hardy. If you run lilo boot loader instead of grub you can use the same method but with some modifications on how to edit lilo boot prompt.

Edit Grub boot menu options

First you need to get into grub menu options. This menu is displayed right at the beginning of the boot. If you cannot see your grub menu options press "ESC' key. You should get something similar to this:

Now we attempt to edit grub's boot option. Press "e" to edit the first grub menu option and navigate to kernel line:

Press "e" key again to edit and remove:

quiet splash

and add:

init=/bin/bash

You may have some different boot options but the main part you need to change/add is init=/bin/bash. You will get something similar to this:

Press enter:

At this point, we have edited grub boot menu, and we are ready to boot. Press "b" key to boot.

Remount / and /proc

After successfully boot you will be presented with bash command prompt:

On some linux systems, you will need to completely mount / and /proc partitions. To do that, enter following commands:

mount -o remount,rw /
mount -o remount,rw /proc

• NOTE: If you are not sure that if your partition is already mounted RW, run the above command anyway as, otherewise on some systems you will not be able reset your root password. If you fail to do so, you get this error displayed on the screen:

passwd: Authentication token lock busy

• NOTE: On some Linux distributions, you will have /proc mounted already if this is not your case, just run following command:

mount /proc

reset / recover forgotten linux root password

To reset a actual root password is now simple as typing :

passwd

Reboot

Before you reboot is recommended but not compulsory to run

sync

command. Your job of reseting a linux root password is accomplished.