reset root password- ubuntu boot in single user mode

For that press down the “shift” key while booting and you will get the GRUB boot menu.

Normally the top GRUB entry will be pointing to your normal boot entries. It will look similar to:

grub-screen-1

Press the ‘e’ key to edit the kernel parameters.

Now what you see are the boot entries. Now find the kernel line and append “init=/bin/bash” to it.

Look near the bottom of the list of commands for lines similar to

linux /boot/vmlinuz-3.2.0-24-generic root=UUID=bc6f8146-1523-46a6-8b\
6a-64b819ccf2b7 ro quiet splash

replace ro quiet spash with rw init=/bin/bash

linux /boot/vmlinuz-3.2.0-24-generic root=UUID=bc6f8146-1523-46a6-8b\
6a-64b819ccf2b7 rw init=/bin/bash

Press either Ctrl+X or F10 to boot using these kernel options.

mount -n -o remount,rw /

Now changing the root password is a piece of cake!!! just type in:

passwd root