Reset Your Ubuntu Password
Reboot your computer, and then as soon as you see the GRUB Loading screen, make sure to hit the ESC key so that you can get to the menu.
Root Shell – Easy Method
Choose the “recovery mode” item on the Grub menu, found right below the default kernel option.
Then choose “Drop to root shell prompt” from the menu that will get you to the root prompt.
Alternate Root Shell Method
If the recovery mode option is missing, the alternate way to manually edit the grub options to allow for a root shell is to choose the regular boot kernel that you use, and then use the “e” key to choose to edit that boot option.
Now just hit the down arrow key over to the “kernel” option, and then use the “e” key to switch to edit mode for the kernel option.
Remove the “ro quiet splash” part with the backspace key, and then add this onto the end:
After hitting enter after adjusting the kernel line, use the B key to choose to boot with that option to boot a command prompt.
Changing the Password
You can use the following command to reset your password:
For password input the following command
use the following commands to reboot your system after you have changed your password. (The sync command makes sure to write out data to the disk before rebooting)
The –f parameter is necessary to get the reboot command to work after syncing .
you can now log in using your new password.