Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

This question already has an answer here:

During the installation process I was asked to set a password. I chose a password (a strong one) and everything goes smoothly every time I log in. Problems arise whenever I resort to "sudo" or "su" commands ...

I mean, if I type "sudo or "su" I'm compelled to provide a password and whenever I type the password I choose during the installation process I get this error:

Authentication failure

Can someone help me?

share|improve this question

migrated from Aug 21 '11 at 11:33

This question came from our site for professional and enthusiast programmers.

marked as duplicate by Eliah Kagan, Alaa Ali, RobotHumans, Eric Carvalho, Tim Aug 12 '14 at 9:15

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Maybe the error comes from the way you use sudo.

Sudo should be used by your regular (non-root) user the following way:

sudo command

When prompted for a password, you should enter your user's password or in other words, the password used at login.

share|improve this answer

This is known from Ubuntu, you did not set root password.

the password you have set is your user's password and has no relation to the root.

please take a look at this link and see if it can help :

P.S : I left ubuntu for good just because of these lame features, I'm a developer and I need to function with everything, why limit me -.-

share|improve this answer
Sudo prompts for your current user password, not the root password. It's perfectly safe to run an Ubuntu installation as it's intended to be run: without a root password set. It's for security purposes. That being said you can always set the root password at anytime. – Marco Ceppi Aug 21 '11 at 12:19