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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?

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migrated from stackoverflow.com Aug 21 '11 at 11:33

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

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2 Answers 2

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.

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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 : http://www.debuntu.org/recover-root-password-single-user-mode-and-grub

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 -.-

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2  
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