Why do I get an ‘authentication failure’ when trying to use sudo from the command line in Ubuntu?

Jpa42 May 5, 2014
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My operating system is Ubuntu 14.04. I have two issues:

  • When working on the GUI level whenever the operating system asks me to authenticate, I enter the ‘administrator’s password and all is fine.
  • When working on the command line, the OS shows nicely ‘myusername@mycomputer’. As soon as I enter the ‘su or su -or sudo’ and a command the OS asks me for the (administrator user) password and rejects me with an ‘authentication failure’.

Any idea why? Is there any fix easy enough, apart from reloading the whole thing (OS) once more ? (I’m a newbie to Linux).

  1. Jpa42
    May 6, 2014 at 3:28 pm

    Great ! Thanks Bruce. Got the trick now. From now on I'll jump to the command line thru 'sudo'. Bye. JPA

  2. Bruce E
    May 6, 2014 at 10:23 am

    When using the 'sudo' command, you need to enter YOUR password, not root's password.

    If you are executing the 'su' command, you need root's password.