“username” is not in the sudoer list - how do I get back in there

Question

I use Ubuntu 9.10
I changed my password. After I restarted my machine and tried to do sudo whatever... I got

"username" is not in the sudoer list.

What should I do to get back in there?

Answer 1

On Ubuntu, you need to be in the admin group. If you have left the admin group, then try booting to the recovery console:

• when booting, hold down the shift key to bring up the grub menu
• select the second option (which should say "recovery mode" or "recovery console" at the end of the line)
• then add your user to the admin group again

# usermod -a -G admin your username

• then reboot again and you should be able to do sudo stuff again.

Answer 2

You have to check the /etc/sudoers file.

It is worth it to note that you will have to be root in order to read / edit the file. See visudo.