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Possible Duplicate:
How do I add a user to the “sudo” group?

I've added myself back into the admin's group I think, by following this.

But I still can't do commands like:

sudo aptitude update

I get the message

oshirowanen is not in the sudoers file.  This incident will be reported.

How do I add myself into the sudoers group now that I am in the admin group?

Community
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oshirowanen
  • 3,977
  • Appears to be a duplicate ,But cant find it – Tachyons Apr 22 '12 at 14:35
  • @tachyons You might be thinking of this question about a similar but different error. There, a syntax error prevents running sudo. Here, entries may actually be missing. So I think an optimal answer here must also explain how to add the usual entries to allow administrators to use sudo. I've attempted such an answer. I do not recommend that this question be made a duplicate of that one, because unlike with a "little" syntax error, answers there don't clarify how to edit. – Eliah Kagan Jul 12 '12 at 17:17
  • After adding the user to the proper group, I still had to restart Ubuntu to get the updated group file to be recognized. Logging out and back in wasn't enough. – MarkHu May 06 '19 at 16:25

2 Answers2

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Login as root or su to get root prompt

type visudo

an editor will open find a line says

root ALL=(ALL) ALL

add one with your username below that

user ALL=(ALL) ALL

Type ctrl+x Type Y to the prompt

Sreevisakh
  • 1,516
9

If you're in the admin group (or the sudo group starting with Ubuntu 12.04) but that group isn't configured in /etc/sudoers to be able to run commands as root with sudo, you can fix that problem the same way you'd fix a broken sudoers file:

pkexec visudo

Then just edit the sudoers file to add whatever entries you need. In particular:

  • Ubuntu systems before 12.04, or those that were upgraded from a version before 12.04, should have this:

    # Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

  • Ubuntu 12.04 and later should have this (even if they also have the above lines because they were upgraded from an earlier release):

    # Allow members of group sudo to execute any command
%sudo   ALL=(ALL:ALL) ALL

This pkexec method works (on desktop systems) because Ubuntu systems with a GUI installed have two separate mechanisms for administrators to perform actions as root: sudo, and PolicyKit.

See this question about a different but similar problem, if you're curious and want more information:

Community
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Eliah Kagan
  • 117,780
  • The %sudo line existed already before 10.04. The only thing that's needed is to add the user to the sudo group (adduser <user> sudo). Still +1 for pkexec. – 0xC0000022L Jul 12 '12 at 17:24
  • @0xC0000022L The %admin line exists too. This question is about a system where those lines have somehow been removed, commented out, or modified so they no longer work. You're right in that it's arguably a good idea to have the sudo line in sudoers files in Ubuntu releases prior to 12.04, but practically speaking, it doesn't matter much. In contrast, you need the %admin line on any system where users are made administrators by inclusion in the admin group, and you need the %sudo line on a system where users are made administrators by inclusion in the sudo group. – Eliah Kagan Jul 12 '12 at 17:30