[clug] Blank CD-R Disc

Scott Ferguson scott.ferguson.clug at gmail.com
Sun Sep 2 11:02:49 UTC 2018

On 02/09/18 19:00, Bryan Kilgallin via linux wrote:
> Dear Scott:
>>> As I have been trying to explain, my username cannot use sudo!
>>> {gpasswd: Permission denied.}
>> Odd, by default, on Ubuntu, members of the sudo group have sudo
>> privileges.
> That was the case. But I have accidentally deleted my username from the
> sudo group!
>> And by default, all users are members of the sudo group.
> As above, now my username appears to have been deleted from it!
>> To diagnose the problem preparatory to fixing it, please post the output
>> of the following command (run as brian, or whatever your username is):-
>> su -c "grep '^[^#]' /etc/sudoers"
> {su: Authentication failure}

Which (also) sounds like a file permissions problem....

/etc/shadow should be 640 and /etc/sudoers should be 440

e.g.(note that you don't need special permissions to run ls on these
files - only to read or modify them):-
for i in shadow sudoers;do ls -al /etc/$i;done
-rw-r----- 1 root shadow 1434 May 31 00:38 /etc/shadow
-r--r----- 1 root root 669 Jan 14  2017 /etc/sudoers

If the file permissions are not right, then it won't matter whether you
edit those files or not.

NOTE: (Important) you should only edit /etc/sudoers with visudo

The default contents of /etc/sudoers should be:-
Defaults        env_reset
Defaults        mail_badpass
root    ALL=(ALL:ALL) ALL
%sudo   ALL=(ALL:ALL) ALL

Kind regards

    A: Because we read from top to bottom, left to right.
    Q: Why should I start my reply below the quoted text?

    A: Because it messes up the order in which people normally read text.
    Q: Why is top-posting such a bad thing?

    A: The lost context.
    Q: What makes top-posted replies harder to read than bottom-posted?

    A: Yes.
    Q: Should I trim down the quoted part of an email to which I'm reply


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