[clug] Blank CD-R Disc

[Scott Ferguson]

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
Defaults
secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
root    ALL=(ALL:ALL) ALL
%sudo   ALL=(ALL:ALL) ALL




Kind regards

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