[clug] Blank CD-R Disc

Bryan Kilgallin kilgallin at iinet.net.au
Sun Sep 2 11:25:31 UTC 2018

I wrote:

> I'm going to reboot into recovery mode. Then, I am reading, I need to 
> remount the filesystem with write permissions. With the aim of editing 
> the /etc/group file.

The su/sudo issue afflicts both my tower-pc and my laptop. Maybe the 
latter got it via restore from the former's backup?

Recently these commands have failed.
su reports "Authentication failure".
sudo reports that my username
"is not in the sudoers file.  This incident will be reported.".

I fixed the problem on my tower-pc, by booting via GRUB, into recovery 
mode. Thereby I dropped to root shell prompt. And I remounted the 
filesystem with write permissions. Then I edited the /etc/group file, 
adding my username to many groups.

After that, sudo worked. But su still returned the authentication error.

Unfortunately that fix didn't last. Sudo stopped working, giving the 
original error. And my edited /etc/group file was renamed to "group-". 
Its replacement only listed my username as follows.
     cdrom:x:24:<username>, and

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