SUMMARY: "groups" command oddities

From: Charles Sebold <sebold_at_lcms.org>
Date: Thu, 02 Sep 1999 14:55:36 -0500

Many thanks to:

John Speno
Sheryl Lemma

Here was the solution suggested or offered by both (I would think that this
could be considered a bug, but perhaps not):

All of my users (after several abortive attempts at revamping our site's
security) had "users" as their primary group (i.e., in /etc/passwd), but
they were all listed in /etc/groups under "users" as well, because they had
at some point had another primary group and "users" as a supplementary
group. Everyone who was both a primary member of "users" and a supplementary
member of "users" had this problem, which was solved when I applied the
Alexandrian solution to this Gordian knot and removed all their entries from
"users" in /etc/groups. I guess that running "groups" with no username
queries the process under which you are running to get its information, whereas
running it with a username checks against /etc/passwd and /etc/groups (and
whereever else this might be).

Considering I made all my changes with either /usr/sbin/usermod or dxaccounts
up to this point, I am guessing that this would be classified as a bug, or
at least a "loose end."

On Thu, Sep 02, 1999 at 02:00:41PM -0500, Charles Sebold wrote:
> Managers:
>
> I have an odd question about the "groups" command. I'm running 4.0D, patch
> level 3.
>
> Here is the output of the command, run two different ways (seboldcr is my
> username):
>
> $ groups
> users system mslive mstest llllive llltest ae_users lllpower mspower prog fndtest msdev helpdesk
> $ groups seboldcr
> system users users users users users mslive mstest llllive llltest ae_users lllpower mspower prog fndtest msdev helpdesk
>
> Notice how the group "users" is repeated 5 times in the second version of
> the command.
>
> Any idea why this would be? In the /etc/groups file, my name only shows up
> once in users.
>
> This is also the case with "id -Gn":
>
> $ id -Gn
> users system mslive mstest llllive llltest ae_users lllpower mspower prog fndtest msdev helpdesk
> $ id -Gn seboldcr
> system users users users users users mslive mstest llllive llltest ae_users lllpower mspower prog fndtest msdev helpdesk
>
> (I tried that because in Linux I know that the two commands are basically
> identical, and it would seem that in Tru64 Unix they at least have identical
> problems, for me.)
>
> This is an issue because we have scripts in our database system that have to
> check group membership this way (rather than using system calls).
>
> I will summarize.
>
> --
> Charles Sebold, UNIX Systems Specialist
> LCMS - Office of Information Systems
> *** Opinions expressed herein are not necessarily ***
> *** those of the Lutheran Church - Missouri Synod ***
> --
> 21st of Elul, 5759
> --
> Save the Whales -- Harpoon a Honda.

-- 
Charles Sebold, UNIX Systems Specialist
LCMS - Office of Information Systems
*** Opinions expressed herein are not necessarily ***
*** those of the Lutheran Church - Missouri Synod ***
--
21st of Elul, 5759
--
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Received on Thu Sep 02 1999 - 19:57:05 NZST

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