Users, groups and directory access

[A.J. Bonnema]

Matthew Miller wrote:
> On Wed, May 05, 2004 at 03:30:07AM -0500, David L Norris wrote:
> 
>># root can change john's group membership like this
>>usermod -G proj john
> 
> 
> This is bad because it *replaces* the current list of groups. If john was
> previously a member of 'staff' or 'proj2', that would be removed. This is
> why gpasswd -a is usually better.

Do you mean, only one group will result from this command? I mean, will 
the primary group be replaced too? I executed this command and after 
groups I got: john, as the only group. After logoff/logon I got: john 
proj, as the groups output.

However, I'll do some experiments on a fake user to try this one out.
> 
> 
> 
> 
>>>How can john change his primary group on the commandline?
>>
>>newgrp proj
> 
> 
> But this is basically obsolete -- there's almost never a reason to do this.
> 

Then I wonder what the use of a primary group is: is there any 
preference in the system for the primary group? In what circomstance?

Guus -- never too late to learn --
-- 
A.J. Bonnema, Leiden The Netherlands,
user #328198 (Linux Counter http://counter.li.org)