Re: groups versus groups

[James Youngman]

On 5/28/07, dave <address@hidden> wrote:
> if i log in as dhorner and type groups it says i am in one set of groups
> but if i type in
> groups dhorner it says i am in other groups.

This is not unusual; on the system I am using here, for example, the
login process adds me to various additional groups depending on how I
log in.  On my system this is controlled by /etc/security/group.conf.
For example, my groups include "audio" if I log in on the console.
The mechanisms used to do this are not part of coreutils.

> so is there a difference in
> me as a user and me as process i am in?

Yes there is a difference between users and processes.  You are not in
a process.  As far as the system is concerned, you are a user, not a
process.  At any given time, a process has an effective user ID.
Usually, it's the user ID of the user who started the process.

> THese file privs has always
> driven me nuts.

I'm sorry to hear it.  You might find it helpful to read up on Unix
concepts and administration.  Try for example
http://www.debian.org/doc/manuals/debian-tutorial/ though there are
plenty of other books on the subject.

> In a dir if i own the diri can add a dir or save a file
> here but if i am part of a group that owns the dir i cant. What is the
> def truth about who can use a dir?

Read up about permissions in the documentation for the system you are
using.   The precise details of how permissions are enforced are
spcific to a particular implementation.   These are enforced by the
kernel, not coreutils.  That means that the coreutils documentation
cannot reliably tell you all the details of the system you are using
it on.

James.