1: Can a file/dir belong to many groups and users? (excessive, yes, but I'm dealing with a windows disc here ^_^)
2: If 1 is yes, how do I do that?
3: How do I view what groups a user is in?
4: How do I change what groups a user is in?

/Marcus

1-2. Short answer, is no... However....
Each file or directory has one owner and one group designation. What I would do to achieve similar results, is to create a new group that contains the users from the various other
groups that would need to access whatever file/directory, and set that file to belong to the group that you setup. It makes for a little more on the maintenance side (though not much), but it should still get the job done.

3-4. /etc/group - This will contain a list of all of the groups and list all of the users in each group. This is also what you modify when moving people in/out of groups.


Hope that helps.

(1) Nope -- in the traditional Unix sense, a file system belongs to one user, and one group. If user/group access permissions are not sufficient, many filesystems these days support access control lists (ACLs) a la Windows, but it's something that usually has to be specially enabled.

(3) id <user> or groups <user>

(4) The user's primary group is the 4th field in /etc/passwd -- otherwise you can add the user to the appropraite group entry in /etc/group. An /etc/group entry looks like

* group passwords aren't used anymore. They were useful way back in the day when a user could only belong to one group at a time.

to remove a user from a group, just delete his name from the corresponding line. There are pretty GUI tools to do it, too.

Okay, thx. I have a removeable hd formatted in fat, and I share it on my ftpserver, but the thing is, it seems impossible for other users of the same group than the one that mounts it, to use it.
I need a solution to this.

root@Nyarlathotep /export $ ls -l
total 34
drwxrwxr-x 7 anv users 152 2004-07-30 00:07 archive1
drwxrwxr-x 3 anv users 48 2004-07-29 23:04 archive2
drwxr--r-- 4 mattias users 32768 1969-12-31 23:00 storage
drwxrwxr-x 2 anv users 48 2004-07-30 01:15 tmp
root@Nyarlathotep /export $ su mattias
mattias@Nyarlathotep /export $ chmod -R g+rx storage/
mattias@Nyarlathotep /export $ ls -l
total 34
drwxrwxr-x 7 anv users 152 2004-07-30 00:07 archive1
drwxrwxr-x 3 anv users 48 2004-07-29 23:04 archive2
drwxr--r-- 4 mattias users 32768 1969-12-31 23:00 storage
drwxrwxr-x 2 anv users 48 2004-07-30 01:15 tmp
mattias@Nyarlathotep /export $

It simply won't change the access rights to it. I want the user viktor to be able to access the dir storage, but he can't. He can access the other dirs, but not storage.

Any ideas?