What would cause this output

shanenin · 02-14-2004, 03:31 PM

what would cause this output. If it matters I am tryingto configure my LFS system.

Code:

[root@marsala /etc]# su - shane
id: cannot find name for group ID 100
[shane@marsala ~]$

AMMullan · 02-14-2004, 03:43 PM

Ummm from what I can see it appears that a group that "shane" belongs to has been deleted...

shanenin · 02-14-2004, 05:56 PM

I think I need a basic understanding of how users and groups are set up.

AMMullan · 02-14-2004, 06:21 PM

K i'm not an expert but this is what I know:

First of all, root ALWAYS has a UID of 0.

When u add a user they get a UID (User ID) i.e. 500
You are also part of a group - as a default its your username. (GID might be also be 500)
That information is all stored in /etc/passwd along with your home directory and encrypted password.
When you logon or a program needs to authenticate you it checks /etc/passwd for an entry and when you enter a password it is encrypted and compared to that of the /etc/passwd entry.

Thats basically it, file permissions are basic, they are based on username and pasword but alsoo permission bits (i.e. you might do an ls -l foo and get get the following)

Code:

[ammullan@daemon ~]$ ls -l | grep foo
-rwxrwxr-x    1 ammullan ammullan    11954 Feb 14 20:59 foo

The -rwxrwxr-x is read, write and execute permissions. They are broken down into 3 block groups (i.e. in this example foo can be read, written to and executed by user and group and can be read and executed by all)... The 1st bit will have a d if it's a directory etc.

Hope that helps a bit

(If ya wanna know any more let me know)

shanenin · 02-14-2004, 06:31 PM

thanks for all of your help, this gives me somthing to work from.

AMMullan · 02-14-2004, 06:57 PM

No problems

Also, if you use id it'll show u what your UID and GID is (you can also do id root to find out root's etc)

shanenin · 02-14-2004, 06:57 PM

I kind of tracked the problem down to /etc/bashrc . If I change the name of that file I no longer get that output anymore.

AMMullan · 02-14-2004, 07:01 PM

Ummmm you knmow thats where all your system aliases and bash info is stored aye?

shanenin · 02-14-2004, 07:03 PM

I am not leaving it that way(/etc/bashrc2), I just thought it was interesting that that made a difference.

AMMullan · 02-14-2004, 07:09 PM

K just looking at the file - check this line:

Code:

if [ "`id -gn`" = "`id -un`" -a `id -u` -gt 99 ]; then
        umask 002
else
        umask 022
fi

This is checking your UID, GID and makes sure that your UID is greater than 99 - try this:

usermod -U shane -g shane

If you get an error try:

groupadd shane
usermod -U shane -g shane

AMMullan · 02-14-2004, 07:12 PM

Actually just tried that (thought it would work) but it doesn't... did you try teh id shane?

shanenin · 02-14-2004, 07:39 PM

I added this line to /etc/group(advice from a different forum)

shane:x:100:

that fixed it. That leads me to another question: how come my gentoo system works fine without that line in /etc/group

shanenin · 02-14-2004, 07:53 PM

thanks for all of your help

AMMullan · 02-14-2004, 08:22 PM

Quote:

That leads me to another question: how come my gentoo system works fine without that line in /etc/group

Not sure, but without a group the user is a nobody (less than that even as there's a nobody group lol)

Basically, your GID says what permissions you have as a user, without that i'd be surprised if you can do much