Let me preface this by saying that im admittedly a total newbie and in no way would claim to be anything other then that--course that would explain why im posting here.
Anyway I am curious to know what would happen if I edited the uid's in the /etc/passwd file so that multiple users had the same uid.

For example:
greg:x:502:503::/home/greg:/bin/bash
james:x:503:503::/home/james:/bin/bash
becomes:
greg:x:502:503::/home/greg:/bin/bash
james:x:502:503::/home/james:/bin/bash
Is my computer going to ignite into a flaming ball :0?

And while im at it id like to know if a uid of say 200 would have some sort of differing access rights as someone with say 500 uid.

I appreciate the most newbized response I can get, as I again I am no expert at this at any level.

I think that the system would treat them as the same user if they had the same number.

As for the difference between 200 and 500, I think the only one that makes a difference is root.... which has 0.

I was waiting for someone else to respond with your answer Adam. I second his thoughts

A name is something for your eyes, so you don't go blind looking at numbers. I think the number (uid/gid) is your representation to linux as to what user/group it is.

As for the numbers being anything...

It's not going to be a big problem, as long as the uid is not already assigned to something/someone. The main thing on that is that "usually" your users (depending on your distro) are above 500. It doesn't mean that they will acquire super powers, and mind control if you place them lower, it's just that usually the lower numbers are reserved for the non-existent "service" users.

The exception, as noted by Adam, is root's uid, 0.

If you want your computer to have multiple users, but all of them have the same amount of access to each other's files (full access) then I would guess this would be the way to do it. Otherwise, you will probably be better off leaving them as seperate uid's.

*Note:
This is the same answer as Adam just expanded a bit more

Cool

This will work; however, it makes things a little difficult to track who did what on your system. I worked at place where the previous admin setup the accounts like this. It worked fine until one user created files that the others were not supposed to have access to. I had to go back and separate all the accounts to unique UIDs and put them in groups.

Thank you all for such great responses, god knows how many books I would have had to browse through for the answer to this question. You all saved me alot of time and trouble.

Actually I did want a group of people to have access to the same files, so far I have them all using separate Uids, but they are all in the same group. The owner of the shared directory that everyone is supposed to have full access to is the group. Is this how its supposed to be?

Anyway thank you all again for the help youve provided me. Ill definately be posting again. (And thank you for the non-technical response it helps alot )

That sounds good to me (but then again, I haven't really gotten around to playing around with multiple users and groups).... does it work o.k.?

congrat's on finding LQ.... it's a really nice place to get help (as you've just found out)