[CentOS] preparing to migrating to new system

On Sat, Dec 25, 2010 at 2:36 AM, Benjamin Smith
<lists at benjamindsmith.com> wrote:
>> What is the most sensible or correct way to migrate ALL the users to the
>> new system?
>> Way in the past is was just perhaps copy the /etc/passwd file but I know
>> thats not the case anymore.
>> how do I easily recreate their account names etc... on the new machine.
>
> When transitioning mail servers, I've always done this by writing a perl/PHP
> script to parse the passwd files and create "user only" passwd/shadow, group,
> gshadow, etc. files and then append those to the new system. For most recent RH
> based distros, users start at either 100 or 500, with the lower numbers
> reserved for system/daemon accounts. Then you can copy over the emails with
> rsync with the numeric IDs option set and it will all "just work".

Beware the user "nobody", and a lot of carelessly built vendor
software that adds a user, but fails to make that user a "system"
user. I just ran into this headlong with the latest NX software from
www.nomachine.com.