Hmmm, I think it's time you stopped thinking as though this is windows. You should be able to log-into each Linux machine remotely and make all the appropriate changes. This actually becomes much easier once /home is shared between the machines, you might have to go to each machine individually and make sure SSH is turned on, and maybe make sure each starts the SSH service after boot.

Set up NIS on the server before you share /home. This is easy, you can add accounts as you like for each of the users, and pinch their password string from their local /etc/shadow file. You need to install the ypserv module, edit /etc/yp.conf and /etc/ypbind.conf to suit your network and run make in /var/yp.

Add the /home partition, and any others you want to provide, in /etc/exports - see the man page for this file for detailed help, but you want a line that looks a bit like this (your IP address may be different):

and restart the NFS server service.

Log on to each Linux machine in turn, and copy the contents of each users' /home directory into the /home on the server. Map over any permissions - you may have a UID or GID conflict if they're using local /etc/passwd and /etc/group files. You can fix this by making sure file ownerships are switched with chgrp and chown as you're copying them in. This is why you create the accounts first.

When this is all done (it'll take a bit of time - you may wish to do one computer at a time, rather that each step for all machines) you can log onto each machine, make sure the ypbind and yp-tools modules are installed, edit /etc/yp.conf and run authconfig to turn the thing on. Make sure you set the YP service to start in their runlevel. Test the NIS system is working with 'ypcat passwd'.

Next log on to each machine, make an entry in /etc/fstab to mount the exported filesystems from the server. The manpage for fstab really helps here, but a line should look summat like this:

<servername>:/home   /home  nfs  defaults,rsize=8192,wsize=8129,timeo=14,intr,tcp  0 0
then mount /home with 'mount /home' on that machine.

Test that you're able to read the mounted filesystem by browsing it. Double check that everything is set to start in the right runlevel on that machine and do a reboot (remotely). When it's back up, test that the mount worked OK, and that you can log in as any of the network users on that machine (i.e. that NIS is working fine).

This is quite a long-winded operation; it's much simpler if you do this from install time rather than after the system has been working for some time. I suggest that you work your way slowly through the lan one machine at a time, and do it all remotely - i.e. from a console on the server. The actual changes will take you five or ten minutes to complete per machine, but copying the /home for each user will be the slow bit if they've got lots of junk.