File permissions for shared home directories?

[Jef Driesen]

Hi,

I have a NAS server with two unix accounts, named "me" and "wife". Each account 
has its own home directory, which are exported over NFS. So far no problem.

But I also have a common laptop which only has a single unix account which is 
shared between the two persons. If I give the laptop user the same UID/GID as 
the "me" account on the NAS, I can access my personal files. But how do I make 
sure I can also access the files from the "wife" account?

I'm looking for a solution that is reasonable secure. It's fine if the "me" and 
"wife" account can access each others file, but other accounts should not have 
access.

Jef