The Name Service Switch (Overview)

At the end of the section, “The Switch File and Password Information”, the following text should be added:

Avoid maintaining multiple repositories for the same user. By maintaining centralized password management in a single repository for each user, you reduce the possibilities of confusion and error. If you choose to maintain multiple repositories per user, update password information by using the passwd -r command.

passwd -r repository

If no repository is specified with the -r option, passwd updates the list of repositories in nsswitch.conf in reverse order.