The /etc/passwd and /etc/group Files and the Registry

You should maintain standard versions of the /etc/passwd and /etc/group files on local machines to ensure compatibility with UNIX programs. To keep the /etc/passwd and /etc/group files consistent with the registry database, use the passwd_export command. It is advisable to run passwd_export on a regular basis, preferably using cron. (See Performing Routine Maintenance for details on passwd_export.)

Note: Unlike standard UNIX behavior, the /etc/passwd and /etc/group files are not used for local login if a security server is unavailable. Instead, the local registry (described in The Local Registry) is used. The /etc/passwd and /etc/group file are maintained only for compatibility with UNIX programs that require their existence.