| || specifies a user whose passwd(5) entry will be used as a template to create the session environment if the supplied username does not exist in local password database. The user will be authenticated with the supplied username and password, but his credentials to the system will be presented as the ones for username, i.e., his login class, home directory, resource limits, etc. will be set to ones defined for username. |
If this option is omitted, and there is no username in the system databases equal to the supplied one (as determined by call to getpwnam(3)), the authentication will fail.