Syntax of the nsswitch.conf File  

Each line in the /etc/nsswitch.conf file has the following syntax :

lookup_type name_service [status=action status=action ...] name_service ...

If you include any status=action pairs after a name service, the square brackets are required.

lookup_type		The type of information to be looked up. The supported keywords and the information types they represent are listed in Types of Lookups Controlled by the Name Service Switch. These keywords are case-sensitive.
name_service		One of the following name services to use for the type of information in the lookup_type field. These keywords must be in lowercase. files   Files in the /etc directory on the local host (/etc/hosts, /etc/services, and so on). nis   Network Information Service (NIS). dns   Domain Name System (DNS), which is implemented by Berkeley Internet Name Domain (BIND) on HP-UX. See the Installing and Administering Internet Services manual for more information. The dns keyword may be used only on the line beginning with hosts.
status		One of the following statuses returned by a name service query. These values may be entered in uppercase or lowercase. SUCCESS   The lookup was successful, and the requested information was found. NOTFOUND   The name service returned a response, but the requested data was not in its database. UNAVAIL   The name service is not configured. TRYAGAIN   The name service was busy and the request timed out. This value is returned only by DNS.
action		The action to take based on the status of the name service query. The following values may be entered in uppercase or lowercase. continue   Try the next name service in the list. return   End the lookup and return control to the calling process without consulting the next name service in the list.

If a line beginning with one of the lookup_types does not exist in the /etc/nsswitch.conf file, the default Name Service Switch configuration for that type of information is used. If the /etc/nsswitch.conf file does not exist, the default configuration is used for every type of information. The default Name Service Switch configuration is described in Default Configuration.