osx man page for services

SERVICES(5)						      BSD File Formats Manual						       SERVICES(5)

NAME
     services -- service name data base

DESCRIPTION
     The services file contains information regarding the known services available in the DARPA Internet.  For each service a single line should
     be present with the following information:

	   official service name
	   port number
	   protocol name
	   aliases

     Items are separated by any number of blanks and/or tab characters.  The port number and protocol name are considered a single item; a ``/''
     is used to separate the port and protocol (e.g. ``512/tcp'').  A ``#'' indicates the beginning of a comment; subsequent characters up to the
     end of the line are not interpreted by the routines which search the file.

     Service names may contain any printable character other than a field delimiter, newline, or comment character.

INTERACTION WITH DIRECTORY SERVICES
     Processes generally find service records using one of the getservent(3) family of functions, or using getaddrinfo(3).  On Mac OS X, these
     functions interact with the DirectoryService(8) daemon, which reads the /etc/services file as well as searching other directory information
     services to determine service name, protocol, and port information.

FILES
     /etc/services

SEE ALSO
     getservent(3), getaddrinfo(3), DirectoryService(8)

HISTORY
     The services file format appeared in 4.2BSD.

4.2 Berkeley Distribution					   June 5, 1993 					 4.2 Berkeley Distribution