osx man page for domainname

DOMAINNAME(1)						    BSD General Commands Manual 					     DOMAINNAME(1)

NAME
     domainname -- set or print name of current YP/NIS domain

SYNOPSIS
     domainname [ypdomain]

DESCRIPTION
     The domainname utility prints the name of the current YP/NIS domain.  The super-user can set the domain name by supplying an argument; this
     is usually done at startup by specifying a domain name in the contents of the file /etc/defaultdomain.

NOTES
     The YP/NIS (formerly ``Yellow Pages'' but renamed for legal reasons) domain name does not necessarily have anything to do with the Domain
     Name System domain name, although they are often set equal for administrative convenience.

SEE ALSO
     getdomainname(3)

HISTORY
     The domainname command appeared in FreeBSD 1.1, based on a similar command in SunOS.

BSD
								September 18, 1994							       BSD