Any of three fields can be empty, in which case it
signifies a ``wild card.'' Thus
universal (,,)
defines a group to which everyone belongs. Field names that begin with something other than a letter, digit, or underscore (such as ``-'') work in precisely the opposite fashion. For example, consider the following entries:
justmachines (analytic,-,sun) justpeople (-,babbage,sun)The machine, analytic, belongs to the group, justmachines, in the domain, sun, but no users belong to it. Similarly, the user, babbage, belongs to the group, justpeople, in the domain, sun, but no machines belong to it.
Network groups are contained in the Network Information Service
and are accessed through these files:
/etc/yp/domainname/netgroup.dir
/etc/yp/domainname/netgroup.pag
/etc/yp/domainname/netgrp.usr.dir
/etc/yp/domainname/netgrp.usr.pag
/etc/yp/domainname/netgrp.hst.dir
/etc/yp/domainname/netgrp.hst.pag
These files can be created from /etc/netgroup using
makedbm(NADM).