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OpenDarwin 7.2.1 - man page for revnetgroup (opendarwin section 8)

REVNETGROUP(8)			   BSD System Manager's Manual			   REVNETGROUP(8)

     revnetgroup -- generate reverse netgroup data

     revnetgroup -u -h [-f netgroup_file]

     revnetgroup processes the contents of a file in netgroup(5) format into what is called
     reverse netgroup form. That is, where the original file shows netgroup memberships in terms
     of which members reside in a particular group, the reverse netgroup format specifies what
     groups are associated with a particular member. This information is used to generate the
     netgroup.byuser and netgroup.byhosts YP maps. These reverse netgroup maps are used to help
     speed up netgroup lookups, particularly for the innetgr() library function.

     For example, the standard /etc/netgroup file may list a netgroup and a list of its members.
     Here, the netgroup is considered the key and the member names are the data.  By contrast,
     the reverse netgroup.byusers database lists each unique member as the key and the netgroups
     to which the members belong become the data. Seperate databases are created to hold informa-
     tion pertaining to users and hosts; this allows netgroup username lookups and netgroup host-
     name lookups to be performed using independent keyspaces.

     By constructing these reverse netgroup databases (and the corresponding YP maps) in advance,
     the getnetgrent(3) library functions are spared from having to work out the dependencies
     themselves on the fly. This is important on networks with large numbers of users and hosts,
     since it can take a considerable amount of time to process very large netgroup databases.

     The revnetgroup command prints its results on the standard output. It is usually called only
     by /var/yp/<domain>/Makefile when rebuilding the YP netgroup maps.

     The revnetgroup command supports the following options:

     -u    Generate netgroup.byuser output; only username information in the original netgroup
	   file is processed.

     -h    Generate netgroup.byhost output; only hostname information in the original netgroup
	   file is processed. (Note at least one of the -u or -h flags must be specified.)

     [-f netgroup_file]
	   The revnetgroup command uses /etc/netgroup as its default input file. The -f flag
	   allows the user to specify an alternate input file. Specifying ``-'' as the input file
	   causes revnetgroup to read from the standard input.

     /var/yp/<domain>Makefile	       The Makefile that calls makedbm and revnetgroup to build
				       the YP databases.
     /etc/netgroup		       The default netgroup database file. This file is most
				       often found only on the YP master server.

     getnetgrent(3), yp(8), netgroup(5), makedbm(8)

     Bill Paul <wpaul@ctr.columbia.edu>

BSD					 October 24, 1995				      BSD

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