2 .\" Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
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31 .\" $FreeBSD: src/libexec/revnetgroup/revnetgroup.8,v 1.7.2.4 2002/08/15 18:53:16 schweikh Exp $
38 .Nd "generate reverse netgroup data"
42 .Op Fl f Ar netgroup_file
45 .Op Fl f Ar netgroup_file
48 processes the contents of a file in
50 format into what is called
52 form. That is, where the original file shows
53 netgroup memberships in terms of which members reside in a particular
54 group, the reverse netgroup format specifies what groups are associated
55 with a particular member. This information is used to generate the
60 maps. These reverse netgroup maps are used to help speed up
61 netgroup lookups, particularly for the
65 For example, the standard
67 file may list a netgroup and a list of its members. Here, the
68 netgroup is considered the
70 and the member names are the
72 By contrast, the reverse
74 database lists each unique
75 member as the key and the netgroups to which the members belong become
76 the data. Separate databases are created to hold information pertaining
77 to users and hosts; this allows netgroup username lookups
78 and netgroup hostname lookups to be performed using independent keyspaces.
80 By constructing these reverse netgroup databases (and the corresponding
84 library functions are spared from having to work out the dependencies
85 themselves on the fly. This is important on networks with large numbers
86 of users and hosts, since it can take a considerable amount of time
87 to process very large netgroup databases.
91 command prints its results on the standard output. It is usually called
100 command supports the following options:
101 .Bl -tag -width indent
105 output; only username information in the
106 original netgroup file is processed.
110 output; only hostname information in the
111 original netgroup file is processed. (Note at least one of the
115 flags must be specified.)
116 .It Op Fl f Ar netgroup_file
121 as its default input file. The
123 flag allows the user to specify an alternate input file. Specifying ``-''
124 as the input file causes
126 to read from the standard input.
129 .Bl -tag -width /var/yp/Makefile -compact
130 .It Pa /var/yp/Makefile
131 the Makefile that calls
139 the default netgroup database file. This file is most often found
150 .An Bill Paul Aq Mt wpaul@ctr.columbia.edu