---
name: "revnetgroup"
section: "8"
platform: "linux"
package: "ypserv"
version: "4.2-2+b2"
release: "Debian 13 (Trixie)"
platforms: ["linux", "freebsd", "openbsd"]
url: "https://new.carta.tech/revnetgroup"
---

# revnetgroup(8)

generate reverse netgroup data

## NAME

revnetgroup - generate reverse netgroup data

## SYNOPSIS

**/usr/lib/yp/revnetgroup** \[-u \| -h\]

## DESCRIPTION

**Revnetgroup** processes the standard input in [**netgroup**(5)](/netgroup/5.md) 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 NIS maps. These reverse netgroup maps are used to help speed up netgroup lookups, particularly for the **innetgr()** library function.

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

## 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.

## FILES

/var/yp/Makefile

The Makefile to build the NIS databases.

/etc/netgroup

The default netgroup database file. This file is most often found only on the NIS master server.

## SEE ALSO

[**getnetgrent**(3)](/getnetgrent/3.md), [**netgroup**(5)](/netgroup/5.md),

## AUTHOR

**revnetgroup** was written by Thorsten Kukuk \<kukuk@linux-nis.org\>.