'\" t
.\"     Title: gpasswd
.\"    Author: Rafal Maszkowski
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 30.07.2026
.\"    Manual: User Commands
.\"    Source: shadow-utils 4.20.0
.\"  Language: German
.\"
.TH "GPASSWD" "1" "30.07.2026" "shadow\-utils 4\&.20\&.0" "User Commands"
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.SH "NAME"
gpasswd \- administer /etc/group and /etc/gshadow
.SH "\(:UBERSICHT"
.HP \w'\fBgpasswd\fR\ 'u
\fBgpasswd\fR [\fIoption\fR] \fIgroup\fR
.SH "BESCHREIBUNG"
.PP
The
\fBgpasswd\fR
command is used to administer
/etc/group, and /etc/gshadow\&. Every group can have
administrators,
members and a password\&.
.PP
System administrators can use the
\fB\-A\fR
option to define group administrator(s) and the
\fB\-M\fR
option to define members\&. They have all rights of group administrators and members\&.
.PP
\fBgpasswd\fR
called by
a group administrator
with a group name only prompts for the new password of the
\fIgroup\fR\&.
.PP
If a password is set the members can still use
\fBnewgrp\fR(1)
without a password, and non\-members must supply the password\&.
.SS "Hinweise zu Gruppenpassw\(:ortern"
.PP
Gruppenpassw\(:orter bergen ein Sicherheitsrisiko, da mehrere Personen das Passwort kennen\&. Dennoch sind Gruppen ein n\(:utzliches Mittel f\(:ur die Zusammenarbeit zwischen Benutzern\&.
.SH "OPTIONEN"
.PP
Except for the
\fB\-A\fR
and
\fB\-M\fR
options, the options cannot be combined\&.
.PP
The options which apply to the
\fBgpasswd\fR
command are:
.PP
\fB\-a\fR, \fB\-\-add\fR\ \&\fIuser\fR
.RS 4
Add the
\fIuser\fR
to the named
\fIgroup\fR\&.
.RE
.PP
\fB\-d\fR, \fB\-\-delete\fR\ \&\fIuser\fR
.RS 4
Remove the
\fIuser\fR
from the named
\fIgroup\fR\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
zeigt die Hilfe an und beendet das Programm\&.
.RE
.PP
\fB\-Q\fR, \fB\-\-root\fR\ \&\fICHROOT_DIR\fR
.RS 4
Apply changes in the
\fICHROOT_DIR\fR
directory and use the configuration files from the
\fICHROOT_DIR\fR
directory\&. Only absolute paths are supported\&. No SELINUX support\&.
.RE
.PP
\fB\-r\fR, \fB\-\-remove\-password\fR
.RS 4
Remove the password from the named
\fIgroup\fR\&. The group password will be empty\&. Only group members will be allowed to use
\fBnewgrp\fR
to join the named
\fIgroup\fR\&.
.RE
.PP
\fB\-R\fR, \fB\-\-restrict\fR
.RS 4
Restrict the access to the named
\fIgroup\fR\&. The group password is set to "!"\&. Only group members with a password will be allowed to use
\fBnewgrp\fR
to join the named
\fIgroup\fR\&.
.RE
.PP
\fB\-A\fR, \fB\-\-administrators\fR\ \&\fIuser\fR,\&.\&.\&.
.RS 4
definiert eine Liste von Benutzern als Gruppenverwalter
.RE
.PP
\fB\-M\fR, \fB\-\-members\fR\ \&\fIuser\fR,\&.\&.\&.
.RS 4
definiert eine Liste von Benutzern als Gruppenmitglieder
.RE
.SH "WARNUNGEN"
.PP
This tool only operates on the
/etc/group
and /etc/gshadow files\&.
Thus you cannot change any NIS or LDAP group\&. This must be performed on the corresponding server\&.
.SH "KONFIGURATION"
.PP
The following configuration variables in
/etc/login\&.defs
change the behavior of this tool:
.PP
\fBENCRYPT_METHOD\fR (string)
.RS 4
This defines the system default encryption algorithm for encrypting passwords (if no algorithm is specified on the command line)\&.
.sp
It can take one of these values:
\fISHA256\fR,
\fISHA512\fR
(default),
\fIYESCRYPT\fR\&. See
crypt(5)
for recommendations\&.
.sp
Note: this only affects the generation of group passwords\&. The generation of user passwords is done by PAM and subject to the PAM configuration\&. It is recommended to set this variable consistently with the PAM configuration\&.
.sp
History: This variable is used by other programs, which may still default to unsafe algorithms such as DES\&. To avoid using unsafe algorithms, the variable should always be specified\&.
.RE
.PP
\fBMAX_MEMBERS_PER_GROUP\fR (number)
.RS 4
Maximum members per group entry\&. When the maximum is reached, a new group entry (line) is started in
/etc/group
(with the same name, same password, and same GID)\&.
.sp
Der Standardwert ist 0, was bedeutet, dass die Anzahl der Mitglieder einer Gruppe nicht begrenzt ist\&.
.sp
Das Aufteilen von Gruppen erm\(:oglicht es, L\(:angenvorgaben f\(:ur die Zeilen der Gruppendatei einzuhalten\&. Damit kann sichergestellt werden, dass die Zeilen f\(:ur NIS\-Gruppen nicht l\(:anger als 1024 Zeichen sind\&.
.sp
Falls Sie eine solche Begrenzung ben\(:otigen, k\(:onnen Sie 25 verwenden\&.
.sp
Hinweis: Mit aufgeteilten Gruppen k\(:onnen m\(:oglicherweise nicht alle Hilfsprogramme (nicht einmal jene der Shadow\-Programmsammlung) umgehen\&. Sie sollten diese Variable nur setzen, wenn Sie sie wirklich ben\(:otigen\&.
.RE
.PP
\fBSHA_CRYPT_MIN_ROUNDS\fR (number), \fBSHA_CRYPT_MAX_ROUNDS\fR (number)
.RS 4
When
\fBENCRYPT_METHOD\fR
is set to
\fISHA256\fR
or
\fISHA512\fR, this defines the number of SHA rounds used by the encryption algorithm by default (when the number of rounds is not specified on the command line)\&.
.sp
With a lot of rounds, it is more difficult to brute force the password\&. But note also that more CPU resources will be needed to authenticate users\&.
.sp
If not specified, the libc will choose the default number of rounds (5000), which is orders of magnitude too low for modern hardware\&.
.sp
Die Werte m\(:ussen zwischen 1000 und 999\&.999\&.999 liegen\&.
.sp
If only one of the
\fBSHA_CRYPT_MIN_ROUNDS\fR
or
\fBSHA_CRYPT_MAX_ROUNDS\fR
values is set, then this value will be used\&.
.sp
If
\fBSHA_CRYPT_MIN_ROUNDS\fR
>
\fBSHA_CRYPT_MAX_ROUNDS\fR, the highest value will be used\&.
.sp
Note: this only affect the generation of group passwords\&. The generation of user passwords is done by PAM and subject to the PAM configuration\&. It is recommended to set this variable consistently with the PAM configuration\&.
.RE
.SH "DATEIEN"
.PP
/etc/group
.RS 4
Informationen zu den Gruppenkonten
.RE
.PP
/etc/gshadow
.RS 4
gesch\(:utzte Informationen zu den Gruppenkonten
.RE
.SH "SIEHE AUCH"
.PP
\fBnewgrp\fR(1),
\fBgroupadd\fR(8),
\fBgroupdel\fR(8),
\fBgroupmod\fR(8),
\fBgrpck\fR(8),
\fBgroup\fR(5), \fBgshadow\fR(5)\&.