'\" t
.\"     Title: chgpasswd
.\"    Author: Thomas K\(/loczko <kloczek@pld.org.pl>
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 30.07.2026
.\"    Manual: System Management Commands
.\"    Source: shadow-utils 4.20.0
.\"  Language: German
.\"
.TH "CHGPASSWD" "8" "30.07.2026" "shadow\-utils 4\&.20\&.0" "System Management Commands"
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.SH "NAME"
chgpasswd \- aktualisiert Gruppenpassw\(:orter im Stapel\-Modus
.SH "\(:UBERSICHT"
.HP \w'\fBchgpasswd\fR\ 'u
\fBchgpasswd\fR [\fIoptions\fR]
.SH "BESCHREIBUNG"
.PP
The
\fBchgpasswd\fR
command reads a list of group name and password pairs from standard input and uses this information to update a set of existing groups\&. Each line is of the format:
.PP
\fIgroup_name\fR:\fIpassword\fR
.PP
By default the supplied password must be in clear\-text, and is encrypted by
\fBchgpasswd\fR\&.
.PP
The default encryption algorithm can be defined for the system with the
\fBENCRYPT_METHOD\fR
variable of
/etc/login\&.defs, and can be overwritten with the
\fB\-e\fR
or
\fB\-c\fR
options\&.
.PP
Dieser Befehl ist f\(:ur weitreichende Systeme gedacht, bei denenviele Passw\(:orter gleichzeitig aktualisiert werden m\(:ussen\&.
.SH "OPTIONEN"
.PP
The options which apply to the
\fBchgpasswd\fR
command are:
.PP
\fB\-c\fR, \fB\-\-crypt\-method\fR
.RS 4
definiert die Methode, mit der die Passw\(:orter verschl\(:usselt werden\&.
.sp
The available methods are
\fISHA256\fR,
\fISHA512\fR,
\fIYESCRYPT\fR
and
\fINONE\fR
if your libc supports these methods\&.
.RE
.PP
\fB\-e\fR, \fB\-\-encrypted\fR
.RS 4
Passw\(:orter werden verschl\(:usselt geliefert\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
zeigt die Hilfe an und beendet das Programm\&.
.RE
.PP
\fB\-R\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\-s\fR, \fB\-\-sha\-rounds\fR
.RS 4
legt die Anzahl von Runden beim Verschl\(:usseln von Passw\(:ortern fest\&.
.sp
You can only use this option with crypt method:
\fISHA256\fR
\fISHA512\fR
\fIYESCRYPT\fR
.sp
By default, the number of rounds for SHA256 or SHA512 is defined by the SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in
/etc/login\&.defs\&.
.sp
A minimal value of 1000 and a maximal value of 999,999,999 will be enforced for SHA256 and SHA512\&. The default number of rounds is 5000\&.
.sp
By default, the number of rounds for YESCRYPT is defined by the YESCRYPT_COST_FACTOR in
/etc/login\&.defs\&.
.sp
A minimal value of 1 and a maximal value of 11 will be enforced for YESCRYPT\&. The default number of rounds is 5\&.
.RE
.SH "WARNUNGEN"
.PP
Achten Sie darauf, dass die Zugriffsrechte der unverschl\(:usselten Datei beziehungsweise
\fBUMASK\fR
ausschlie\(ssen, dass andere Benutzer sie lesen k\(:onnen\&.
.PP
Sie sollten darauf achten, dass Passw\(:orter und Verschl\(:usselungsmethode in Einklang mit der Passwortrichtlinie des Systems stehen\&.
.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
.PP
\fBYESCRYPT_COST_FACTOR\fR (number)
.RS 4
When
\fBENCRYPT_METHOD\fR
is set to
\fIYESCRYPT\fR, this defines the cost factor used by the encryption algorithm by default (when the cost factor is not specified on the command line)\&.
.sp
With a high cost factor, it is more difficult to brute force the password\&. But note also that more CPU resources will be needed to authenticate users\&.
.sp
The value must be inside the 1\-11 range\&.
.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
.PP
/etc/login\&.defs
.RS 4
konfiguriert die Shadow\-Hilfsprogramme\&.
.RE
.SH "SIEHE AUCH"
.PP
\fBgpasswd\fR(1),
\fBgroupadd\fR(8),
\fBlogin.defs\fR(5)\&.