'\" t .\" Title: chpasswd .\" Author: Julianne Frances Haugh .\" Generator: DocBook XSL Stylesheets vsnapshot .\" Date: 02.07.2024 .\" Manual: System Management Commands .\" Source: shadow-utils 4.16.0 .\" Language: German .\" .TH "CHPASSWD" "8" "02.07.2024" "shadow\-utils 4\&.16\&.0" "System Management Commands" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" chpasswd \- aktualisiert Passw\(:orter im Stapel\-Modus .SH "\(:UBERSICHT" .HP \w'\fBchpasswd\fR\ 'u \fBchpasswd\fR [\fIoptions\fR] .SH "BESCHREIBUNG" .PP The \fBchpasswd\fR command reads a list of user name and password pairs from standard input and uses this information to update a group of existing users\&. Each line is of the format: .PP \fIuser_name\fR:\fIpassword\fR .PP By default the passwords must be supplied in clear\-text, and are encrypted by \fBchpasswd\fR\&. Also the password age will be updated, if present\&. .PP By default, passwords are encrypted by PAM, but (even if not recommended) you can select a different encryption method with the \fB\-e\fR, \fB\-m\fR, or \fB\-c\fR options\&. .PP Except when PAM is used to encrypt the passwords, \fBchpasswd\fR first updates all the passwords in memory, and then commits all the changes to disk if no errors occurred for any user\&. .PP When PAM is used to encrypt the passwords (and update the passwords in the system database) then if a password cannot be updated \fBchpasswd\fR continues updating the passwords of the next users, and will return an error code on exit\&. .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 \fBchpasswd\fR command are: .PP \fB\-c\fR, \fB\-\-crypt\-method\fR\ \&\fIMETHOD\fR .RS 4 definiert die Methode, mit der die Passw\(:orter verschl\(:usselt werden\&. .sp The available methods are \fIDES\fR, \fIMD5\fR, \fISHA256\fR, \fISHA512\fR, \fIYESCRYPT\fR and \fINONE\fR if your libc supports these methods\&. .sp Standardm\(:a\(ssig verschl\(:usselt PAM die Passw\(:orter\&. .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\-m\fR, \fB\-\-md5\fR .RS 4 Zur Verschl\(:usselung MD5 anstelle von DES verwenden, wenn die Passw\(:orter unverschl\(:usselt geliefert werden\&. .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\&. .RE .PP \fB\-P\fR, \fB\-\-prefix\fR\ \&\fIPREFIX_DIR\fR .RS 4 Apply changes to configuration files under the root filesystem found under the directory \fIPREFIX_DIR\fR\&. This option does not chroot and is intended for preparing a cross\-compilation target\&. Some limitations: NIS and LDAP users/groups are not verified\&. PAM authentication is using the host files\&. No SELINUX support\&. .RE .PP \fB\-s\fR, \fB\-\-sha\-rounds\fR\ \&\fIROUNDS\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\&. .SH "KONFIGURATION" .PP The following configuration variables in /etc/login\&.defs change the behavior of this tool: .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 The values must be inside the 1000\-999,999,999 range\&. .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/passwd .RS 4 Informationen zu den Benutzerkonten .RE .PP /etc/shadow .RS 4 gesch\(:utzte Informationen zu den Benutzerkonten .RE .PP /etc/login\&.defs .RS 4 konfiguriert die Shadow\-Hilfsprogramme\&. .RE .PP /etc/pam\&.d/chpasswd .RS 4 PAM configuration for \fBchpasswd\fR\&. .RE .SH "SIEHE AUCH" .PP \fBpasswd\fR(1), \fBnewusers\fR(8), \fBlogin.defs\fR(5), \fBuseradd\fR(8)\&.