'\" t .\" Title: chgpasswd .\" Author: Thomas K\(/loczko .\" Generator: DocBook XSL Stylesheets vsnapshot .\" Date: 30/07/2026 .\" Manual: System Management Commands .\" Source: shadow-utils 4.20.0 .\" Language: French .\" .TH "CHGPASSWD" "8" "30/07/2026" "shadow\-utils 4\&.20\&.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 "NOM" chgpasswd \- Mettre \(`a jour par lot des mots de passe des groupes .SH "SYNOPSIS" .HP \w'\fBchgpasswd\fR\ 'u \fBchgpasswd\fR [\fIoptions\fR] .SH "DESCRIPTION" .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 Cette commande est destin\('ee aux gros syst\(`emes pour lesquels un nombre importants de comptes sont cr\('e\('es en une seule fois\&. .SH "OPTIONS" .PP The options which apply to the \fBchgpasswd\fR command are: .PP \fB\-c\fR, \fB\-\-crypt\-method\fR .RS 4 Utiliser la m\('ethode pr\('ecis\('ee pour chiffrer les mots de passe\&. .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 Indiquer que les mots de passe fournis sont chiffr\('es\&. .RE .PP \fB\-h\fR, \fB\-\-help\fR .RS 4 Afficher un message d\*(Aqaide et quitter\&. .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 Utiliser le nombre de rounds pr\('ecis\('e pour chiffrer les mots de passe\&. .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 "AVERTISSEMENTS" .PP Pensez \(`a configurer les permissions ou umask afin d\*(Aqemp\(^echer la lecture des fichiers non chiffr\('es par les d\*(Aqautres utilisateurs\&. .PP Vous devez vous assurer que les mots de passe et la m\('ethode de chiffrement respectent la politique de mot de passe du syst\(`eme\&. .SH "CONFIGURATION" .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 La valeur par d\('efaut est 0, ce qui signifie qu\*(Aqil n\*(Aqy a pas de limites pour le nombre de membres dans un groupe\&. .sp Cette fonctionnalit\('e (groupe d\('ecoup\('e) permet de limiter la longueur des lignes dans le fichier de groupes\&. Ceci est utile pour s\*(Aqassurer que les lignes pour les groupes NIS ne sont pas plus grandes que 1024 caract\(`eres\&. .sp Si vous avez besoin de configurer cette limite, vous pouvez utiliser 25\&. .sp Remarque\ \&: les groupes d\('ecoup\('es ne sont peut\-\(^etre pas pris en charge par tous les outils (m\(^eme dans la suite d\*(Aqoutils Shadow)\&. Vous ne devriez pas utiliser cette variable, sauf si vous en avez vraiment besoin\&. .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 Les valeurs doivent \(^etre comprises dans l\*(Aqintervalle 1\ \&000\ \&\-\ \&999\ \&999\ \&999\&. .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 "FICHIERS" .PP /etc/group .RS 4 Informations sur les groupes\&. .RE .PP /etc/gshadow .RS 4 Informations s\('ecuris\('ees sur les groupes\&. .RE .PP /etc/login\&.defs .RS 4 Configuration de la suite des mots de passe cach\('es \(Fo\ \&shadow password\ \&\(Fc\&. .RE .SH "VOIR AUSSI" .PP \fBgpasswd\fR(1), \fBgroupadd\fR(8), \fBlogin.defs\fR(5)\&.