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CHPASSWD(8) System Management Commands CHPASSWD(8)


chpasswd - Mettre à jour des mots de passe par lot


chpasswd [options]


The chpasswd 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:


By default the passwords must be supplied in clear-text, and are encrypted by chpasswd. Also the password age will be updated, if present.

By default, passwords are encrypted by PAM, but (even if not recommended) you can select a different encryption method with the -e, -m, or -c options.

Except when PAM is used to encrypt the passwords, chpasswd first updates all the passwords in memory, and then commits all the changes to disk if no errors occurred for any user.

When PAM is used to encrypt the passwords (and update the passwords in the system database) then if a password cannot be updated chpasswd continues updating the passwords of the next users, and will return an error code on exit.

Cette commande est destinée aux gros systèmes pour lesquels un nombre importants de comptes sont créés en une seule fois.


The options which apply to the chpasswd command are:

-c, --crypt-method METHOD

Utiliser la méthode précisée pour chiffrer les mots de passe.

The available methods are DES, MD5, SHA256, SHA512, YESCRYPT and NONE if your libc supports these methods.

Par défaut, PAM est utilisé pour chiffrer les mots de passe.

-e, --encrypted

Indiquer que les mots de passe fournis sont chiffrés.

-h, --help

Afficher un message d'aide et quitter.

-m, --md5

Permettre d'utiliser le chiffrement MD5, plutôt que DES, lorsque les mots de passe fournis ne sont pas chiffrés.

-R, --root CHROOT_DIR

Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory. Only absolute paths are supported.

-P, --prefix PREFIX_DIR

Apply changes to configuration files under the root filesystem found under the directory PREFIX_DIR. 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.

-s, --sha-rounds ROUNDS

Utiliser le nombre de rounds précisé pour chiffrer les mots de passe.

You can only use this option with crypt method: SHA256 SHA512 YESCRYPT

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.

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.

By default, the number of rounds for YESCRYPT is defined by the YESCRYPT_COST_FACTOR in /etc/login.defs.

A minimal value of 1 and a maximal value of 11 will be enforced for YESCRYPT. The default number of rounds is 5.


Pensez à configurer les permissions ou umask afin d'empêcher la lecture des fichiers non chiffrés par les d'autres utilisateurs.


The following configuration variables in /etc/login.defs change the behavior of this tool:



Informations sur les comptes des utilisateurs.


Informations sécurisées sur les comptes utilisateurs.


Configuration de la suite des mots de passe cachés « shadow password ».


PAM configuration for chpasswd.


passwd(1), newusers(8), login.defs(5), useradd(8).

07/07/2024 shadow-utils 4.15.3