CHPASSWD(8) System Management Commands CHPASSWD(8)

chpasswd - aktualisiert Passwörter im Stapel-Modus


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.

Dieser Befehl ist für weitreichende Systeme gedacht, bei denenviele Passwörter gleichzeitig aktualisiert werden müssen.

The options which apply to the chpasswd command are:

-c, --crypt-method METHOD

definiert die Methode, mit der die Passwörter verschlüsselt werden.

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

Standardmäßig verschlüsselt PAM die Passwörter.

-e, --encrypted

Passwörter werden verschlüsselt geliefert.

-h, --help

zeigt die Hilfe an und beendet das Programm.

-m, --md5

Zur Verschlüsselung MD5 anstelle von DES verwenden, wenn die Passwörter unverschlüsselt geliefert werden.

-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

legt die Anzahl von Runden beim Verschlüsseln von Passwörtern fest.

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.

Achten Sie darauf, dass die Zugriffsrechte der unverschlüsselten Datei beziehungsweise UMASK ausschließen, dass andere Benutzer sie lesen können.

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


Informationen zu den Benutzerkonten


geschützte Informationen zu den Benutzerkonten


konfiguriert die Shadow-Hilfsprogramme.


PAM configuration for chpasswd.

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

01.04.2024 shadow-utils 4.15.1