PWCONV(8)                 System Management Commands                 PWCONV(8)

NOM
       pwconv, pwunconv, grpconv, grpunconv - convert between the system's
       shadowed and plain account files

SYNOPSIS
       pwconv [options]

       pwunconv [options]

       grpconv [options]

       grpunconv [options]

DESCRIPTION
       The pwconv command creates shadow from passwd and an optionally
       existing shadow.

       The pwunconv command creates a plain passwd from shadowed passwd and
       shadow and then removes shadow.

       The grpconv command creates gshadow from group and an optionally
       existing gshadow.

       The grpunconv command creates plain group from shadowed group and
       gshadow and then removes gshadow.

       These four programs all operate on the normal and shadow password and
       group files: /etc/passwd, /etc/group, /etc/shadow, and /etc/gshadow.

       Each program acquires the necessary locks before conversion.  pwconv
       and grpconv are similar. First, entries in the shadowed file which
       don't exist in the plain file are removed. Then, entries in the
       shadowed file which don't have `x' as the password in plain file are
       updated. Any missing shadowed entries are added. Finally, passwords in
       the plain file are replaced with `x'. These programs can be used for
       initial conversion as well to update the shadowed file if the plain
       file has been edited by hand.

       pwconv will use the values of PASS_MAX_DAYS, and PASS_WARN_AGE from
       /etc/login.defs when adding new entries to /etc/shadow.

       Likewise pwunconv and grpunconv are similar. Passwords in the plain
       file are updated from the shadowed file. Entries which exist in the
       plain file but not in the shadowed file are left alone. Finally, the
       shadowed file is removed. Some password aging information is lost by
       pwunconv. It will convert what it can.

OPTIONS
       The options which apply to the pwconv, pwunconv, grpconv, and grpunconv
       commands are:

       -h, --help
           Afficher un message d'aide et quitter.

       -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. No SELINUX support.

BOGUES
       Errors in the password or group files (such as invalid or duplicate
       entries) may cause these programs to loop forever or fail in other
       strange ways. Please run pwck and grpck to correct any such errors
       before converting to or from shadowed files.

CONFIGURATION
       The following configuration variable in /etc/login.defs changes the
       behavior of grpconv and grpunconv:

       MAX_MEMBERS_PER_GROUP (number)
           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).

           La valeur par defaut est 0, ce qui signifie qu'il n'y a pas de
           limites pour le nombre de membres dans un groupe.

           Cette fonctionnalite (groupe decoupe) permet de limiter la longueur
           des lignes dans le fichier de groupes. Ceci est utile pour
           s'assurer que les lignes pour les groupes NIS ne sont pas plus
           grandes que 1024 caracteres.

           Si vous avez besoin de configurer cette limite, vous pouvez
           utiliser 25.

           Remarque : les groupes decoupes ne sont peut-etre pas pris en
           charge par tous les outils (meme dans la suite d'outils Shadow).
           Vous ne devriez pas utiliser cette variable, sauf si vous en avez
           vraiment besoin.

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

       PASS_MAX_DAYS (number)
           Nombre maximum de jours de validite d'un mot de passe. Apres cette
           duree, une modification du mot de passe est obligatoire. S'il n'est
           pas precise, la valeur de -1 est utilisee (ce qui enleve toute
           restriction).

       PASS_WARN_AGE (number)
           The number of days warning given before a password expires. A zero
           means warning is given only upon the day of expiration, a value of
           -1 means no warning is given. If not specified, no warning will be
           provided.

FICHIERS
       /etc/login.defs
           Configuration de la suite des mots de passe caches << shadow
           password >>.

VOIR AUSSI
       grpck(8), login.defs(5), pwck(8).

shadow-utils 4.20.0               30/07/2026                         PWCONV(8)