The pwunconv command creates passwd from passwd and shadow and then removes shadow.
The grpconv command creates gshadow from group and an optionally existing gshadow.
The grpunconv command creates group from 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 main file are removed. Then, shadowed entries which don't have `x' as the password in the main file are updated. Any missing shadowed entries are added. Finally, passwords in the main file are replaced with `x'. These programs can be used for initial conversion as well to update the shadowed file if the main file is edited by hand.
pwconv will use the values of PASS_MIN_DAYS, 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 main file are updated from the shadowed file. Entries which exist in the main 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.
The options which apply to the pwconv, pwunconv, grpconv, and grpunconv commands are:
-h, --help
-R, --root CHROOT_DIR
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 shadow passwords or groups.
The following configuration variable in /etc/login.defs changes the behavior of grpconv and grpunconv:
MAX_MEMBERS_PER_GROUP (number)
Der Standardwert ist 0, was zur Folge hat, dass die Anzahl der Mitglieder einer Gruppe nicht begrenzt ist.
Diese Fähigkeit (der aufgeteilten Gruppe) ermöglicht es, die Zeilenlänge in der Gruppendatei zu begrenzen. Damit kann sichergestellt werden, dass die Zeilen für NIS-Gruppen nicht länger als 1024 Zeichen sind.
Falls Sie eine solche Begrenzung benötigen, können Sie 25 verwenden.
Hinweis: Aufgeteilte Gruppen werden möglicherweise nicht von allen Werkzeugen unterstützt, selbst nicht aus der Shadow-Werkzeugsammlung. Sie sollten diese Variable nur setzen, falls Sie zwingend darauf angewiesen sind.
The following configuration variables in /etc/login.defs change the behavior of pwconv:
PASS_MAX_DAYS (number)
PASS_MIN_DAYS (number)
PASS_WARN_AGE (number)
/etc/login.defs
grpck(8), login.defs(5), pwck(8).