Provided by:
passwd_4.1.4.2-1ubuntu2_i386 
NOME
pwconv, pwunconv, grpconv, grpunconv - convertono a e da password e
gruppi shadow.
SINOSSI
pwconv
pwunconv
grpconv
grpunconv
DESCRIZIONE
The pwconv command creates shadow from passwd and an optionally
existing shadow.
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.
Questi quattro programmi agiscono tutti sui file normali e oscurati
(shadow) delle password e dei gruppi: /etc/passwd, /etc/group,
/etc/shadow e /etc/gshadow.
Ciascun programma, prima della conversione, acquisisce i lock
necessari. pwconv e grpconv sono simili. Per prima cosa vengono
rimosse le voci nel file oscurato che non esistono nel file principale.
Quindi vengono aggiornate le voci oscurate che non hanno ‘x come
password nel file principale. Vengono aggiunte le eventuali voci
oscurate mancanti. Infine, le password nel file principale vengono
sostituite con ‘x. Questi programmi possono essere usati per le
conversioni iniziali così come per aggiornare il file oscurato se il
file principale viene editato a mano.
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.
Analogamente, pwunconv e grpunconv sono simili. Le password nel file
principale vengono aggiornate dal file oscurato. Voci che esistono nel
file principale ma non nel file oscurato vengono lasciate stare.
Infine, viene rimosso il file oscurato.Alcune informazioni
sullinvecchiamento delle password vengono perse da pwunconv. Convertirà
solo quello che potrà.
PROBLEMI
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.
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).
The default value is 0, meaning that there are no limits in the
number of members in a group.
This feature (split group) permits to limit the length of lines in
the group file. This is useful to make sure that lines for NIS
groups are not larger than 1024 characters.
If you need to enforce such limit, you can use 25.
Note: split groups may not be supported by all tools (even in the
Shadow toolsuite). You should not use this variable unless you
really need it.
The following configuration variables in /etc/login.defs change the
behavior of pwconv:
PASS_MAX_DAYS (number)
The maximum number of days a password may be used. If the password
is older than this, a password change will be forced. If not
specified, -1 will be assumed (which disables the restriction).
PASS_MIN_DAYS (number)
The minimum number of days allowed between password changes. Any
password changes attempted sooner than this will be rejected. If
not specified, -1 will be assumed (which disables the 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 negative
value means no warning is given. If not specified, no warning will
be provided.
FILE
/etc/login.defs
Shadow password suite configuration.
VEDERE ANCHE
grpck(8), login.defs(5), pwck(8).