Provided by: passwd_4.1.1-6ubuntu6_i386 bug


       useradd - crea un nuovo utente o aggiorna le informazioni predefinite
       per i nuovi utenti


       useradd [opzioni] LOGIN

       useradd -D

       useradd -D [opzioni]


       useradd is a low level utility for adding users. On Debian,
       administrators should usually use adduser(8) instead.

       When invoked without the -D option, the useradd command creates a new
       user account using the values specified on the command line plus the
       default values from the system. Depending on command line options, the
       useradd command will update system files and may also create the new
       user´s home directory and copy initial files.


       Il comando useradd accetta le seguenti opzioni:

       -c, --comment COMMENT
           Any text string. It is generally a short description of the login,
           and is currently used as the field for the user´s full name.

       -b, --base-dir BASE_DIR
           The default base directory for the system if -d HOME_DIR is not
           specified.  BASE_DIR is concatenated with the account name to
           define the home directory. If the -m option is not used, BASE_DIR
           must exist.

       -D, --defaults
           See below, the subsection "Changing the default values".

       -d, --home HOME_DIR
           The new user will be created using HOME_DIR as the value for the
           user´s login directory. The default is to append the LOGIN name to
           BASE_DIR and use that as the login directory name. The directory
           HOME_DIR does not have to exist but will not be created if it is

       -e, --expiredate EXPIRE_DATE
           La data in cui l´account dell´utente verrà disabilitato. La data è
           specificata nel formato MM/GG/AA.

       -f, --inactive INACTIVE
           Il numero di giorni dopo la scadenza della password prima che
           l´account verrà permanentemente disabilitato. Un valore pari a 0
           disabilita l´account non appena la password è scaduta, ed un valore
           pari a -1 disabilita questa caratteristica. Il valore predefinito è

       -g, --gid GROUP
           The group name or number of the user´s initial login group. The
           group name must exist. A group number must refer to an already
           existing group. The default group number is 1 or whatever is
           specified in /etc/default/useradd.

       -G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
           Una lista di gruppi supplementari di cui l´utente è altresì membro.
           Ciascun gruppo è separato dal successivo da una virgola, senza
           spazi bianchi intermedi. I gruppi sono soggetti alle stesse
           restrizioni del gruppo dato con l´opzione -g. Il comportamento
           predefinito è che l´utente appartenga solo al gruppo iniziale.

       -h, --help
           Mostra un messaggio di aiuto ed esce.

       -k, --skel SKEL_DIR
           The skeleton directory, which contains files and directories to be
           copied in the user´s home directory, when the home directory is
           created by useradd.

           This option is only valid if the -m (or --create-home) option is

           If this option is not set, the skeleton directory is defined in
           /etc/default/useradd or, by default, /etc/skel.

           This option may not function correctly if the username has a / in

       -K, --key KEY=VALUE
           Overrides /etc/login.defs defaults (UID_MIN, UID_MAX, UMASK,
           PASS_MAX_DAYS and others).

           Example: -K PASS_MAX_DAYS=-1 can be used when creating system
           account to turn off password ageing, even though system account has
           no password at all. Multiple -K options can be specified, e.g.: -K
            -K UID_MAX=499

           Note: -K UID_MIN=10,UID_MAX=499 doesn´t work yet.

           For the compatibility with previous Debian´s useradd, the -O option
           is also supported.

           Do not add the user to the lastlog and faillog databases.

           By default, the user´s entries in the lastlog and faillog databases
           are resetted to avoid reusing the entry from a previously deleted

       -m, --create-home
           Create the user´s home directory if it does not exist. The files
           and directories contained in the skeleton directory (which can be
           defined with the -k option) will be copied to the home directory.

           By default, no home directories are created.

       -N, --no-user-group
           Do not create a group with the same name as the user, but add the
           user to the group specified by the -g option or by the GROUP
           variable in /etc/default/useradd.

           The default behavior (if the -g, -N, and -U options are not
           specified) is defined by the USERGROUPS_ENAB variable in

       -o, --non-unique
           Allow the creation of a user account with a duplicate (non-unique)

       -p, --password PASSWORD
           The encrypted password, as returned by crypt(3). The default is to
           disable the account.

       -r, --system
           Create a system account.

           System users will be created with no aging information in
           /etc/shadow, and their numeric identifiers are choosen in the
           SYS_UID_MIN-SYS_UID_MAX range, defined in login.defs, instead of
           UID_MIN-UID_MAX (and their GID counterparts for the creation of

       -s, --shell SHELL
           Il nome della shell di login dell´utente. Il comportamento
           predefinito è di lasciare vuoto questo campo, che fa sì che il
           sistema selezioni la shell di connessione predefinita.

       -u, --uid UID
           Il valore numerico dell´identificatore (ID) del gruppo. Questo
           valore deve essere univoco, a meno che non venga usata l´opzione
           -o. Il valore deve essere non-negativo. La scelta predefinita è
           quella di usare il minimo valore di ID superiore a 999 e superiore
           a qualunque altro gruppo. Valori tra 0 e 999 sono tipicamente
           riservati per account di sistema.

       -U, --user-group
           Create a group with the same name as the user, and add the user to
           this group.

           The default behavior (if the -g, -N, and -U options are not
           specified) is defined by the USERGROUPS_ENAB variable in

   Cambiare i valori predefiniti
       When invoked with only the -D option, useradd will display the current
       default values. When invoked with -D plus other options, useradd will
       update the default values for the specified options. Valid
       default-changing options are:

       -b, --base-dir BASE_DIR
           The path prefix for a new user´s home directory. The user´s name
           will be affixed to the end of BASE_DIR to form the new user´s home
           directory name, if the -d option is not used when creating a new

       -e, --expiredate EXPIRE_DATE
           La data in cui l´account dell´utente verrà disabilitato.

       -f, --inactive INACTIVE
           Il numero di giorni dopo la scadenza di una password prima che
           l´account venga disabilitato.

       -g, --gid GROUP
           Il nome o ID del gruppo iniziale per un nuovo utente. Il gruppo
           nominato deve esistere, ed un ID numerico di gruppo deve avere una
           voce esistente.

       -s, --shell SHELL
           The name of a new user´s login shell.


       L´amministratore di sistema è responsabile del posizionamento dei file
       predefiniti degli utenti nella directory /etc/skel/.


       You may not add a user to a NIS or LDAP group. This must be performed
       on the corresponding server.

       Similarly, if the username already exists in an external user database
       such as NIS or LDAP, useradd will deny the user account creation

       It is usually recommended to only use usernames that begin with a lower
       case letter or an underscore, and are only followed by lower case
       letters, digits, underscores, dashes, and optionally terminated by a
       dollar sign. In regular expression terms: [a-z_][a-z0-9_-]*[$]?

       On Debian, the only constraints are that usernames must neither start
       with a dash (´-´) nor contain a colon (´:´) or a whitespace (space:´ ´,
       end of line: ´\n´, tabulation: ´\t´, etc.).

       Usernames may only be up to 32 characters long.


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

       GID_MAX (number), GID_MIN (number)
           Range of group IDs used for the creation of regular groups by
           useradd, useradd, or newusers.

       MAIL_DIR (string)
           The mail spool directory. This is needed to manipulate the mailbox
           when its corresponding user account is modified or deleted. If not
           specified, a compile-time default is used.

       MAIL_FILE (string)
           Defines the location of the users mail spool files relatively to
           their home directory.

       The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
       userdel to create, move, or delete the user´s mail spool.

       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.

       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.

       SYS_GID_MAX (number), SYS_GID_MIN (number)
           Range of group IDs used for the creation of system groups by
           useradd, groupadd, or newusers.

       SYS_UID_MAX (number), SYS_UID_MIN (number)
           Range of user IDs used for the creation of system users by useradd
           or newusers.

       UID_MAX (number), UID_MIN (number)
           Range of user IDs used for the creation of regular users by useradd
           or newusers.

       UMASK (number)
           The permission mask is initialized to this value. If not specified,
           the permission mask will be initialized to 022.

       USERGROUPS_ENAB (boolean)


           informazioni sugli account utente.

           Informazioni sicure sugli account di utenti.

           Informazioni sugli account di gruppo.

           Default values for account creation.

           Directory contenente i file predefiniti.

           Shadow password suite configuration.


       The useradd command exits with the following values:


           can´t update password file

           sintassi del comando errata

           invalid argument to option

           UID already in use (and no -o)

           il gruppo specificato non esiste

           username already in use

           non è possibile aggiornare il file group

           can´t create home directory

           can´t create mail spool


       chfn(1), chsh(1), passwd(1), crypt(3), groupadd(8), groupdel(8),
       groupmod(8), login.defs(5), newusers(8), userdel(8), usermod(8).