'\" t
.\"     Title: useradd
.\"    Author: Julianne Frances Haugh
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 04/02/2024
.\"    Manual: Comandi per la gestione del sistema
.\"    Source: shadow-utils 4.13
.\"  Language: Italian
.\"
.TH "USERADD" "8" "04/02/2024" "shadow\-utils 4\&.13" "Comandi per la gestione del si"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NOME"
useradd \- crea un nuovo utente o aggiorna le informazioni predefinite per i nuovi utenti
.SH "SINOSSI"
.HP \w'\fBuseradd\fR\ 'u
\fBuseradd\fR [\fIopzioni\fR] \fILOGIN\fR
.HP \w'\fBuseradd\fR\ 'u
\fBuseradd\fR \-D
.HP \w'\fBuseradd\fR\ 'u
\fBuseradd\fR \-D [\fIopzioni\fR]
.SH "DESCRIZIONE"
.PP
\fBuseradd\fR
is a low level utility for adding users\&. On Debian, administrators should usually use
\fBadduser\fR(8)
instead\&.
.PP
When invoked without the
\fB\-D\fR
option, the
\fBuseradd\fR
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
\fBuseradd\fR
command will update system files and may also create the new user\*(Aqs home directory and copy initial files\&.
.PP
By default, a group will also be created for the new user (see
\fB\-g\fR,
\fB\-N\fR,
\fB\-U\fR, and
\fBUSERGROUPS_ENAB\fR)\&.
.SH "OPZIONI"
.PP
The options which apply to the
\fBuseradd\fR
command are:
.PP
\fB\-\-badname\fR\ \&
.RS 4
Allow names that do not conform to standards\&.
.RE
.PP
\fB\-b\fR, \fB\-\-base\-dir\fR\ \&\fIBASE_DIR\fR
.RS 4
The default base directory for the system if
\fB\-d\fR\ \&\fIHOME_DIR\fR
is not specified\&.
\fIBASE_DIR\fR
is concatenated with the account name to define the home directory\&.
.sp
If this option is not specified,
\fBuseradd\fR
will use the base directory specified by the
\fBHOME\fR
variable in
/etc/default/useradd, or
/home
by default\&.
.RE
.PP
\fB\-c\fR, \fB\-\-comment\fR\ \&\fICOMMENT\fR
.RS 4
Any text string\&. It is generally a short description of the account, and is currently used as the field for the user\*(Aqs full name\&.
.RE
.PP
\fB\-d\fR, \fB\-\-home\-dir\fR\ \&\fIHOME_DIR\fR
.RS 4
The new user will be created using
\fIHOME_DIR\fR
as the value for the user\*(Aqs login directory\&. The default is to append the
\fILOGIN\fR
name to
\fIBASE_DIR\fR
and use that as the login directory name\&. If the directory
\fIHOME_DIR\fR
does not exist, then it will be created unless the
\fB\-M\fR
option is specified\&.
.RE
.PP
\fB\-D\fR, \fB\-\-defaults\fR
.RS 4
Vedere oltre, la sezione \(FoCambiare i valori predefiniti\(Fc\&.
.RE
.PP
\fB\-e\fR, \fB\-\-expiredate\fR\ \&\fIEXPIRE_DATE\fR
.RS 4
The date on which the user account will be disabled\&. The date is specified in the format
\fIYYYY\-MM\-DD\fR\&.
.sp
If not specified,
\fBuseradd\fR
will use the default expiry date specified by the
\fBEXPIRE\fR
variable in
/etc/default/useradd, or an empty string (no expiry) by default\&.
.RE
.PP
\fB\-f\fR, \fB\-\-inactive\fR\ \&\fIINACTIVE\fR
.RS 4
defines the number of days after the password exceeded its maximum age where the user is expected to replace this password\&. The value is stored in the shadow password file\&. An input of 0 will disable an expired password with no delay\&. An input of \-1 will blank the respective field in the shadow password file\&. See
\fBshadow\fR(5)for more information\&.
.sp
If not specified,
\fBuseradd\fR
will use the default inactivity period specified by the
\fBINACTIVE\fR
variable in
/etc/default/useradd, or \-1 by default\&.
.RE
.PP
\fB\-F\fR, \fB\-\-add\-subids\-for\-system\fR
.RS 4
Update
/etc/subuid
and
/etc/subgid
even when creating a system account with
\fB\-r\fR
option\&.
.RE
.PP
\fB\-g\fR, \fB\-\-gid\fR\ \&\fIGROUP\fR
.RS 4
The name or the number of the user\*(Aqs primary group\&. The group name must exist\&. A group number must refer to an already existing group\&.
.sp
If not specified, the behavior of
\fBuseradd\fR
will depend on the
\fBUSERGROUPS_ENAB\fR
variable in
/etc/login\&.defs\&. If this variable is set to
\fIyes\fR
(or
\fB\-U/\-\-user\-group\fR
is specified on the command line), a group will be created for the user, with the same name as her loginname\&. If the variable is set to
\fIno\fR
(or
\fB\-N/\-\-no\-user\-group\fR
is specified on the command line), useradd will set the primary group of the new user to the value specified by the
\fBGROUP\fR
variable in
/etc/default/useradd, or 100 by default\&.
.RE
.PP
\fB\-G\fR, \fB\-\-groups\fR\ \&\fIGROUP1\fR[\fI,GROUP2,\&.\&.\&.\fR[\fI,GROUPN\fR]]]
.RS 4
A list of supplementary groups which the user is also a member of\&. Each group is separated from the next by a comma, with no intervening whitespace\&. The groups are subject to the same restrictions as the group given with the
\fB\-g\fR
option\&. The default is for the user to belong only to the initial group\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Mostra un messaggio di aiuto ed esce\&.
.RE
.PP
\fB\-k\fR, \fB\-\-skel\fR\ \&\fISKEL_DIR\fR
.RS 4
The skeleton directory, which contains files and directories to be copied in the user\*(Aqs home directory, when the home directory is created by
\fBuseradd\fR\&.
.sp
This option is only valid if the
\fB\-m\fR
(or
\fB\-\-create\-home\fR) option is specified\&.
.sp
If this option is not set, the skeleton directory is defined by the
\fBSKEL\fR
variable in
/etc/default/useradd
or, by default,
/etc/skel\&.
.sp
Se possibile vengono copiate le ACL e gli attributi estesi\&.
.RE
.PP
\fB\-K\fR, \fB\-\-key\fR\ \&\fIKEY\fR=\fIVALUE\fR
.RS 4
Overrides
/etc/login\&.defs
defaults (\fBUID_MIN\fR,
\fBUID_MAX\fR,
\fBUMASK\fR,
\fBPASS_MAX_DAYS\fR
and others)\&.
.sp
Example:
\fB\-K\fR\ \&\fIPASS_MAX_DAYS \fR=\fI\-1\fR
can be used when creating an account to turn off password aging\&. Multiple
\fB\-K\fR
options can be specified, e\&.g\&.:
\fB\-K\fR\ \&\fIUID_MIN\fR
=\fI100\fR\ \&\fB\-K\fR\ \&
\fIUID_MAX\fR=\fI499\fR
.sp
For the compatibility with previous Debian\*(Aqs
\fBuseradd\fR, the
\fB\-O\fR
option is also supported\&.
.RE
.PP
\fB\-l\fR, \fB\-\-no\-log\-init\fR
.RS 4
Non aggiunge l\*(Aqutente ai database \(Folastlog\(Fc e \(Fofaillog\(Fc\&.
.sp
By default, the user\*(Aqs entries in the lastlog and faillog databases are reset to avoid reusing the entry from a previously deleted user\&.
.sp
If this option is not specified,
\fBuseradd\fR
will also consult the variable
\fBLOG_INIT\fR
in the
/etc/default/useradd
if set to no the user will not be added to the lastlog and faillog databases\&.
.RE
.PP
\fB\-m\fR, \fB\-\-create\-home\fR
.RS 4
Create the user\*(Aqs home directory if it does not exist\&. The files and directories contained in the skeleton directory (which can be defined with the
\fB\-k\fR
option) will be copied to the home directory\&.
.sp
By default, if this option is not specified and
\fBCREATE_HOME\fR
is not enabled, no home directories are created\&.
.sp
The directory where the user\*(Aqs home directory is created must exist and have proper SELinux context and permissions\&. Otherwise the user\*(Aqs home directory cannot be created or accessed\&.
.RE
.PP
\fB\-M\fR, \fB\-\-no\-create\-home\fR
.RS 4
Do not create the user\*(Aqs home directory, even if the system wide setting from
/etc/login\&.defs
(\fBCREATE_HOME\fR) is set to
\fIyes\fR\&.
.RE
.PP
\fB\-N\fR, \fB\-\-no\-user\-group\fR
.RS 4
Do not create a group with the same name as the user, but add the user to the group specified by the
\fB\-g\fR
option or by the
\fBGROUP\fR
variable in
/etc/default/useradd\&.
.sp
The default behavior (if the
\fB\-g\fR,
\fB\-N\fR, and
\fB\-U\fR
options are not specified) is defined by the
\fBUSERGROUPS_ENAB\fR
variable in
/etc/login\&.defs\&.
.RE
.PP
\fB\-o\fR, \fB\-\-non\-unique\fR
.RS 4
allows the creation of an account with an already existing UID\&.
.sp
This option is only valid in combination with the
\fB\-u\fR
option\&. As a user identity serves as key to map between users on one hand and permissions, file ownerships and other aspects that determine the system\*(Aqs behavior on the other hand, more than one login name will access the account of the given UID\&.
.RE
.PP
\fB\-p\fR, \fB\-\-password\fR\ \&\fIPASSWORD\fR
.RS 4
defines an initial password for the account\&. PASSWORD is expected to be encrypted, as returned by
\fBcrypt \fR(3)\&. Within a shell script, this option allows to create efficiently batches of users\&.
.sp
Without this option, the new account will be locked and with no password defined, i\&.e\&. a single exclamation mark in the respective field of
/etc/shadow\&. This is a state where the user won\*(Aqt be able to access the account or to define a password himself\&.
.sp
\fBNote:\fRAvoid this option on the command line because the password (or encrypted password) will be visible by users listing the processes\&.
.sp
Ci si deve accertare che la password rispetti le norme delle password del sistema\&.
.RE
.PP
\fB\-r\fR, \fB\-\-system\fR
.RS 4
Crea un account di sistema\&.
.sp
System users will be created with no aging information in
/etc/shadow, and their numeric identifiers are chosen in the
\fBSYS_UID_MIN\fR\-\fBSYS_UID_MAX\fR
range, defined in
/etc/login\&.defs, instead of
\fBUID_MIN\fR\-\fBUID_MAX\fR
(and their
\fBGID\fR
counterparts for the creation of groups)\&.
.sp
Note that
\fBuseradd\fR
will not create a home directory for such a user, regardless of the default setting in
/etc/login\&.defs
(\fBCREATE_HOME\fR)\&. You have to specify the
\fB\-m\fR
options if you want a home directory for a system account to be created\&.
.sp
Note that this option will not update
/etc/subuid
and
/etc/subgid\&. You have to specify the
\fB\-F\fR
options if you want to update the files for a system account to be created\&.
.RE
.PP
\fB\-R\fR, \fB\-\-root\fR\ \&\fICHROOT_DIR\fR
.RS 4
Apply changes in the
\fICHROOT_DIR\fR
directory and use the configuration files from the
\fICHROOT_DIR\fR
directory\&. Only absolute paths are supported\&.
.RE
.PP
\fB\-P\fR, \fB\-\-prefix\fR\ \&\fIPREFIX_DIR\fR
.RS 4
Apply changes to configuration files under the root filesystem found under the directory
\fIPREFIX_DIR\fR\&. 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\&.
.RE
.PP
\fB\-s\fR, \fB\-\-shell\fR\ \&\fISHELL\fR
.RS 4
sets the path to the user\*(Aqs login shell\&. Without this option, the system will use the
\fBSHELL\fR
variable specified in
/etc/default/useradd, or, if that is as well not set, the field for the login shell in
/etc/passwd
remains empty\&.
.RE
.PP
\fB\-u\fR, \fB\-\-uid\fR\ \&\fIUID\fR
.RS 4
The numerical value of the user\*(Aqs ID\&. This value must be unique, unless the
\fB\-o\fR
option is used\&. The value must be non\-negative\&. The default is to use the smallest ID value greater than or equal to
\fBUID_MIN\fR
and greater than every other user\&.
.sp
See also the
\fB\-r\fR
option and the
\fBUID_MAX\fR
description\&.
.RE
.PP
\fB\-U\fR, \fB\-\-user\-group\fR
.RS 4
Crea un gruppo con lo stesso nome dell\*(Aqutente e aggiunge l\*(Aqutente al gruppo stesso\&.
.sp
The default behavior (if the
\fB\-g\fR,
\fB\-N\fR, and
\fB\-U\fR
options are not specified) is defined by the
\fBUSERGROUPS_ENAB\fR
variable in
/etc/login\&.defs\&.
.RE
.PP
\fB\-Z\fR, \fB\-\-selinux\-user\fR\ \&\fISEUSER\fR
.RS 4
defines the SELinux user for the new account\&. Without this option, a SELinux uses the default user\&. Note that the shadow system doesn\*(Aqt store the selinux\-user, it uses
\fBsemanage\fR(8)
for that\&.
.RE
.SS "Cambiare i valori predefiniti"
.PP
When invoked with only the
\fB\-D\fR
option,
\fBuseradd\fR
will display the current default values\&. When invoked with
\fB\-D\fR
plus other options,
\fBuseradd\fR
will update the default values for the specified options\&. Valid default\-changing options are:
.PP
\fB\-b\fR, \fB\-\-base\-dir\fR\ \&\fIBASE_DIR\fR
.RS 4
sets the path prefix for a new user\*(Aqs home directory\&. The user\*(Aqs name will be affixed to the end of
\fIBASE_DIR\fR
to form the new user\*(Aqs home directory name, if the
\fB\-d\fR
option is not used when creating a new account\&.
.sp
This option sets the
\fBHOME\fR
variable in
/etc/default/useradd\&.
.RE
.PP
\fB\-e\fR, \fB\-\-expiredate\fR\ \&\fIEXPIRE_DATE\fR
.RS 4
sets the date on which newly created user accounts are disabled\&.
.sp
This option sets the
\fBEXPIRE\fR
variable in
/etc/default/useradd\&.
.RE
.PP
\fB\-f\fR, \fB\-\-inactive\fR\ \&\fIINACTIVE\fR
.RS 4
defines the number of days after the password exceeded its maximum age where the user is expected to replace this password\&. See
\fBshadow\fR(5)for more information\&.
.sp
This option sets the
\fBINACTIVE\fR
variable in
/etc/default/useradd\&.
.RE
.PP
\fB\-g\fR, \fB\-\-gid\fR\ \&\fIGROUP\fR
.RS 4
sets the default primary group for newly created users, accepting group names or a numerical group ID\&. The named group must exist, and the GID must have an existing entry\&.
.sp
This option sets the
\fBGROUP\fR
variable in
/etc/default/useradd\&.
.RE
.PP
\fB\-s\fR, \fB\-\-shell\fR\ \&\fISHELL\fR
.RS 4
defines the default login shell for new users\&.
.sp
This option sets the
\fBSHELL\fR
variable in
/etc/default/useradd\&.
.RE
.SH "NOTE"
.PP
The system administrator is responsible for placing the default user files in the
/etc/skel/
directory (or any other skeleton directory specified in
/etc/default/useradd
or on the command line)\&.
.SH "AVVISI/CAVEAT"
.PP
Non \(`e possibile aggiungere un utente ad un gruppo NIS o LDAP\&. Questo deve essere fatto sul server corrispondente\&.
.PP
Similarly, if the username already exists in an external user database such as NIS or LDAP,
\fBuseradd\fR
will deny the user account creation request\&.
.PP
Usernames may contain only lower and upper case letters, digits, underscores, or dashes\&. They can end with a dollar sign\&. Dashes are not allowed at the beginning of the username\&. Fully numeric usernames and usernames \&. or \&.\&. are also disallowed\&. It is not recommended to use usernames beginning with \&. character as their home directories will be hidden in the
\fBls\fR
output\&.
.PP
On Debian, the only constraints are that usernames must neither start with a dash (\*(Aq\-\*(Aq) nor plus (\*(Aq+\*(Aq) nor tilde (\*(Aq~\*(Aq) nor contain a colon (\*(Aq:\*(Aq), a comma (\*(Aq,\*(Aq), or a whitespace (space: \*(Aq \*(Aq, end of line: \*(Aq\en\*(Aq, tabulation: \*(Aq\et\*(Aq, etc\&.)\&. Note that using a slash (\*(Aq/\*(Aq) may break the default algorithm for the definition of the user\*(Aqs home directory\&.
.PP
I nomi utente non possono eccedere i 32 caratteri di lunghezza\&.
.SH "CONFIGURAZIONE"
.PP
The following configuration variables in
/etc/login\&.defs
change the behavior of this tool:
.SH "FILE"
.PP
/etc/passwd
.RS 4
Informazioni sugli account utente\&.
.RE
.PP
/etc/shadow
.RS 4
Informazioni sicure sugli account utente\&.
.RE
.PP
/etc/group
.RS 4
Informazioni sugli account di gruppo\&.
.RE
.PP
/etc/gshadow
.RS 4
Informazioni sicure sugli account di gruppo\&.
.RE
.PP
/etc/default/useradd
.RS 4
Valori predefiniti per la creazione dell\*(Aqaccount\&.
.RE
.PP
/etc/shadow\-maint/useradd\-pre\&.d/*, /etc/shadow\-maint/useradd\-post\&.d/*
.RS 4
Run\-part files to execute during user addition\&. The environment variable
\fBACTION\fR
will be populated with useradd and
\fBSUBJECT\fR
with the
\fBusername\fR\&.
useradd\-pre\&.d
will be executed prior to any user addition\&.
useradd\-post\&.d
will execute after user addition\&. If a script exits non\-zero then execution will terminate\&.
.RE
.PP
/etc/skel/
.RS 4
Directory contenente i file predefiniti\&.
.RE
.PP
/etc/subgid
.RS 4
Per user subordinate group IDs\&.
.RE
.PP
/etc/subuid
.RS 4
Per user subordinate user IDs\&.
.RE
.PP
/etc/login\&.defs
.RS 4
Configurazione del pacchetto password shadow
.RE
.SH "VALORI RESTITUITI"
.PP
The
\fBuseradd\fR
command exits with the following values:
.PP
\fI0\fR
.RS 4
success
.RE
.PP
\fI1\fR
.RS 4
can\*(Aqt update password file
.RE
.PP
\fI2\fR
.RS 4
invalid command syntax
.RE
.PP
\fI3\fR
.RS 4
invalid argument to option
.RE
.PP
\fI4\fR
.RS 4
UID already in use (and no
\fB\-o\fR)
.RE
.PP
\fI6\fR
.RS 4
specified group doesn\*(Aqt exist
.RE
.PP
\fI9\fR
.RS 4
username or group name already in use
.RE
.PP
\fI10\fR
.RS 4
can\*(Aqt update group file
.RE
.PP
\fI12\fR
.RS 4
can\*(Aqt create home directory
.RE
.PP
\fI14\fR
.RS 4
can\*(Aqt update SELinux user mapping
.RE
.SH "VEDERE ANCHE"
.PP
\fBchfn\fR(1),
\fBchsh\fR(1),
\fBpasswd\fR(1),
\fBcrypt\fR(3),
\fBgroupadd\fR(8),
\fBgroupdel\fR(8),
\fBgroupmod\fR(8),
\fBlogin.defs\fR(5),
\fBnewusers\fR(8),
\fBsubgid\fR(5), \fBsubuid\fR(5),
\fBuserdel\fR(8),
\fBusermod\fR(8)\&.