Provided by: passwd_4.13+dfsg1-1ubuntu1.1_amd64 
NOM
useradd - créer un nouvel utilisateur ou modifier les informations par défaut appliquées
aux nouveaux utilisateurs
SYNOPSIS
useradd [options] LOGIN
useradd -D
useradd -D [options]
DESCRIPTION
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.
By default, a group will also be created for the new user (see -g, -N, -U, and
USERGROUPS_ENAB).
OPTIONS
The options which apply to the useradd command are:
--badname
Allow names that do not conform to standards.
-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 this option is not specified, useradd will use the base directory specified by the
HOME variable in /etc/default/useradd, or /home by default.
-c, --comment COMMENT
Any text string. It is generally a short description of the account, and is currently
used as the field for the user's full name.
-d, --home-dir 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. If the directory HOME_DIR does not exist, then it will be
created unless the -M option is specified.
-D, --defaults
Consultez ci-dessous la sous-section « Modifier les valeurs par défaut ».
-e, --expiredate EXPIRE_DATE
The date on which the user account will be disabled. The date is specified in the
format YYYY-MM-DD.
If not specified, useradd will use the default expiry date specified by the EXPIRE
variable in /etc/default/useradd, or an empty string (no expiry) by default.
-f, --inactive INACTIVE
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 shadow(5)for more
information.
If not specified, useradd will use the default inactivity period specified by the
INACTIVE variable in /etc/default/useradd, or -1 by default.
-F, --add-subids-for-system
Update /etc/subuid and /etc/subgid even when creating a system account with -r option.
-g, --gid GROUP
The name or the number of the user's primary group. The group name must exist. A group
number must refer to an already existing group.
If not specified, the behavior of useradd will depend on the USERGROUPS_ENAB variable
in /etc/login.defs. If this variable is set to yes (or -U/--user-group 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 no (or -N/--no-user-group is specified on the
command line), useradd will set the primary group of the new user to the value
specified by the GROUP variable in /etc/default/useradd, or 100 by default.
-G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
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 -g option. The default is
for the user to belong only to the initial group.
-h, --help
Afficher un message d'aide et quitter.
-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 specified.
If this option is not set, the skeleton directory is defined by the SKEL variable in
/etc/default/useradd or, by default, /etc/skel.
Si possible, les ACL et les attributs étendus seront copiés.
-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 an account to turn off
password aging. Multiple -K options can be specified, e.g.: -K UID_MIN =100 -K
UID_MAX=499
For the compatibility with previous Debian's useradd, the -O option is also supported.
-l, --no-log-init
N'ajoute pas l'utilisateur aux bases de données lastlog et faillog.
Par défaut, les entrées de l'utilisateur dans les bases de données lastlog et faillog
sont remises à zéro pour éviter de réutiliser les entrées d'un utilisateur
précédemment supprimé.
If this option is not specified, useradd will also consult the variable LOG_INIT in
the /etc/default/useradd if set to no the user will not be added to the lastlog and
faillog databases.
-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, if this option is not specified and CREATE_HOME is not enabled, no home
directories are created.
The directory where the user's home directory is created must exist and have proper
SELinux context and permissions. Otherwise the user's home directory cannot be created
or accessed.
-M, --no-create-home
Do not create the user's home directory, even if the system wide setting from
/etc/login.defs (CREATE_HOME) is set to yes.
-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 /etc/login.defs.
-o, --non-unique
allows the creation of an account with an already existing UID.
This option is only valid in combination with the -u 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's behavior on the other hand, more than one login
name will access the account of the given UID.
-p, --password PASSWORD
defines an initial password for the account. PASSWORD is expected to be encrypted, as
returned by crypt (3). Within a shell script, this option allows to create efficiently
batches of users.
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't be able to access the account or to define a password himself.
Note:Avoid this option on the command line because the password (or encrypted
password) will be visible by users listing the processes.
Il est nécessaire de vérifier si le mot de passe respecte la politique de mots de
passe du système.
-r, --system
Créer un compte système.
System users will be created with no aging information in /etc/shadow, and their
numeric identifiers are chosen in the SYS_UID_MIN-SYS_UID_MAX range, defined in
/etc/login.defs, instead of UID_MIN-UID_MAX (and their GID counterparts for the
creation of groups).
Note that useradd will not create a home directory for such a user, regardless of the
default setting in /etc/login.defs (CREATE_HOME). You have to specify the -m options
if you want a home directory for a system account to be created.
Note that this option will not update /etc/subuid and /etc/subgid. You have to specify
the -F options if you want to update the files for a system account to be created.
-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.
-P, --prefix PREFIX_DIR
Apply changes to configuration files under the root filesystem found under the
directory PREFIX_DIR. 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.
-s, --shell SHELL
sets the path to the user's login shell. Without this option, the system will use the
SHELL 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.
-u, --uid UID
The numerical value of the user's ID. This value must be unique, unless the -o option
is used. The value must be non-negative. The default is to use the smallest ID value
greater than or equal to UID_MIN and greater than every other user.
See also the -r option and the UID_MAX description.
-U, --user-group
Crée un groupe avec le même nom que celui de l'utilisateur, et ajoute l'utilisateur à
ce groupe.
The default behavior (if the -g, -N, and -U options are not specified) is defined by
the USERGROUPS_ENAB variable in /etc/login.defs.
-Z, --selinux-user SEUSER
defines the SELinux user for the new account. Without this option, a SELinux uses the
default user. Note that the shadow system doesn't store the selinux-user, it uses
semanage(8) for that.
Modifier les valeurs par défaut
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
sets 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 account.
This option sets the HOME variable in /etc/default/useradd.
-e, --expiredate EXPIRE_DATE
sets the date on which newly created user accounts are disabled.
This option sets the EXPIRE variable in /etc/default/useradd.
-f, --inactive INACTIVE
defines the number of days after the password exceeded its maximum age where the user
is expected to replace this password. See shadow(5)for more information.
This option sets the INACTIVE variable in /etc/default/useradd.
-g, --gid GROUP
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.
This option sets the GROUP variable in /etc/default/useradd.
-s, --shell SHELL
defines the default login shell for new users.
This option sets the SHELL variable in /etc/default/useradd.
NOTES
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).
AVERTISSEMENTS
Vous ne pouvez pas ajouter d'utilisateur à un groupe NIS ou LDAP. Cela doit être effectué
sur le serveur correspondant.
Similarly, if the username already exists in an external user database such as NIS or
LDAP, useradd will deny the user account creation request.
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 ls output.
On Debian, the only constraints are that usernames must neither start with a dash ('-')
nor plus ('+') nor tilde ('~') nor contain a colon (':'), a comma (','), or a whitespace
(space: ' ', end of line: '\n', tabulation: '\t', etc.). Note that using a slash ('/') may
break the default algorithm for the definition of the user's home directory.
On Ubuntu, the same constraints as Debian are in place, with the additional constraint
that the username cannot be fully numeric. This includes octal and hexadecimal syntax.
Les noms d'utilisateur sont limités à 16 caractères.
CONFIGURATION
The following configuration variables in /etc/login.defs change the behavior of this tool:
FICHIERS
/etc/passwd
Informations sur les comptes des utilisateurs.
/etc/shadow
Informations sécurisées sur les comptes utilisateurs.
/etc/group
Informations sur les groupes.
/etc/gshadow
Informations sécurisées sur les groupes.
/etc/default/useradd
Valeurs par défaut pour la création de comptes.
/etc/shadow-maint/useradd-pre.d/*, /etc/shadow-maint/useradd-post.d/*
Run-part files to execute during user addition. The environment variable ACTION will
be populated with useradd and SUBJECT with the username. 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.
/etc/skel/
Répertoire contenant les fichiers par défaut.
/etc/subgid
IDs des groupes subalternes d'un utilisateur.
/etc/subuid
IDs de utilisateurs subalternes d'un utilisateur.
/etc/login.defs
Configuration de la suite des mots de passe cachés « shadow password ».
VALEURS DE RETOUR
The useradd command exits with the following values:
0
success
1
can't update password file
2
invalid command syntax
3
invalid argument to option
4
UID already in use (and no -o)
6
specified group doesn't exist
9
username or group name already in use
10
can't update group file
12
can't create home directory
14
can't update SELinux user mapping
VOIR AUSSI
chfn(1), chsh(1), passwd(1), crypt(3), groupadd(8), groupdel(8), groupmod(8),
login.defs(5), newusers(8), subgid(5), subuid(5), userdel(8), usermod(8).