USERADD(8)						    System Management Commands							USERADD(8)

NAME

       useradd - create a new user or update default new user information

SYNOPSIS

       useradd [options] LOGIN

       useradd -D

       useradd -D [options]

DESCRIPTION

       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:

       -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.

	   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 login, 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. The directory HOME_DIR does not have to exist but will not be created if it is
	   missing.

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

       -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
	   The number of days after a password expires until the account is permanently disabled. A value of 0 disables the account as soon as the
	   password has expired, and a value of -1 disables the feature.

	   If not specified, useradd will use the default inactivity period specified by the INACTIVE variable in /etc/default/useradd, or -1 by
	   default.

       -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.

	   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
	   Display help message and exit.

       -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.

	   If possible, the ACLs and extended attributes are copied.

       -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 UID_MIN=100 -K UID_MAX=499

       -l, --no-log-init
	   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
	   user.

       -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
	   Allow the creation of a user account with a duplicate (non-unique) UID.

	   This option is only valid in combination with the -u option.

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

	   Note: This option is not recommended because the password (or encrypted password) will be visible by users listing the processes.

	   You should make sure the password respects the system's password policy.

       -r, --system
	   Create a system account.

	   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 an 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.

       -R, --root CHROOT_DIR
	   Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory.

       -s, --shell SHELL
	   The name of the user's login shell. The default is to leave this field blank, which causes the system to select the default login shell
	   specified by the SHELL variable in /etc/default/useradd, or an empty string by default.

       -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
	   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 /etc/login.defs.

       -Z, --selinux-user SEUSER
	   The SELinux user for the user's login. The default is to leave this field blank, which causes the system to select the default SELinux
	   user.

   Changing the default values
       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 account.

	   This option sets the HOME variable in /etc/default/useradd.

       -e, --expiredate EXPIRE_DATE
	   The date on which the user account is disabled.

	   This option sets the EXPIRE variable in /etc/default/useradd.

       -f, --inactive INACTIVE
	   The number of days after a password has expired before the account will be disabled.

	   This option sets the INACTIVE variable in /etc/default/useradd.

       -g, --gid GROUP
	   The group name or ID for a new user's initial group (when the -N/--no-user-group is used or when the USERGROUPS_ENAB variable is set to
	   no in /etc/login.defs). The named group must exist, and a numerical group ID must have an existing entry.

	   This option sets the GROUP variable in /etc/default/useradd.

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

	   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).

CAVEATS

       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
       request.

       Usernames may only be up to 32 characters long.

CONFIGURATION

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

       CREATE_HOME (boolean)
	   Indicate if a home directory should be created by default for new users.

	   This setting does not apply to system users, and can be overridden on the command line.

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

	   The default value for GID_MIN (resp.  GID_MAX) is 1000 (resp. 60000).

       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.

       If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL environment variable.

       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.

	   The default value for SYS_GID_MIN (resp.  SYS_GID_MAX) is 101 (resp.  GID_MIN-1).

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

	   The default value for SYS_UID_MIN (resp.  SYS_UID_MAX) is 101 (resp.  UID_MIN-1).

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

	   The default value for UID_MIN (resp.  UID_MAX) is 1000 (resp. 60000).

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

	   useradd and newusers use this mask to set the mode of the home directory they create

	   It is also used by login to define users' initial umask. Note that this mask can be overridden by the user's GECOS line (if QUOTAS_ENAB
	   is set) or by the specification of a limit with the K identifier in limits(5).

       USERGROUPS_ENAB (boolean)
	   Enable setting of the umask group bits to be the same as owner bits (examples: 022 -> 002, 077 -> 007) for non-root users, if the uid
	   is the same as gid, and username is the same as the primary group name.

	   If set to yes, userdel will remove the user's group if it contains no more members, and useradd will create by default a group with the
	   name of the user.

FILES

       /etc/passwd
	   User account information.

       /etc/shadow
	   Secure user account information.

       /etc/group
	   Group account information.

       /etc/gshadow
	   Secure group account information.

       /etc/default/useradd
	   Default values for account creation.

       /etc/skel/
	   Directory containing default files.

       /etc/login.defs
	   Shadow password suite configuration.

EXIT VALUES

       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 already in use

       10
	   can't update group file

       12
	   can't create home directory

       14
	   can't update SELinux user mapping

SEE ALSO

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

shadow-utils 4.1.5.1						    05/25/2012								USERADD(8)