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           useradd [options] LOGIN
           useradd -D
           useradd -D [options]


           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).


           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. The BASE_DIR must exist otherwise the
               home directory cannot be created.
               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 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 parent
               directory of HOME_DIR must exist otherwise the home directory
               cannot be created.
           -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.
               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
               If this option is not set, the skeleton directory is defined by the
               SKEL variable in /etc/default/useradd or, by default, /etc/skel.
           -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
               Note: -K UID_MIN=10,UID_MAX=499 doesn?t work yet.
           -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
           -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.
               specified) is defined by the USERGROUPS_ENAB variable in
           -o, --non-unique
               Allow the creation of a user account with a duplicate (non-unique)
               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
           -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
               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.
           -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.
           -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
               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.


           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).


           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
           Usernames may only be up to 32 characters long.


           The following configuration variables in /etc/login.defs change the
           behavior of this tool:
               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.
           SYS_UID_MAX (number), SYS_UID_MIN (number)
               Range of user IDs used for the creation of system users by useradd
               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
               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.


               User account information.
               Secure user account information.
               Group account information.
               Secure group account information.
               Default values for account creation.
               Directory containing default files.
               Shadow password suite configuration.


           The useradd command exits with the following values:
               can't update password file
               invalid command syntax
               invalid argument to option
               can't create mail spool
               can't update SELinux user mapping


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

    System Management Commands 07/24/2009 USERADD(8)


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