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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 and 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.
OPTIONS
       The options which apply to the useradd command are:
       -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 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, --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
          missing.
       -e, --expiredate EXPIRE_DATE
          The date on which the user account will be disabled. The date is
          specified in the format YYYY-MM-DD.
       -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.
          The default value is -1.
       -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]]]
          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.
       -m, --create-home
          The user's home directory will be created if it does not exist. The
          files contained in SKEL_DIR will be copied to the home directory if
          the -k option is used, otherwise the files contained in /etc/skel
          will be used instead. Any directories contained in SKEL_DIR or
          /etc/skel will be created in the user's home directory as well. The
          -k option is only valid in conjunction with the -m option. The
          default is to not create the directory and to not copy any files.
          This option may not function correctly if the username has a / in
          it.
       -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.
          For the compatibility with previous Debian's useradd, the -O option
          is also supported.
       -o, --non-unique
          Allow the creation of a user account with a duplicate (non-unique)
          UID.
       -p, --password PASSWORD
          The encrypted password, as returned by crypt(3). The default is to
          disable the account.
       -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.
       -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 999 and greater
          than every other user. Values between 0 and 999 are typically
          reserved for system accounts.
   Changing the default values
       When invoked with the -D option, useradd will either display the
       current default values, or update the default values from the command
       line. The valid options are
       -b, --base-dir BASE_DIR
          The initial path prefix for a new user's home directory. The user's
          name will be affixed to the end of HOME_DIR to create the new
          directory name if the -d option is not used when creating a new
          account.
       -e, --expiredate EXPIRE_DATE
          The date on which the user account is disabled.
       -f, --inactive INACTIVE
          The number of days after a password has expired before the account
          will be disabled.
       -g, --gid GROUP
          The group name or ID for a new user's initial group. The named group
          must exist, and a numerical group ID must have an existing entry.
       -s, --shell SHELL
          The name of the new user's login shell. The named program will be
          used for all future new user accounts.
       If no options are specified, useradd displays the current default
       values.
NOTES
       The system administrator is responsible for placing the default user
       files in the /etc/skel/ directory.
CAVEATS
       You may not add a user to a NIS group. This must be performed on the
       NIS server.
       Similarly, if the username already exists in an external user database
       such as NIS, useradd will deny the user account creation request.
       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 an end of line ('0).
FILES
       /etc/passwd
          User account information.
       /etc/shadow
          Secure user account information.
       /etc/group
          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
       13
          can't create mail spool
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).

System Management Commands        02/27/2007                        USERADD(8)