useradd – Create a new user or update default new user information

USAGE
       useradd [-c comment] [-d home_dir]
               [-e expire_date] [-f inactive_time]
               [-g initial_group] [-G group[,...]]
               [-m [-k skeleton_dir] | -M] [-n] [-o] [-p passwd] [-r] [-l]
               [-s shell] [-u uid] login

       useradd -D [-g default_group] [-b default_home]
               [-e default_expire_date] [-f default_inactive]
               [-s default_shell]

DESCRIPTION
   Creating New Users
       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.  The new user account will be entered
       into the system files as needed, the home directory  will  be  created,
       and  initial  files copied, depending on the command line options.  The
       version provided with Red Hat Linux will create a group for  each  user
       added  to the system, unless the -n option is given.  The options which
       apply to the useradd command are:

       -c comment
              The new user’s password file comment field.

       -d 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 default_home and use that as the login directory name.

       -e expire_date
              The date on which the user account will be disabled.   The  date
              is specified in the format YYYY-MM-DD.

       -f inactive_days
              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 fea-
              ture.  The default value is -1.

       -g initial_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 group,[...]
              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.

       -m     The  user’s home directory will be created if it does not exist.
              The files contained in skeleton_dir will be copied to  the  home
              directory  if  the  -k  option is used, otherwise the files con-
              tained in /etc/skel will be used instead.  Any directories  con-
              tained  in  skeleton_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.

       -M     The user home directory will not be created, even if the  system
              wide settings from /etc/login.defs is to create home dirs.

       -n     A group having the same name as the user being added to the sys-
              tem will be created by default. This option will turn  off  this
              Red Hat Linux specific behavior.

       -o     Allow create user with duplicate (non-unique) UID.

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

       -r     This flag is used to create a system account. That  is,  a  user
              with   a  UID  lower  than  the  value  of  UID_MIN  defined  in
              /etc/login.defs and whose password does not  expire.  Note  that
              useradd  will  not  create  a  home  directory for such an user,
              regardless of the default setting in /etc/login.defs.  You  have
              to  specify  -m option if you want a home directory for a system
              account to be created.  This is an option added by Red Hat.

       -l     Do not add the user to the last  login  log  file.  This  is  an
              option added by Red Hat.

       -s 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 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 99 and greater than every other user.  Values between 0 and
              99 are typically reserved for system accounts.

   Changing the default values
       When  invoked  with the -D option, useradd will either display the cur-
       rent default values, or update the  default  values  from  the  command
       line.  The valid options are

       -b default_home
              The  initial  path  prefix for a new user’s home directory.  The
              user’s name will be affixed to the end of default_home to create
              the  new directory name if the -d option is not used when creat-
              ing a new account.

       -e default_expire_date
              The date on which the user account is disabled.

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

       -g default_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 default_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.
       This version of useradd was  modified  by  Red  Hat  to  suit  Red  Hat
       user/group conventions.

CAVEATS
       You  may not add a user to an NIS group.  This must be performed on the
       NIS server.

FILES
       /etc/passwd - user account information
       /etc/shadow - secure user account information
       /etc/group - group information
       /etc/gshadow - secure group information
       /etc/default/useradd - default information
       /etc/login.defs - system-wide settings
       /etc/skel - directory containing default files

SEE ALSO
       chfn(1), chsh(1), passwd(1), crypt(3), groupadd(8), groupdel(8), group-
       mod(8), userdel(8), usermod(8)

AUTHOR
       Julianne Frances Haugh (jockgrrl@ix.netcom.com)