Useradd

Manpage

NAME

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

SYNOPSIS

useradd [-c comment] [-d home_dir] [-e expire_date] [-f inactive_days] [-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. 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. The version provided with Red Hat Linux will create a group for each user added to the system, unless the -n option is given.

OPTIONS

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 feature. 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 not be created, even if the system wide settings from /etc/login.defs is to create home dirs.
-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 contained in /etc/skel will be used instead. Any directories contained 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.
-n	A group having the same name as the user being added to the system 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 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 default_home	The initial path prefix for a new userÃ¢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 creating 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 userÃ¢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

EXIT VALUES

The useradd command exits with the following values:

- success

- can't update password file

- invalid command syntax

- invalid argument to option

- uid already in use (and no -o)

- specified group doesnÃ¢t exist

- username already in use

- can't update group file

- can't create home directory

- can't create mail spool

AUTHOR

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

Edit Log

2005-09-14: Copied from Red Hat Fedora Core 4 manpage. Need to compare to some non-RedHat distro to see which bits are RedHat-only and mark them as such.