Computer Science
USERADD(8) USERADD(8)
NAME
useradd - Create a new user or update default new user
information
SYNOPSIS
useradd [-c comment] [-d home_dir]
[-e expire_date] [-f inactive_time]
[-g initial_group] [-G group[,...]]
[-m [-k skeleton_dir] | -M] [-s shell]
[-u uid [ -o]] [-n] [-r] login
useradd -D [-g default_group] [-b default_home]
[-f default_inactive] [-e default_expire_date]
[-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 -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 dis-
abled. The date is specified in the format
MM/DD/YY.
-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.
-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 skele-
ton_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 cre-
ated 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 system will be created by default.
This option will turn off this Red Hat Linux spe-
cific behavior.
-r This flag is used to create a system account. That
is, an user with an UID lower than value of UID_MIN
defined in /etc/login.defs. 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.
-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 dis-
play 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 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 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 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 convention.
CAVEATS
You may not add a user to an NIS group. This must be per-
formed on the NIS server.
FILES
/etc/passwd - user account information
/etc/shadow - secure user account information
/etc/group - 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), groupadd(8), groupdel(8), groupmod(8),
passwd(1), userdel(8), usermod(8)
AUTHOR
Julianne Frances Haugh (jfh@tab.com)
1
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