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 by
The options which apply to the useradd command are:
Any text string. It is generally a short description of the
login, and is currently used as the field for the user’s full
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.
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 date on which the user account will be disabled. The date is
specified in the format YYYY-MM-DD.
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.
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
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.
Display help message and exit.
The user’s home directory will not be created, even if the
system wide settings from /etc/login.defs is to 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.
Do not add the user to the last login log file. This is an
option added by Red Hat.
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. When this option is used,
users by default will be placed in whatever group is specified
in /etc/default/useradd. If no default group is defined, group 1
will be used.
Overrides /etc/login.defs defaults (UID_MIN, UID_MAX, UMASK,
PASS_MAX_DAYS and others).
Example: -KPASS_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,
Note: -KUID_MIN=10,UID_MAX=499 doesn’t work yet.
Allow create user account with duplicate (non-unique) UID.
The encrypted password, as returned by crypt(3)
. The default is
to disable the account.
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
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
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.
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
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
The date on which the user account is disabled.
The number of days after a password has expired before the
account will be disabled.
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
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