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useradd - Create a new user or update default new user information
useradd [options] LOGIN
useradd -D [options]
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:
- -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
- -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.
- -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
- -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.
- The user’s home directory will not be created, even if the
system wide settings from /etc/login.defs is to create home
- -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.
- 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.
- -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.
- -o, --non-unique
Allow create user account with duplicate (non-unique) UID.
- -p, --password PASSWORD
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
- -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
- -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 HOME_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
- -e EXPIRE_DATE
The date on which the user account is disabled.
- -f 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
- -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
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
You may not add a user to a NIS group. This must be performed on the
Similarly, if the username already exists in an external user database
such as NIS, useradd will deny the user account creation request.
user account information
secure user account information
group account information
secure group information
directory containing default files
shadow password suite configuration
The useradd command exits with the following values:
- can’t update password file
- invalid command syntax
- invalid argument to option
- UID already in use (and no -o)
- specified group doesn’t exist
- username already in use
- can’t update group file
- can’t create home directory
- can’t create mail spool
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