useradd - Create a new user or update default new user information
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]
[-s shell] [-u uid] login
useradd -D [-g default_group] [-b default_home]
[-e default_expire_date] [-f default_inactive]
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:
The new user's password file comment field.
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.
The date on which the user account will be disabled. The date is specified in the
The number of days after a password expires until the account is permanently dis-
abled. 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 existing group. The default group
number is 1 or whatever is specified in /etc/default/useradd.
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 con-
tained 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 direc-
tories 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.
-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 specific behavior.
-o Allow create user with duplicate (non-unique) UID.
The encrypted password, as returned by crypt(3). The default is to disable the
-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
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 small-
est 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 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 default_home to create the new directory name if the -d
option is not used when creating a new account.
The date on which the user account is disabled.
The number of days after a password has expired before the account will be dis-
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 .
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.
The system administrator is responsible for placing the default user files in the
This version of useradd was modified by Red Hat to suit Red Hat user/group conventions.
You may not add a user to an NIS group. This must be performed on the NIS server.
/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
chfn(1), chsh(1), passwd(1), crypt(3), groupadd(8), groupdel(8), groupmod(8), userdel(8),
Julianne Frances Haugh (firstname.lastname@example.org)