Section: System Management Commands (8)
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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
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 default.
The options which apply to the
- -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 name.
- -b, --base-dir BASE_DIR
The default base directory for the system if
dir is not specified.
is concatenated with the account name to define the home directory. If the
option is not used,
- -d, --home HOME_DIR
The new user will be created using
as the value for the user's login directory. The default is to append the
and use that as the login directory name. The directory
does not have to exist but will not be created if it is missing.
- -e, --expiredate EXPIRE_DATE
The date on which the user account will be disabled. The date is specified in the format
- -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 existing group.
- -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
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 dirs.
- -m, --create-home
The user's home directory will be created if it does not exist. The files contained in
will be copied to the home directory if the
option is used, otherwise the files contained in
will be used instead. Any directories contained in
will be created in the user's home directory as well. The
option is only valid in conjunction with the
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).
can be used when creating system account to turn off password ageing, even though system account has no password at all. Multiple
options can be specified, e.g.:
doesn't work yet.
- -o, --non-unique
Allow the creation of a user account with a 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 shell.
- -u, --uid UID
The numerical value of the user's ID. This value must be unique, unless the
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.
- -Z, --selinux-user SEUSER
The SELinux user for the user's login. The default is to leave this field blank, which causes the system to select the default SELinux user.
Changing the default values
When invoked with the
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
to create the new directory name if the
option is not used when creating a new account.
- -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 entry.
- -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,
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 a NIS group. This must be performed on the NIS server.
Similarly, if the username already exists in an external user database such as NIS,
will deny the user account creation request.
User account information.
Secure user account information.
Group account information.
Secure group account information.
Default values for account creation.
Directory containing default files.
Shadow password suite configuration.
command exits with the following values:
can't update password file
invalid command syntax
invalid argument to option
UID already in use (and no
specified group doesn't exist
username already in use
can't update group file
can't create home directory
can't create mail spool
- Changing the default values
- EXIT VALUES
- SEE ALSO
linux.jgfs.net manual pages