When invoked without the \fB\-D\fR option, the \fBuseradd\fR 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\&.
.SH"OPTIONS"
.PP
The options which apply to the \fBuseradd\fR command are:
.TP
\fB\-c\fR\fIcomment\fR
The new user's password file comment field\&.
.TP
\fB\-d\fR\fIhome_dir\fR
The new user will be created using \fI home_dir \fRas the value for the user's login directory\&. The default is to append the \fIlogin\fR name to \fIhome\fR and use that as the login directory name\&.
.TP
\fB\-e\fR\fIexpire_date\fR
The date on which the user account will be disabled\&. The date is specified in the format \fIYYYY\-MM\-DD\fR\&.
.TP
\fB\-f\fR\fIinactive_days\fR
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\&.
.TP
\fB\-g\fR\fIinitial_group\fR
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 \fI/etc/default/useradd\fR\&.
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 \fB\-g\fR option\&. The default is for the user to belong only to the initial group\&.
.TP
\fB\-M\fR
RedHat added the CREATE_HOME option in login\&.defs in their version of shadow\-utils (which makes \-m the default, with new \-M option to turn it off)\&. Unfortunately, this changes the way useradd works (it can be run by scripts expecting some standard behaviour), compared to other Unices and other Linux distributions, and also adds a lot of confusion\&.
.TP
\fB\-m\fR
The user's home directory will be created if it does not exist\&. The files contained in \fIskeleton_dir\fR will be copied to the home directory if the \fB\-k\fR option is used, otherwise the files contained in \fI/etc/skel\fR will be used instead\&. Any directories contained in \fI skeleton_dir\fR or \fI/etc/skel\fR will be created in the user's home directory as well\&. The \fB\-k\fR option is only valid in conjunction with the \fB\-m\fR option\&. The default is to not create the directory and to not copy any files\&.
.TP
\fB\-o\fR
Allow create user with duplicate (non\-unique) UID\&.
.TP
\fB\-p\fR\fIpasswd\fR
The encrypted password, as returned by \fBcrypt\fR(3)\&. The default is to disable the account\&.
.TP
\fB\-s\fR\fIshell\fR
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\&.
.TP
\fB\-u\fR\fIuid\fR
The numerical value of the user's ID\&. This value must be unique, unless the \fB\-o\fR 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\&.
.SS"Changing the default values"
.PP
When invoked with the \fB\-D\fR option, \fBuseradd\fR will either display the current default values, or update the default values from the command line\&. The valid options are
.TP
\fB\-b\fR\fIhome_dir\fR
The initial path prefix for a new user's home directory\&. The user's name will be affixed to the end of \fIhome\fR to create the new directory name if the \fB\-d\fR option is not used when creating a new account\&.
.TP
\fB\-e\fR\fIexpire_date\fR
The date on which the user account is disabled\&.
.TP
\fB\-f\fR\fIinactive\fR
The number of days after a password has expired before the account will be disabled\&.
.TP
\fB\-g\fR\fIgroup\fR
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 \&.
.TP
\fB\-s\fR\fIshell\fR
The name of the new user's login shell\&. The named program will be used for all future new user accounts\&.
.PP
If no options are specified, \fBuseradd\fR displays the current default values\&.
.SH"NOTES"
.PP
The system administrator is responsible for placing the default user files in the \fI/etc/skel/\fR directory\&.
.SH"CAVEATS"
.PP
You may not add a user to an NIS group\&. This must be performed on the NIS server\&.
.SH"FILES"
.TP
\fI/etc/passwd\fR
user account information
.TP
\fI/etc/shadow\fR
secure user account information
.TP
\fI/etc/group\fR
group account information
.TP
\fI/etc/default/useradd\fR
default information
.TP
\fI/etc/skel/\fR
directory containing default files
.SH"EXIT VALUES"
.PP
The \fBuseadd\fR command exits with the following values: