This week’s command is: useradd.

This command is used to add new users to your linux system. The syntax is as follows:
useradd [options] [user]

The following was taken from a great site for learning about linux commands(ss64.com) and will further explain the command:

OPTIONS
-c comment Comment field.

-d dir Home directory.
The default is to use user as the directory name
under the home directory specified with the -D option.

-e date Account expiration date.
date is in the format MM/DD/YYYY.
Two-digit year fields are also accepted.
The value is stored as the number of days since January 1, 1970.
This option requires the use of shadow passwords.

-f days Permanently disable account this many days after the
password has expired. A value of -1 disables this feature.
This option requires the use of shadow passwords.

-g group Initial group name or ID number.
If a different default group has not been specified using the -D option,
the default group is 1.
-G groups Supplementary groups given by name or number in a comma-separated
list with no whitespace.

-k [dir] Copy default files to user’s home directory.
Meaningful only when used with the -m option.
Default files are copied from /etc/skel/ unless an alternate dir is specified.

-m Make user’s home directory if it does not exist.
The default is not to make the home directory.

-o Override. Accept a nonunique uid with the -u option. (Probably a bad idea.)

-s shell Login shell.

-u uid Numerical user ID. The value must be unique unless the -o option is used.
The default value is the smallest ID value greater than 99 and greater
than every other uid.

-D [options] Set or display defaults. If options are specified, set them.
If no options are specified, display current defaults. The options are:

-b dir Home directory prefix to be used in creating home directories.
If the -d option is not used when creating an account, the
user name will be appended to dir.

-e date Expire date. Requires the use of shadow passwords.

-f days Number of days after a password expires to disable an account.
Requires the use of shadow passwords.

-g group Initial group name or ID number.

-s shell Default login shell.