useradd

> man newusers
> ====================
> NAME
>        newusers - update and create new users in batch

> SYNOPSIS
>        newusers [ new_users ]

> DESCRIPTION
>        newusers  reads a file of user name and cleartext password
>        pairs and uses this  information  to  update  a  group  of
>        existing  users  or  to create new users.  Each line is in
>        the  same  format  as  the  standard  password  file  (see
>        passwd(5)) with the following exceptions.

> NAME
>        chpasswd - update password file in batch

> SYNOPSIS
>        chpasswd

> DESCRIPTION
>        chpasswd  reads a file of user name and cleartext password
>        pairs from standard input and  uses  this  information  to
>        update  a  group  of  existing users.  Each line is of the
>        format

>               user_name:password

>        The named user must exist.  The supplied password will  be
>        encrypted and the password age updated, if present.

>        This  command  is  intended  to  be used in a large system
>        environment where many accounts are created  at  a  single
>        time.