The mysql_install_db script creates the server's data directory, initializes the mysql database that contains the grant tables, and creates an empty test database. mysql_install_db populates the grant tables with initial accounts for the root and anonymous users. See Chapter 11, "General MySQL Administration," for details on these accounts and how to secure your installation by establishing passwords.
mysql_install_db is unavailable on Windows, but unnecessary because Windows distributions include preinitialized mysql and test databases.
Options Specific to mysql_install_db
You can use the options mentioned in this section on the command line, and you can set the values for many of them by placing appropriate entries in the [mysqld] group of an option file. The script also reads the [mysql_install_db] option group, which is more useful for options such as --ldata and --force that are understood only by mysql_install_db and not by mysqld.