php bin/magento --version

composer config repositories.magento composer https://repo.magento.com
composer require magento/data-migration-tool:<version>

composer config repositories.magento composer https://repo.magento.com
composer require magento/data-migration-tool:2.1.2

<source>
<database host="localhost" name="Magento1-DB-name" user="DB-username" password="DB-password"/>
</source>
<destination>
<database host="localhost" name="Magento2-DB-name" user="DB-username" password="DB-password"/>
</destination>
<options>
<crypt_key>Magento1-Encrypted-Key</crypt_key>
</options>

php bin/magento migrate:settings --reset <path to your config.xml>

php bin/magento migrate:data --reset <path to your config.xml>

https://www.ubertheme.com/magento-extensions-2-x/magento-2-data-migration-tool/