Register your hook class in local configuration (ext_localconf.php):

` $GLOBALS ['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_tcemain.php']['processDatamapClass'][''] = 'NXS\NxsReferenzen\Hook\TCEmainHook';

$GLOBALS ['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_tcemain.php']['processCmdmapClass'][''] = 'NXS\NxsReferenzen\Hook\TCEmainHook';`

Ensure your hook class has namespace declaration: `

'; var_dump($command); echo '

';
        die();
    }
}

`