TYPO3/Extbase/Security/FeUser.php
public static function getUser($key = null)
    {
        if (null == $key) {
            return $GLOBALS['TSFE']->fe_user->user;
        } else {
            return (isset($GLOBALS['TSFE']->fe_user->user[$key])) ? $GLOBALS['TSFE']->fe_user->user[$key] : false;
        }

    }
public static function getUser($key = null)
    {
        if (null == $key) {
            return $GLOBALS['TSFE']->fe_user->user;
        } else {
            return (isset($GLOBALS['TSFE']->fe_user->user[$key])) ? $GLOBALS['TSFE']->fe_user->user[$key] : false;
        }

    }
public static function getUser ( $ key = null ) { if ( null == $ key ) { return $ GLOBALS [ 'TSFE' ] -> fe_user -> user ; } else { return ( isset ( $ GLOBALS [ 'TSFE' ] -> fe_user -> user [ $ key ] ) ) ? $ GLOBALS [ 'TSFE' ] -> fe_user -> user [ $ key ] : false ; } }
Returns fe_user data

@param null $key - If null you get the whole user data array
@return mixed - false if key not exists
Returns fe_user data