"C:\Program Files\CloudCompare\CloudCompare" -AUTO_SAVE OFF -o C:\CloudComparetest\r02.las -C_EXPORT_FMT E57 -SAVE_CLOUDS % ---WHERE CAN I ADD NAME OF FILE---%
For now there's no option to specify the output filename in the command line tool of CloudCompare. You can only choose whether the timestamp should be added or not (see the -NO_TIMESTAMP option).