rtorrentto download only during certain time intervals, e.g. non-peak periods of some ISP, you don't need a cron job. Instead you can use the built-in scheduling functionality. To only download between 2 am and 8 am every night, add to your
schedule = throttle_start,02:00:00,24:00:00,"d.multicall=,d.start=" schedule = throttle_stop,08:00:00,24:00:00,"d.multicall=,d.stop="