This one-liner checks the current sum of download speed of all torrents currently running in transmission-daemon. You can also direct the output to a file, to have a logfile of it.

As a depenency it needs the moreutils package, because it uses the ‘ts’ command for timestamping. It will also run until it’s aborted with Ctrl+C.

while [ 0 ]; do echo -n "Transmission download speed: " | ts "[%Y-%m-%d %H:%M:%S]"; transmission-remote -n zsiti:password -l | grep Sum | awk '{print $5}'| rev | cut -c 3- | rev; sleep 1; done