So as not to saturate my (very limited) uplink when a torrent as finished downloading (using transmission-daemon on my Raspberry Pi) I wanted it to be removed automatically. There were a number of docs on the web about how to do this but here is a simple 2-line file that will do it:
#!/bin/bash transmission-remote -t $TR_TORRENT_ID -r
Save this as /usr/bin/torrent-complete.sh, chmod +x the script. Stop transmission-deamon (you need to do this rather than a restart as it always dumps the current live config on stop/restart so any changes you make while it is running will be nuked) Then open up /etc/transmission-daemon/settings.json and add (or modify) the following lines:
"script-torrent-done-enabled": true, "script-torrent-done-filename": "/usr/bin/torrent-complete.sh",
Start up transmission-deamon and there you go.