I used screen. Just start a screen session for it like "music-downloads" and then you can quit the session and exit out OR install a DE like XFCE on your server and then use something like xfreerdp to remote desktop in, run the script in a terminal on the server, then just close your xfreerdp.

I first used screen to download everything but then decided to install XFCE and Nicotine+ and just leave it up so people can download from my library also.