Can I use linuxsampler without a GUI as well?
Yes, but unfortunately there is no console based frontend for linuxsampler (yet). You have to write LSCP scripts and send it to the running linuxsampler application. But don’t worry, if you don’t know how to write LSCP scripts, you can also start by saving a sampler session with QSampler, because the session files qsampler writes are actually real LSCP scripts.