General Information
If you want to run a command, process or whatever via SSH directly and move it to the background attach to it later again, screen is what you need.
Installation
apt-get install screen
Usage
Start screen with command screen
Inside that screen, start your process like you allways do. You detach from that screen with CTRL+A then hit D.
The screen now runs in the background, you can even drop off your SSH connection.
Once you reconnect via SSH and want to reconnect to your screen, simply type in screen -r If there's more then one intance of screen running, you will get notified that there are multiple instances running and you need to specificy which instance you want to resume. You can also pull up that list by typing in screen -list. You can resume the screen you want by typing screen -r <id_from_list>.
Greetings
David