There are several ways to do this, you can either use nohup, or append & at the end of command – personally, I’ve found forever to do the job perfectly fine.
Assuming you already have npm installed, if not, just do
sudo apt-get install npm
Then install forever
npm install forever --global
Now you can run it like this
forever start app.js
And it will take care of everything.
/usr/bin/env: node: No such file or directory
Can be fixed by creating symlink.
cd /usr/bin sudo ln -s nodejs node
View list of running nodejs apps in forever
root@ubuntu:/# forever list info: Forever processes running data: uid command script forever pid id logfile uptime data:  mqgC /usr/bin/nodejs app.js 29570 31398 /root/.forever/mqgC.log 0:1:25:6.344
To see logs for your application, do forever logs + ID of the app ( in our list it’s  – 0 )
root@ubuntu:/# forever logs 0 data: app.js:31398 - Node app is running on port 5000