I grabbed Syncthing from Syncthing (R6x86) — RNXtras.com. Unfortunately it runs as root so here is how you can change that:
I’ll be using the admin user for this example but you can substitute this out for a different user as long as that user has read/write for all the data you want to sync.
Stop the Syncthing app via your ReadyNas admin page
SSH into your ReadyNas and ensure all the Syncthing files can be accessed by your user
sudo chown -Rv admin: /apps/syncthing/conf/*
Now we need to change the startup user and group
sudo nano /etc/init.d/syncthing
Scroll down and change #Permissions to
# Permissions USER=admin GROUP=admin
If you don’t have nano run
sudo apt install nano -y
Start the Syncthing app via your ReadyNas admin page If it doesn’t start run
tail -t /var/log/syncthing.log
and stop / start the app again via your admin page to see what error might be causing it not to start.