Here is my solution for Linux distributions using Upstart 1.4 and higher.
Save the contents below into a configuration file under /etc/init, for example: /etc/init/db_user.conf:
# Dropbox upstart script for user db_user, db_user can be replaced by anything you like.
description "Dropbox db_user"
author "myth384"
start on runlevel [2345]
stop on runlevel [!2345]
respawn
setuid db_user
# The next two lines are optional. I use these to be able to share the
# Dropbox using Samba. Within group shareusers are all Samba users.
# setgid shareusers
# umask 0002
# The next line is necessary to be able to synchronise files with non-ASCII characters.
env LANG="en_US.UTF-8"
exec /home/db_user/.dropbox-dist/dropbox
To start up the daemon without rebooting:
sudo start db_user
NOTE: By uncommenting the setgid line it is not necessary to set the setgid flag on the .dropbox.cache folder as indicated by other sources on the internet.
