upstart-udev-bridge --help
Usage: upstart-udev-bridge [OPTION]...
Bridge udev events into upstart

Options:
      --daemon                Detach and run in the background
      --no-strip              Do not strip non-printable bytes from udev
                                message data
      --user                  Connect to user session
  -q, --quiet                 reduce output to errors only
  -v, --verbose               increase output to include informational messages
      --help                  display this help and exit
      --version               output version information and exit

By default, upstart-udev-bridge does not detach from the console and remains in
the foreground.  Use the --daemon option to have it detach.

Report bugs to <upstart-devel@lists.ubuntu.com>