Start arbitrary shell script as a background daemon from init.d

daemon.sh

#!/bin/sh

### BEGIN INIT INFO
# Provides:          scriptname
# Required-Start:    
# Required-Stop:     
# Default-Start:     2 3 4 5
# Default-Stop:      S 0 1 6
# Short-Description: Script short description
# Description:       Starts/Stops the script
### END INIT INFO

USER=root
PATH=/usr/bin:/usr/local/bin:/usr/local/sbin:/sbin:/bin:/usr/sbin
DESC="description"
NAME=script_name
DAEMON=/bin/$NAME
DAEMON_NAME=$NAME
LOGFILE=/var/log/script.log
# Or you can use
# LOGFILE=/dev/null
# to supress logging.
SCRIPTNAME=/etc/init.d/$NAME

case "$1" in
 start)
   echo -n "Starting $DESC: $NAME"
   su -c "daemon --user=$USER --name=$DAEMON_NAME --output=$LOGFILE --command=$DAEMON" root
   echo "."
   ;;
 stop)
   echo -n "Stopping $DESC: $NAME"
   su -c "daemon --user=$USER --name=$DAEMON_NAME --stop" root
   echo "."
   ;;
 *)
   echo "Usage: $SCRIPTNAME {start|stop}" >&2
   exit 1
   ;;
esac

exit 0