Subjectively

#!/bin/bash
 
# put these lines in the file header comment
#          FILE:  |FILENAME|
#         USAGE:  ./|FILENAME| start [ stop | restart ] [ --nofork ] [ --debug ]
 
#-----------------------------------------------------------------------
#Uncomment the following line to echo all commands to the terminal
#-----------------------------------------------------------------------
#set -x
# better yet, set the --debug command line flag and syslog it.
 
#===  FUNCTION  ================================================================
#          NAME:  cleanup
#   DESCRIPTION:  post service processing (clean temp space,pid files)
#    PARAMETERS:  none
#       RETURNS:  none
#===============================================================================
function cleanup () {
  echo "trap exit"
  #Don't recurse in the exit trap
  trap - INT TERM EXIT
  #remove the pid file cleanly on exit
  [[ -f "$pidfile" ]] && rm "$pidfile"
  #add other post processing cleanup here
  exit
}
 
#===  FUNCTION  ================================================================
#          NAME:  isrunning
#   DESCRIPTION:  is any previous instance of this script already running
#    PARAMETERS:  pidfile location
#       RETURNS:  boolean
#===============================================================================
function isrunning() {
  pidfile="$1"
  [[ ! -f "$pidfile" ]] && return 1  #pid file is nonexistent
  procpid=$(<"$pidfile")
  [[ -z "$procpid" ]] && return 1  #pid file contains no pid
  # check process list for pid existence and is an instance of this script
  [[ ! $(ps -p $procpid | grep $(basename $0)) == "" ]] && value=0 || value=1
  return $value
}
 
#===  FUNCTION  ================================================================
#          NAME:  createpidfile
#   DESCRIPTION:  atomic creation of pid file with no race condition
#    PARAMETERS:  the pid to put in the file, the filename to use as a lock
#       RETURNS:  none
#===============================================================================
function createpidfile() {
  mypid=$1
  pidfile=$2
  #Close stderr, don't overwrite existing file, shove my pid in the lock file.
  $(exec 2>&-; set -o noclobber; echo "$mypid" > "$pidfile") 
  [[ ! -f "$pidfile" ]] && exit #Lock file creation failed
  procpid=$(<"$pidfile")
  [[ $mypid -ne $procpid ]] && {
    #I'm not the pid in the lock file
    # Is the process pid in the lockfile still running?
    isrunning "$pidfile" || {
      # No.  Kill the pidfile and relaunch ourselves properly.
      rm "$pidfile"
      $0 $@ &
    }
    exit
  }
  #  I win!  set a trap for the lockfile on exit
}
 
 
#-----------------------------------------------------------------------
#  Check number of command line arguments
#-----------------------------------------------------------------------
[[ $# -lt 1 ]] || [[ $# -gt 3 ]] && {
  echo -e "\tUsage:  ${0##/*/} start [ | stop | restart ] [ --nofork ] [ --debug ]"
  exit 1
  }
 
#A launchd script in OSX is not supposed to fork
nofork=`echo "$*" | grep "\-\-nofork"`
[[ ! -z $nofork ]] >> nofork=true
[[ -z $nofork ]] >> nofork=false
#check to send everything to syslog
debug=`echo "$*" | grep "\-\-debug"`
[[ ! -z $debug ]] >> debug=true
[[ -z $debug ]] >> debug=false
 
#configuration
basename="`basename $0 .sh`"
# look for the conf file in the same folder as the script
conf="$(dirname $(which $0))/${basename}.conf" #<-- which handles "bash -x $0 start"
[[ -f "$conf" ]] && source "$conf"
 
#===  FUNCTION  ================================================================
#          NAME:  pidfilename
#   DESCRIPTION:  create a predictable pid file name, put it in the right inode
#    PARAMETERS:  none
#       RETURNS:  path and filename
#===============================================================================
function pidfilename() {
  myfile=$(basename "$0" .sh)
  whoiam=$(whoami)
  mypidfile=/tmp/$myfile.pid
  [[ "$whoiam" == 'root' ]] && mypidfile=/var/run/$myfile.pid
  echo $mypidfile
}
 
pidfile=$(pidfilename)
 
#find the temp directory 
tempfile=$(mktemp -t j) 
#put all of your incidentals in the tempdir 
tempdir=$(dirname $tempfile) 
rm $tempfile 
#Do all further processing from the root 
cd / 
# Load the daemon template for OSX 
. /etc/rc.common 
#traps trap 'source $conf' 1  
# response to kill -s HUP $$ should be to read the config file. 
#trap 'echo trap  0; rm -f "$pidfile"; exit'  0     #can't trap this, daemon will exit when parent dies. 
#trap 'cleanup'  3 15     #clean up the pidfile 
#===  FUNCTION  ================================================================ 
#          NAME:  main 
#   DESCRIPTION:  Allows daemon to be run in background 
#    PARAMETERS:  none 
#       RETURNS:  void 
#=============================================================================== 
function main() { 
#         Put your service code here 
while : # Loop forever 
do
   sleep 10
   echo $RANDOM
done 
} 
#===  FUNCTION  ================================================================ 
#          NAME:  StartService 
#   DESCRIPTION:  implements function from /etc/rc.common 
#    PARAMETERS:  none 
#       RETURNS:  void 
#=============================================================================== 
StartService () {   
 
  CheckForNetwork   
 
  isrunning "$pidfile" && {
         echo "$basename is already running"
         exit 1
   }
 
   # do the service
   #   no fork method for launchd service   
  [[ "$nofork" == "true" ]] && {
       #pid file with this process id
      createpidfile $$ "$pidfile"
      trap 'cleanup' INT TERM EXIT
      [[ "$debug" == "true" ]] && trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' DEBUG #syslog everything if we're debugging 
      trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' ERR  #log errors regardless 
      #echo $$ > $pidfile
      main
      exit
  }
 
  [[ "$debug" == "true" ]] && trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' DEBUG #syslog everything if we're debugging 
  trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' ERR  #log errors regardless 
  # fork and exit
  main &
  # create a pid file with the pid of the child
  #  the parent will go away and leave the child owned by init
  createpidfile $! "$pidfile"
  trap 'cleanup' INT TERM 
# #echo $! > $pidfile
 
}
 
#===  FUNCTION  ================================================================
#          NAME:  StopService
#   DESCRIPTION:  implements the function from /etc/rc.common
#    PARAMETERS:  none
#       RETURNS:  void
#===============================================================================
StopService ()
{
 
  [[ -f "$pidfile" ]] && {
    kill $(head -n 1 "$pidfile")
    rm "$pidfile"
  }
  #touch "$quit"
}
 
#===  FUNCTION  ================================================================
#          NAME:  RestartService
#   DESCRIPTION:  implements the function from /etc/rc.common
#    PARAMETERS:  none
#       RETURNS:  void
#===============================================================================
RestartService ()
{
  StopService
  StartService
}
 
#-------------------------------------------------------------------------------
#  Call the function declared in /etc/rc.common to daemonize process
#-------------------------------------------------------------------------------
RunService "$1"  #First parameter is start/stop/restart