daemon mode -- background mode 구현

[PHP]

-- example.php --------------------------------------------
#!/usr/local/bin/php -q
<?php
## -F : run main process in foreground, default background
## -p PIDFILE, -u USER, -m MAXCONNECTION
##
$opt = getopt('Fp:u:m:');

echo 'PPID:'.getmypid()."\n"; // parent PID, debug mode

if(!isset($opt['F'])) // is mean that backgrund mode
{
  $pid = pcntl_fork();

  ## fork(2) -- man 2 fork
  ## -1(fork fail), 0(child), other(parent)
  ##
  if($pid == -1)
  {
	echo 'fork fail'."\n"; // some write to error_log file
	exit;
  }
  else if($pid != 0) exit; // is parent pid

  echo 'PID:'.getmypid()."\n"; // child PID, debug mode
}

while(1)
{
 ...
}

exit;
?>
-----------------------------------------------------------

[Born-SHELL]

-- example.sh ---------------------------------------------
#!/bin/sh

_main()
{
  while [ 1 ] ; do
	...
  done
}

_main &

exit 0
-----------------------------------------------------------