note 54803 added to function.shell-exec

Here is an example of how you can execute a command in background an get the Process ID created by *NIX, for future reference or monitoring. <?php //Run linux command in background and return the PID created by the OS function run_in_background($Command, $Priority = 0) { if($Priority) $PID = shell_exec("nohup nice -n $Priority $Command > /dev/null & echo $!"); else $PID = shell_exec("nohup $Command > /dev/null & echo $!"); return($PID); } ?> There is also a trick which I use to track if the background task is running using the returned PID <?php //Verifies if a process is running in linux function is_process_running($PID) { exec("ps $PID", $ProcessState); return(count($ProcessState) >= 2); } ?> I commonly use both functions in combination to batch copy big mysql tables in background and wait for the copy process to finish sending chunks to the client browser in the following way: <?php $CopyTaskPid = run_in_background("mysql --user=backup_user --password=backup_user_password --execute='INSERT INTO backup-db.table SELECT * FROM online-db.table'", "+20"); while(is_process_running($CopyTaskPid)) { echo "."; ob_flush(); flush(); sleep(2); } ?> ---- Manual Page -- http://www.php.net/manual/en/function.shell-exec.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+54803 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+54803&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+54803&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+54803&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+54803&report=yes&reason=useless Delete: non-english -- http://master.php.net/manage/user-notes.php?action=delete+54803&report=yes&reason=non-english Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+54803&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+54803&report=yes Search -- http://master.php.net/manage/user-notes.php