Re: How to determine if a script instance is already running?

* Matt <datahead4@gmail.com> : > Perhaps "svscan" and its associated "daemontools" programs could be > used to monitor the script instead of relying on cron. Just a note: The above suggestion would assume you control the box, and that you're running on a *nix system (i.e., you've got root on a linux, bsd, solaris, AIX, etc. server). > On 8/2/05, André Medeiros <andre.caum@gmail.com> wrote: > > On Tue, 2005-08-02 at 15:09 +0100, Stut wrote: > > > André Medeiros wrote: > > > > Do like some services do: > > > > > > > > 1) Check if script.pid exists > > > > 2) If it doesn't > > > > 2.1) Write the process's PID onto the file > > > > (http://pt.php.net/manual/en/function.getmypid.php) > > > > 3) If it does > > > > 3.1) Die gracefully :) > > > > > > Personally I'd extend that slightly to have the process touch the PID > > > file every so often and to check that it's been touched recently when it > > > starts up. Alternatively use the ps shell command to check that a > > > process with that PID is still running, but that tends to be less reliable. > > > > > > If the process does decide to continue in spite of the PID file existing > > > it should issue a a shell kill command to kill that PID in case it's > > > hung or a zombie. > > > > > > -Stut > > > > Excelent point! -- Matthew Weier O'Phinney Zend Certified Engineer http://weierophinney.net/matthew/