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

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!