I need to run a php script as daemon process (wait for instructions and do stuff). cron job will not do it for me because actions need to be taken as soon as instruction arr
I run a large number of PHP daemons.
I agree with you that PHP is not the best (or even a good) language for doing this, but the daemons share code with the web-facing components so overall it is a good solution for us.
We use daemontools for this. It is smart, clean and reliable. In fact we use it for running all of our daemons.
You can check this out at http://cr.yp.to/daemontools.html.
EDIT: A quick list of features.