Question

I would like to have a shell scipt that runs infinitely and keeps checking status of a php script (say my.php) and restarts it if the script has terminated somehow. I have the idea to go for –

ps -aux | grep "my.php"

and then use the result of this to check the status and do accordingly. Thanks in advance.

Answer 1

You can simply say:

ps -aux | grep -q "my.php" || php -f my.php

The way it works is that grep -q will not output anything but will return an “OK” exit code if it found something. when it returns a “NOT OK” exit code, the part after the || (“or”) gets executed (because of boolean short-circuit evaluation – look it up).

You also need to make sure that:

1. you run the new script in the background and detach it from your console so that your script can keep monitoring

2. when you run ps | grep sometimes ps also lists your grep and then the grep “greps itself”, so you have to filter that out.

It should look something like this:

while true
    ps -aux | grep -v grep | grep -q "my.php" || ( nohup php -f "my.php" & )
    sleep 1
done

or some-such..