How can I constantly monitor (small) file for changes?
Eg. when file is updated (action from web application), a script is executed (if not already running).
Right now, I do it every minute using cron, but this has delay up to one minute. I'd like to take the action immediately after the file is changed.
Maybe I need to write some low level process running in the background, once the server is started?
The reason I want to do it is to separate web application from root actions (performed on demand, once when file is updated).