用php中的inotify读取linux中的文件

I need to read a file in linux when changes are made to it and output the contents of the file to php. I read about inotify and i think it's the one i'm looking for. I don't understand it well. do i need to install inotify in linux so i can use inotify in php?.. if possible can you show me a quick example of how i use it in php for reading/tailing a file in php for events that occured in the file?.

Thanks,

You can use shell/bash in PHP:

$shell = shell_exec("cat file");
print $shell