Inotify provides a nifty C API to monitor files and directories. The API hooks into your kernel and responding to events on your filesystem is much more efficient than doing something like writing a cron job to check for changes in a directory every minute. Fortunately, if you’re not a C developer, there is a package called inotify-tools that comes with two programs, inotifywait and inotifywatch. The difference is inotifywait waits for changes and inotifywatch gathers filesystem access statistics.