tcl-inotify , an extension by Alexandros Stergiakis, provides a directory change notifications%|%file and directory change notification ] service for Linux.
tcl-inotify provides an interface to the inotify file system notification
Inotify is a Linux kernel subsystem that provides file system event notifications. It was written by John McCutchan with help from Robert Love and later Amy Griffis to replace dnotify. It was included in the mainline kernel from release 2.6.13, and could be compiled into 2.6.12 and possibly earlier releases by use of a patch. Its function is essentially an extension to filesystems to notice changes to the filesystem, and report those changes to applications.