inotify (inode notify) is a Linux kernel subsystem created by John McCutchan, which monitors changes to the filesystem, and reports those changes to applications. It can be used to automatically update directory views, reload configuration files, log changes, backup, synchronize, and upload. The inotifywait and inotifywatch commands (maintained by Eric Curtin as part of the inotify-tools project) allow using the inotify subsystem from the command line.[1] One major use is in desktop search utilities like Beagle, where its functionality permits reindexing of changed files without scanning the filesystem for changes every few minutes, which would be very inefficient.
inotify replaced an earlier facility, dnotify, which had similar goals. Inotify was merged into the Linux kernel mainline in kernel version 2.6.13, released on August 29, 2005;[2] later kernel versions included further improvements. The required library interfaces were added into the GNU C Library (glibc) in its version 2.4, released in March 2006, while the support for inotify was completed in glibc version 2.5, released in September 2006.[3]