linux - How to continuously monitor the directory using dnotify /inotify command

Question

I am new to dnotify/inotify command. Can any one help me how to write a script such that it continuously monitors a directory and indicates that there is some change or modification to it.

Answer 1

Inotify itself is a kernel module accesible via calls from e.g. a C program. http://www.ibm.com/developerworks/linux/library/l-ubuntu-inotify/

There is an application suite called inotify-tools, which contains:

inotifywait - wait for changes to files using inotify

http://linux.die.net/man/1/inotifywait

and

inotifywatch - gather filesystem access statistics using inotify

http://linux.die.net/man/1/inotifywatch

You can use inotify directly from command line, e.g. like this to continuously monitor for all changes under home directory (may generate lots of output):

inotifywait -r -m $HOME

And here is a script that monitors continuously and reacts to Apache log activity, copied from the man file of inotifywait:

#!/bin/sh
while inotifywait -e modify /var/log/messages; do
  if tail -n1 /var/log/messages | grep httpd; then
    kdialog --msgbox "Apache needs love!"
  fi
done