Install inotify-tools on Debian based systems:

root@host:~# apt-get install inotify-tools

Watch a file or directory – recursively – for changes until a given timeout is reached of CTRL+Ctrl is pressed. Display a set of statistics on the monitored filesystem objects. In this example the directory /tmp is watched for 60 seconds:

root@host:~# inotifywatch -t 60 -r /tmp
Establishing watches...
Finished establishing watches, now collecting statistics.
total  access  modify  close_write  open  create  delete  filename
159    146     9       1            1     1       1       /tmp/

Use the -z command line option in order to display all rows and columns, even if the counters there are zero.

Watch a file or directory for a specific event. In this example the file /etc/hosts is monitored for an event from the close system call. This event is triggered in a second shell with a simple call of cat /etc/hosts:

root@host:~# inotifywait -e close /etc/hosts
Setting up watches.
Watches established.
/etc/hosts CLOSE_NOWRITE,CLOSE

root@host:~# echo $?
0

Obviously the inotifywait command is best suited for the use within (shell) scripts in order to trigger a specific behaviour upon the occurance of a certain set of filesystem events.

Linux Magazine - Issue 194 - Core Technology - Filesystem monitoring