====== Filesystem Monitoring ======

===== Tools =====

Install //inotify-tools// on Debian based systems:

<cli prompt='# '>
root@host:~# apt-get install inotify-tools
</cli>

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

<cli prompt='# '>
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/
</cli>

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'':

<cli prompt='# '>
root@host:~# inotifywait -e close /etc/hosts
Setting up watches.
Watches established.
/etc/hosts CLOSE_NOWRITE,CLOSE

root@host:~# echo $?
0
</cli>

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.

===== Links =====

[[http://www.linux-magazine.com/Issues/2017/194/Core-Technologies|Linux Magazine - Issue 194 - Core Technology - Filesystem monitoring]]\\