inotify

inotify?

inotify (inode notify) is a Linux kernel subsystem to notice changes on file system. (quoted from wiki) You can enjoy this functionality via inotify-tools package.

Installation is quite easy (as always).

$ apt-cache search inotify-tools
inotify-tools - command-line programs providing a simple interface to inotify
$ sudo apt-get install inotify-tools
$ inotifywa<TAB>
inotifywait   inotifywatch

You can make use of these tools to watch tagger directory and do some action(s). For example,

#!/usr/bin/env bash

while inotifywait -e create,modify /tmp; do
    echo "Lupin, something happened under /tmp directory"
done

Touching file “hi” under /tmp directory will yield.

$ ./watch.sh
Setting up watches.
Watches established.
/tmp/ CREATE hi
Lupin, something happened under /tmp directory

In the above sample, inotifywait monitors following events:

• CREATE
• MODIFY

You can monitor other events like OPEN/CLOSE/DELETE/ATTRIB. And if you would like to configure inotify* to monitor directory recursively, then you can use -r option for that sake.

Fine.

libnotify-bin

Now we have a method of detection. Next item is means to notify you.

There is a tool called libnotify-bin, which sends message to notification daemon.

$ apt-cache search libnotify-bin
libnotify-bin - sends desktop notifications to a notification daemon (Utilities)
$ apt-get install libnotify-bin

As far as I checked, libnotify-bin has already been installed by default.

Sending a message will give you pop-up message on desktop.

$ for i in `seq 10 -1 0`
> do
> echo $i|festival --tts
> done && notify-send 'Ten Count! Knockout!'

You win!

automatic start upon login

It may not be appropriate to put here though, let’s make use of /etc/profile.d directory for automatic start up upon login.

Prepare a script, which launches inotifywait under the name of, say, watchCore.sh.

#!/usr/bin/env bash

while inotifywait -e create /var/cores; do
    notify-send -u critical "a new core file is created. Please check /var/cores directory"
done

Deploy another script under /etc/profile.d directory which launches former one.

#!/usr/bin/env bash

nohup <PATH>/watchCore.sh 1> /dev/null 2>&1 &

Please do not forget to run script in background. :-)

Voila!