How to monitor a complete directory tree for changes in Linux?

Question

How can I monitor a whole directory tree for changes in Linux (ext3 file system)?

Currently the directory contains about half a million files

Answer 1

Use inotifywait from inotify-tools:

sudo apt install inotify-tools

Now create a script myscript.sh that includes hidden files and folders too:

#!/bin/bash
while true; do

inotifywait -e modify,create,delete,move -r $1

done

Make the script executable with chmod +x myscript.sh

Run it with ./myscript.sh /folder/to/monitor

If you don't provide argument it will use the working directory by default.

Also, you can run several commands adding && \ at the end of the previous command to add the next one:

#!/bin/bash
while true; do

inotifywait -e modify,create,delete,move -r $1 && \
echo "event" && \
echo "event 2"

done

If you don't want to execute any command on events, just run the command directly with the -m modifier so doesn't close:

inotifywait -e modify,create,delete,move -m -r /path/to/your/dir

Answer 2

I've done something similar using the inotifywait tool:

#!/bin/bash
while true; do

inotifywait -e modify,create,delete -r /path/to/your/dir && \
<some command to execute when a file event is recorded>

done

This will setup recursive directory watches on the entire tree and allow you to execute a command when something changes. If you just want to view the changes, you can add the -m flag to put it into monitor mode.