BASH - Directories - Monitor a directory for changes - Using incron

incron is like cron but instead of time-based events, the events are based on file notifications.

Install incron

sudo apt install incron

Add users to the /etc/incron.allow file who are allowed to use incron.

peter

NOTE: One user per line.

/etc/incron.deny can also be used to specifically prevent usage of incron by a user.

Edit the incron table:

incrontab -e

and populate with:

/etc/apache2/apache2.conf IN_MODIFY /usr/sbin/service apache2 stop

/home/peter/some_dir_to_watch IN_MODIFY echo "$$ $@ $# $% $&"

NOTE: This monitors the directory for changes and will perform the echo passing along some parameters.

The format is very picky; use spaces, not tabs!

Parameters can include:

Events to monitor include:

IN_ACCESS: If a file is accessed or read.
IN_ATTRIB: If metadata of a file change (e.g. timestamps, permissions).
IN_CLOSE_WRITE: If a file opened for writing is closed.
IN_CLOSE_NOWRITE: If a file or directory not opened for writing is closed.
IN_CREATE: If a file or directory is created in a watched directory.
IN_DELETE: If a file or directory is deleted from a watched directory.
IN_DELETE_SELF: If a watched file or directory is deleted (or moved to a different filesystem).
IN_MODIFY: If a file was modified.
IN_MOVE_SELF: If a watched file or directory is moved within the filesystem.
IN_MOVED_FROM: If a file or directory is moved out of the watched directory.
IN_MOVED_TO: A file or directory is moved to the watched directory.
IN_OPEN: A watched file or directory is opened.

IMPORTANT: incron is not capable of watching sub-directories.

Only files within the path will be monitored.

If sub-directories need to be monitored, they must be given their own entry.

incrontab -l