incron
incron is an "inotify cron" system. It consists of a daemon and a table manipulator. You can use it a similar way as the regular cron. The difference is that the inotify cron handles filesystem events rather than time periods.
Installation
Activation and autostart
After installation, the daemon will not be enabled by default. You can enable incrond.service.
Configuration
Incrontabs should never be edited directly; instead, users should use the incrontab program to work with their incrontabs.
Using incrontab
To view their incrontabs, users should issue the command:
$ incrontab -l
To edit their incrontabs, they should use:
$ incrontab -e
To remove their incrontabs, they may use:
$ incrontab -r
To reload incrond, use:
$ incrontab -d
To edit another user's incrontab, isue the following command:
# incrontab -u user -e
Incrontab format
Each row in an incrontab file is a table that the dameon runs when an event happens to a certain directory or file.
The basic format for an incrontab is:
path mask command
- path
- the directory or file that incrond will monitor for changes.
- mask
- the type of filesystem event that incrond will monitor for. This paramter can be seperated by commas.
- command
- the command to be run after the specified filesystem event(s) occur.
Mask types
incrontab uses mask types to specify which file system event to monitor for. For more options see inotify(7)
To trigger a command if a file is accessed or read:
IN_ACCESS
To trigger a command if metadata of a file change (e.g. timestamps, permissons):
IN_ATTRIB
To trigger a command if a file opened for writing is closed:
IN_CLOSE_WRITE
To trigger a command if a file or directory not opened for writing is closed:
IN_CLOSE_NOWRITE
To trigger a command if a file or directory is created in a watched directory:
IN_CREATE
To trigger a command if a file or directory is deleted from a watched directory:
IN_DELETE
To trigger a command if a watched file or directory is deleted (or moved to a different filesystem):
IN_DELETE_SELF
To trigger a command if a file was modified:
IN_MODIFY
To trigger a command if a watched file or directory is moved within the filesystem:
IN_MOVE_SELF
To trigger a command if a file or directory is moved out of the watched directory:
IN_MOVED_FROM
To trigger a command if a file or directory is moved to the watched directory:
IN_MOVED_TO
To trigger a command if a watched file or directory is opened:
IN_OPEN
Custom Mask Types
Incrond provides additional custom event types to modify its monitoring behavior.
For instance, to pause monitoring an event until the current one is completely handled, add loopable=true to the event list, eg:
IN_CLOSE,loopable=true
An event with the loopable event enabled will not fire again until the associated command exits.
See incrontab(5) for the complete list of custom mask types.