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inotify cron system

(c) Lukas Jelinek, 2006

1. About
2. Requirements
3. How to use
4. Bugs, suggestions
5. Licensing
6. Documentation


========================================================================


1. About
This program is the "inotify cron" system. It consist 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.

2. Requirements
* Linux kernel 2.6.13 or later (with inotify compiled in)
* inotify headers (inotify.h, sometimes inotify-syscalls.h) installed in
  <INCLUDE_DIR>/sys. The most common place is /usr/include/sys.
* GCC 4.x compiler (probably works also with GCC 3.4, possibly with
  older versions too)

  
3. How to build
Because this version is very early it does not contain a standard
portable build mechanism. There is only a Makefile which must be
modified manually. On many Linux systems you need not to change
anything.

Please review the Makefile BEFORE you type 'make'. Especially
check the PREFIX and other common variables. If done you can
now build the files ('make').

The binaries must be of course installed as root. Note that the
installer creates a special user called 'incron' which manages
the incron tables.


4. How to use
The incron daemon (incrond) must be run under root (typically from
runlevel script etc.). It loads the current user tables and hooks
them for later changes.

The incron table manipulator may be run under any regular user
since it SUIDs. For manipulation with the tables use basically
the same syntax as for the crontab program. You can import a table,
remove and edit the current table.

The user table rows have the following syntax:
 <path> <mask> <command>

Where:

  <path> is a filesystem path (currently avoid whitespaces!)
  <mask> is a symbolic (see inotify.h; use commas for separating
         symbols) or numeric mask for events
  <command> is an application or script to run on the events

The command may contain these wildcards:

  $$ - a dollar sign
  $@ - the watched filesystem path (see above)
  $# - the event-related file name
  $% - the event flags (textually)
  $& - the event flags (numerically)

The mask may additionaly contain a special symbol IN_NO_LOOP which
disables events occurred during the event handling (to avoid loops).

Example 1: You need to run program 'abc' with the full file path as
an argument every time a file is changed in /var/mail. One of
the solutions follows:

/var/mail IN_CLOSE_WRITE abc $@/$#

Example 2: You need to run program 'efg' with the full file path as
the first argument and the numeric event flags as the second one.
It have to monitor all events on files in /tmp. Here is it:

/tmp IN_ALL_EVENTS efg $@/$# $&


5. Bugs, suggestions
THIS PROGRAM IS AN ALPHA VERSION. IT PROBABLY CONTAINS BUGS AND
THEREFORE IT IS NOT INTENDED FOR PRODUCTION USE.

If you find a bug or have a suggestion how to improve the program,
please use the bug tracking system at http://bts.aiken.cz.


6. Licensing
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License,
version 2  (see LICENSE-GPL).

Some parts may be also licensed covere by other licenses.
Please look into the source files for detailed information.