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--- directory:run_a_command_upon_files_or_directories_changes [2021/01/26 10:14] – [Test inotifywait] peter
+++ directory:run_a_command_upon_files_or_directories_changes [2021/01/26 10:53] (current) – removed peter
@@ Line 1: / Line 1: @@
-====== Directory - Run a Command Upon Files or Directories Changes ======
-Use either inotifywait or iwatch.
-----
-===== Using inotifywait =====
-==== Install inotify-tools ====
-<code bash>
-sudo apt install inotify-tools
-</code>
-----
-==== Test inotifywait ====
-In a shell enter:
-<code bash>
-while true; do
-  res=`inotifywait -r thedirtowatch/ --format %f`;
-  echo "RESULT=$res";
-done
-</code>
-returns:
-<code>
-Setting up watches.  Beware: since -r was given, this may take a while!
-Watches established.
-</code>
-<WRAP info>
-**NOTE:**  The **<nowiki>--format %f</nowiki>** refers to the filename in the event.
-  * **<nowiki>-r, --recursive</nowiki>**:  Watch all sub-directories of any directories passed as arguments.   Watches will be set up recursively to an unlimited depth.
-    * Symbolic links are not traversed.  Newly created sub-directories will also be watched.
-See http://manpages.ubuntu.com/manpages/focal/man1/inotifywait.1.html for options.
-</WRAP>
-----
-In a 2nd shell, go to that directory being watched.
-<code bash>
-cd thedirtowatch/
-touch test1
-</code>
-<WRAP info>
-**NOTE:**  Back on the 1st shell this should show you output:
-<code bash>
-RESULT=test1
-</code>
-</WRAP>
-----
-===== Only listen for certain events =====
-Change the inotifywait to the following:
-<code bash>
-while true; do
-  res=`inotifywait -q -e create, open, close, modify, moved_to, moved_from -r thedirtowatch/ --format '%e %f'`;
-  echo "RESULT=$res\n";
-done
-</code>
-<WRAP info>
-**NOTE:**  The additional **-e** option can be added to the inotifywait to only listen for certain events.
-Events include:
-  * **access**: A watched file or a file within a watched directory was read from.
-  * **modify**: A watched file or a file within a watched directory was written to.
-  * **attrib**: The  metadata  of a watched file or a file within a watched directory was modified.
-    * This includes timestamps, file permissions, extended attributes etc.
-  * **close_write**: A watched file or a file within a watched directory was closed, after being opened in writeable mode.
-    * This does not necessarily imply the file was written to.
-  * **close_nowrite**:  A watched file or a file within a watched directory was closed, after being opened in read-only mode.
-  * **close**:  A watched file or a file within a watched directory was closed, regardless of how it was opened.
-    * Note that this is actually implemented simply by listening for both **close_write** and **close_nowrite**, hence all close events received will be output as one of these, not **CLOSE**.
-  * **open**:  A watched file or a file within a watched directory was opened.
-  * **moved_to**:  A  file or directory was moved into a watched directory.
-    * This event occurs even if the file is simply moved from and to the same directory.
-  * **moved_from**:  A file or directory was moved from a watched directory.
-    * This event occurs even if the file is simply moved from and to the same directory.
-  * **move**:  A file or directory was moved from or to a watched directory.
-    * Note that this is actually implemented simply by listening for both **moved_to** and **moved_from**, hence all **close** events received will be output as one or both of these, not **MOVE**.
-  * **move_self**:  A watched  file or directory was moved.
-    * After this event, the file or directory is no longer being watched.
-  * **create**:  A file or directory was created within a watched directory.
-  * **delete**:  A file or directory within a watched directory was deleted.
-  * **delete_self**:  A watched file or directory was deleted.
-    * After this event the file or directory is no longer being watched.
-    * Note that this event can occur even if it is not explicitly being listened for.
-  * **unmount**:  The filesystem on which a watched file or directory resides was  unmounted.
-    * After this event the file or directory is no longer being watched.
-    * Note that this event can occur even if it is not explicitly being listened to.
-The **<nowiki>--format</nowiki>** option is changed to include showing **%e** which is the actual event.  Obviously change as needed.
-The **-q** option is to not show too much output.
-See http://manpages.ubuntu.com/manpages/focal/man1/inotifywait.1.html for options.
-</WRAP>
-----
-===== Using a BASH Script =====
-<file bash after-change.sh>
-#!/bin/bash
-#
-# Monitor the input directory and if any change occurs run the provided command:
-#
-# Usage:
-#   after-change.sh /tmp ls -al %f
-if [ $# -lt 3 ]; then
-  echo "Usage: $0 dir cmd "
-  exit 1
-fi
-which inotifywait 2>&1 >/dev/null
-if [ "$?" == "1" ]; then
-  echo "ERROR:  inotifywait not installed."
-  exit 1
-fi
-dir=$1
-shift
-cmd=$1
-shift
-options=$*
-inotifywait -q -r -m $dir $options
-eval $cmd
-</file>
-----
-===== References =====
-http://manpages.ubuntu.com/manpages/focal/man1/inotifywait.1.html