macOS execute command upon directory change via launchd.

README.md

macOS execute command upon directory change via launchd

Using launchd to watch a filesystem directory and upon create/change to a file with the directory, execute a command.

Install

For this example:

• Watching directory of: /path/to/watch.
• Upon file change, execute: /path/to/command argument1 argument2.

Copy, or symlink example.plist under the directory $HOME/Library/LaunchAgents:

$ ln -fs "./example.plist "$HOME/Library/LaunchAgents"

Load example.plist into launchd:

launchctl load "$HOME/Library/LaunchAgents/example.plist"

The example.plist can be removed by running:

launchctl unload "$HOME/Library/LaunchAgents/example.plist"

then deleting example.plist.

Related

• https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/CreatingLaunchdJobs.html
• https://mayeu.me/post/how-to-trigger-any-action-when-a-file-or-folder-changes-on-macos-on-the-cheap/
• https://apple.stackexchange.com/questions/40705/monitor-a-folder-for-changes-and-run-a-command-when-a-change-is-detected/40727#40727

example.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>Label</key>
	<string>example.watcher</string>
	<key>ProgramArguments</key>
	<array>
		<string>/path/to/command</string>
    <string>argument1</string>
    <string>argument2</string>
	</array>
	<key>WatchPaths</key>
	<array>
		<string>/path/to/watch</string>
	</array>
</dict>
</plist>