Folder Actions automatically run scripts when files are added, removed, or modified in specific folders on macOS.

How to set up:

1. Right-click a folder in Finder
2. Select Services > Folder Actions Setup
3. Enable folder actions for that folder
4. Attach a script (AppleScript or shell script) to run on folder events

Common automation examples:

• Auto-organize downloads: Sort files into subfolders by type (PDFs to Documents, images to Pictures)
• Image processing: Automatically resize or compress images when added to a folder
• File conversion: Convert documents to different formats
• Backup automation: Copy files to a backup location when modified
• Notification system: Alert you when specific files appear

Example AppleScript:

on adding folder items to this_folder after receiving added_items
    repeat with this_item in added_items
        -- Process each added file
        tell application "Finder"
            -- Do something with this_item
        end tell
    end repeat
end adding folder items to

Use cases:

• Watch a “Screenshots” folder and auto-upload to cloud storage
• Monitor downloads for specific file types and move them automatically
• Process scanned documents as they’re saved
• Auto-rename files based on patterns

Built into macOS, no third-party tools needed.

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