OS X: Running a script when a USB drive is inserted

I rsync all my data to a USB drive that I keep at work. I wanted a way to have my rsync script automatically run when I plugged in the drive – kinda like Time Machine.

It ended up being pretty simple. All I needed to do is create and AppleScript and attach it to a “Folder Action” for the /Volumes folder. This script below is launched when a new item is added to the /Volumes folder, i.e. when you insert a new volume. This script will try to run a BASH script if it exists on that volume (.OnInsert)

on adding folder items to this_folder after receiving these_items
	repeat with current_item in these_items
		try
			do shell script POSIX path of current_item & ".OnInsert"
		end try
	end repeat
end adding folder items to

Save this as a .scpt file and put it in ~/Library/Workflows/Applications/Folder\ Actions folder.
Next, right click the /Volumes folder and select Services -> Folder Action Setup and attach the script you just created
AutoMagic!