How can I sync my iTunes music library between two Macs for free?

I have a desktop system that I use as a server. I also have a MacBook Pro that is my main computer. I've done a lot of organization and cleanup of my music library and have it all on my MacBook Pro.

I'd like to be able to keep the music library on my MacBook Pro in sync with the desktop machine so that my wife can access everything from her own MacBook Pro.

I thought about setting up folder actions that would copy the files into the "Automatically add to iTunes" folder. However, since I like to use the "keep my iTunes library organized" option, the files get moved into the iTunes music directory and I can't write a script that will compare my MacBook Pro's iTunes music library with the "Automatic" directory on the server.

Also, a simple file copy will not sync metadata like ratings and plays. Is there a free, automated solution for syncing iTunes libraries between 2 Macs?

Below is how I finally did it based on the rsync suggestion:

I used the link provided by James in this answer (but I took out the --size-only option after the first sync):

iTunes Utility - Merging Libraries

I also took out the --force option (because it's redundant when also using --delete). so my rsync command looks like this:

rsync -av --delete ~/Music/iTunes/ /Volumes/robert/Music/iTunes > ~/Automation/automator/logs/itunes_rsync.log

I then integrated this into an Automator workflow. Looks like this: Get Specified Servers ► Connect to Servers ► Run Shell Script ► Eject Disk.

Creating it as an iCal Workflow is screwy for me because I use MobileMe and the iCal event gets synced with my other machines where I don't want this workflow to run. So instead, I created an agent using Lingon that runs the workflow every 8 hours.

Solution 1:

It's possible to keep libraries in sync using rsync. Google for iTunes and rsync and you'll find some solutions.

Solution 2:

How large is your library? Dropbox has helped many people in this situation, and it will work from anywhere.

UPDATE

Do you use only one computer at a time? Are you the only user of iTunes in each computer? Is your desktop a Mac with the same version of iTunes?

If so, observe this scenario:

You backup your desktop's ~/Music/iTunes folder and then delete it. You then copy the entire ~/Music/iTunes folder from the Macbook Pro to the desktop.

You have your laptop out of the house. You rip a new CD or download some tracks from iTunes or Amazon.com, etc. (but put a copy of the new song files aside in another folder temporarily), then listen, rate songs, etc. all day. Then when you get home, you copy the new files to the Automatically Add to iTunes folder on the desktop and iTunes does its magic of organizing the music files (just like on your Macbook Pro!) Then you replace everything inside the ~/Music/iTunes folder on your desktop with what's on your Macbook Pro EXCEPT the ~/Music/iTunes/iTunes Media folder (where the actual songs reside).

Voilà!

Solution 3:

I have not tried this, but would like to some time: Mashduo. I found this via the excellent One Thing Well website: "A utility for OS X that lets you compare two iTunes libraries, generating a report of songs that don’t appear in both libraries and (optionally) making a zip archive of the missing tracks."

Sounds like some manual work, but may be another approach to achieve what you need.