iTunes: Move backup location to an external hard drive

I got a new MacBook Pro with a 256 GB SSD, so not enough storage to back up all of my family’s iOS devices, to say the least. The solution was to back up to an external HDD. Here’s how to do it:

1. With iTunes closed, open the terminal and cd to ~/Library/Application Support/MobileSync/
2. Delete or rename “Backup” folder within (i.e. rm -rf Backup or mv Backup BackupOld)
3. Create the symlink like so:

ln -s /Volumes/<Your External HDD>/MobileSync/Backup ~/Library/Application\ Support/MobileSync/Backup

4. Open iTunes and back up your device
5. Verify that it’s copied to ~/Library/Application\ Support/MobileSync/Backup
6. Enjoy free space on your MacBook