That’s not really a trick question though it might seem like it. If a sync is in one direction– from source to destination– it’s a one way sync, right? Almost, but not quite.
The basic ways to sync or copy or backup files are easy. Drag and drop. Select a bunch of files in a folder and drag them to a folder on an external disk, or another Mac, and you’re done.
Or, add any one of dozens of backup and sync apps to your Mac, select the source files and folder, select the destination files and folder, and click. Minutes later a folder elsewhere is synced up nicely with the same folder on your Mac.
Or, simply use OneWaySync. The app’s name describes what actually takes place. Almost. Files get synced from a folder on your Mac to a folder somewhere else (on your Mac, on an externally connected disk, etc.). One way. More on that in a moment. OneWaySync’s claim to fame, though, is twofold.
First, it uses the now standard source and destination, left to right, copy and sync.
That means the files in the source folder remain the same, but the files in the second, or destination folder, become exactly the same files as the source folder.
Secondly, OneWaySync is cheap. You’d get change back from a $3-dollar bill. That alone makes it worthy of a try. The app lets you created one way mirrored folder backups from 14 presets. That means it’s easy to backup iPhoto or Photos, or iTunes, or the Documents folder and have them saved to an external disk.
The list of notable caveats is long, though. For example, ‘Delete on Destination’ setting isn’t recommended to be on all the time. And, there are special steps to backup and sync iPhoto or Photos files because both iPhoto and Photos keep all photos in a package instead of a folder.
Still, OneWaySync is fast, easy to setup and use, and just plain doesn’t cost much. There are better solutions which do more, to be sure, but most are priced far more, more complex to use, too.
Now, about the one way of OneWaySync. Indeed, it’s one way, and not really a mirror of files in two folders where if you change, add, or delete a file from either folder, the changes are mirrored.