If you have a laptop and a desktop computer (or just two machines of any type), you may have run into a problem where you have the same files or directories on both machines. You start editing, and want to make sure you have the most current version on both machines.
There are several good software solutions for keeping multiple machines and directories in sync, but the one I like to use is called ChronoSync. I bought this program several years ago when I first got a Mac laptop and a desktop and wanted to keep some of the directories in sync. It was great software then, and it just keeps getting better.
ChronoSync will let you sync up files and directories on local hard drives or across a network. Because you don't need anything special on the other computer, you can sync up to Windows machines, Linux boxes, BSD systems – if you can mount it, you can sync with it. (An "Agent" is available, for $10, that you can put on other Macs to get some extra features, like special permissions, but I''ve never used it.) This is great for me at work, as I have my company-issued Windows desktop and my own MacBook Pro laptop that I bring with me. With ChronoSync, I can sync up the "My Documents" folder and a few other key folders from my desktop and have them with me in meetings. You can set up an auto schedule, and ChronoSync can be set to automatically mount and dismount any necessary network drives. I have mine set to copy my work documents Mon-Fri at 50 minutes after the hour between 8 AM and 4 PM, and it's set to send me an email if something fails (a file can't be copied, a drive can't be mounted, etc.).
I can also sync up files I use for my side work, web site and proofreading, between my desktop and my laptop, so I always have the most current version available.
(Click on the graphic to see it larger.)
This is a "Sync Document" that I use to keep my Real Basic computer program source code in sync between the two machines. You can have as many of these as you want, and either start them manually or via the built-in scheduler. There's a lot of options just on this page, not to mention some found on other tabs, such as filtering (I leave off Access database files and temporary files from my work cloning). You can set things up to keep both directories in sync, or just always push one side to the other (which is really a backup at that point, such as when I copy my iBank documents off to my server – the ones on the desktop will always be the new ones unless I am doing a restore, so I set the document to "Left-to-right" instead of "Bidirectional"). You can set it to delete files on one side if they are deleted on the other (or to archive those deletions first, throwing them in an archive directory). You can also do a "Trial Sync" which will just tell you want files would be copied and/or archived.
ChronoSync can evan make a bootable backup for you if you want. I haven't tried this feature since I use SuperDuper!, but you could certainly use it for that too.
Econ Technologies, the authors of ChronoSync, have a great policy for upgrades as well – they're FREE for life. I bought ChronoSync back as version 1 or 2 – they're up to version 4.1, and it's still free. They've added a lot of features along the way, such as the bootable backups) and have never asked for another dime. For $40, it's well worth having if you need to keep any directories in sync between two machines, or just want to use it for backing up. I've barely scratched the surface of what ChronoSync is capable of – have a look for yourself at the Econ web site.