What is PsyncX?
PsyncX is nothing but a wrapper for psync. What that means is that PsyncX uses an existing free Unix application written by Dan Kogai, psync. Hence the name PsyncX (yes, I know it isn’t very original, but I thought it would be fairly easy to understand the connection 🙂
Okay then, what is psync?
Well, the easiest way to find out is to read the man page (Unix speak for manual) for psync:
But seeing as you are trying to figure out whether to install this or not, here is the gist of the man page:
psync does an update copy. It compares source directory and target directory at first, then erases items that are nonexistent on source directory if specified and finally copies everything on source directory. Items with the same modification date and (data fork) size remain untouched, saving time on operation.
What this means is that psync will do an entire copy of whatever you specify the first time. From then on, if you specify the same source directory and same target directory, it will only backup the files that have changed. Finally, unalike most Unix applications, psync will keep all resource forks and other Mac specific attributes for files (if you don’t know what this means, don’t worry about it, it is a GOOD thing 🙂
I’m giving this a try right now and it seems pretty good so far.