Rsync
Posted by maggied on 19 Jul 2007 at 01:37 am | Tagged as: Productivity
*NIX users out there may have heard of rsync. Rsync is somewhat similar to rcp or scp, but is, in my humble and completely unbiased opinion, way better. The “big deal” about rsync is the fact that, unlike other forms of copying, rsync only transfers the differences found between the source and target files and/or directories. This makes it ideal when one needs to backup files, or when one is working with files on more than one computer. The first time you run rsync, it copies all the files to the target location. The next time you run it, though, it just copies the differences. Pretty sweet.
Personally, I use rsync when I’m transferring files between the servers at MGH, and the Mac at the lab. Although I ultimately only edit a file or two, it’s preferable to have the subject’s full folder (about 1GB or so) on the hard drive. Rsync makes this a real piece of cake.
Rsync, like lots of other powerful and useful programs, would be all over the place, if only it were extremely intuitive. I don’t think it is that bad (I just use rsync -a source target), but IBM has a really great article about rsync for those who want a better feel for it than that. The article can be found here.
A related program is Unison. It’s a file synchronizer that essentially does the rsync thing both ways (I think it’s built off the rsync protocol). It attempts to merge files if changes are made on both sides, and raises a conflict when that’s not possible. It will try to synchronize cross-platform and cross-whatever, but it’s not as good at that as the authors claim it is because of issues like case-[in]sensitivity, forbidden characters in file names, etc.
I haven’t used it, but the 6.033 staff seemed to like it for keeping laptops in sync with desktop machines. They did have one complaint that, on a few occasions over the last decade, it managed to delete entire archives because of some kind of inconsistent state. The Unison maintainers claim it’s only happened once to them, but the 6.033 staff insist it happens quite a bit more often.