Minecraft wiki entry for Mac_Scripting_Tutorial, associated text: Rsync is a powerful file transfer tool with many uses, but the one we care about most here is its ability to look at a whole bunch of files at a source and at a destination, and then only transfer the files from source to destination that are different. Tectonicus generates lots and lots and lots of files, and you will save huge amounts of time by transferring to your web server only the new bits of the map every night instead of copying the whole thing every time.