luckyBackup is a powerful, fast, reliable, and fully customizable backup and sync tool. It can backup any directory (the source) to another (the destination). luckyBackup copies over only the changes you've made to the source directory and nothing more, saving a great deal of time for backups after the first one. Whatever changes you make to the source, including adding, moving, deleting, modifying files or directories, will have the same effect on the destination. Owner, group, time stamps, links, and permissions of files are preserved (unless directed otherwise). The synchronization feature works on any pair of directories, keeping the files that were most recently modified on both of them. It includes many safety checks to prevent accidental loss of data.
Easysync allows you to synchronize files among different computers. You pick up a directory you want to synchronize and Easysync will perform synchronisation whenever this directory is changed. The server part propagates the sync signal among clients, so that if there is a change on one client, all other clients will perform synchronization. It is based on Unison.