synchronizing your file - tools

http://www.cerebralmastication.com/2011/04/fast-two-way-sync-in-ubuntu/

http://www.cerebralmastication.com/2011/04/details-of-two-way-sync-between-two-ubuntu-machines/

http://www.decisionsciencenews.com/2011/11/19/keep-your-files-in-sync-for-free/