simple backup/snapshot system (common files)

 Back In Time is a framework for rsync and cron for the purpose of
 taking snapshots and backups of specified folders. It minimizes disk space use
 by taking a snapshot only if the directory has been changed, and hard links
 for unmodified files if it has. The user can schedule regular backups using
 cron.
 .
 This is the common framework for Back In Time. For a graphical interface,
 install backintime-qt.
 .
 To back up to SSH or encrypted filesystems, install the additional sshfs
 or encfs packages.