Duplicati - Free backup software to store backups online with strong encryption. Works with FTP, SSH, WebDAV, OneDrive, Amazon S3, Google Drive and many others.

Examdiff Pro - It is a simple yet powerful tool that is being used by the professional programmer and developers for the purpose of visual comparison.

snaprd - Snaprd is a program that helps you to make snapshot backups using rsync.

Qtd Sync - A graphical interface for the Rsync engine that will synchronise files between two computers either...

rsync - rsync is a file transfer program for Unix systems. rsync uses the "rsync algorithm" which provides a very fast method for bringing remote files into sync.

Time Machine - Time Machine is the breakthrough automatic backup that’s built right into Mac OS X.