Currently rsync doesn't support this feature. This is on the feature request page of some site. Is has an option --fuzzy
-y, --fuzzy This option tells rsync that it should look for a basis file for any destination file that is missing. The current algorithm looks in the same directory as the destination file for either a file that has an identical size and modified-time, or a simi‐ larly-named file. If found, rsync uses the fuzzy basis file to try to speed up the transfer. Note that the use of the --delete option might get rid of any potential fuzzy-match files, so either use --delete-after or specify some filename exclusions if you need to prevent this. freefilesync
Description:
folder comparison and synchronization tool This is a folder comparison and synchronization tool. It is optimized for highest performance and usability without restricted or overloaded UI interfaces.
Features:
* Multiple folder pairs
* Batch capability
* Binary comparison
* Handle conflicts and propagate deletions
* Optimized performance
* Transactional file copy
* ...
Mirror option in freefilesync
There is an award winning cross platform app called freefilesync( http://sourceforge.net/projects/freefilesync/ ) with nice GUI. It has a batch mode will allow you to schedule sync. It's xml file that define left,right folders for sync. Using this feature you can use freefilesync from terminal.
Thus you can sync files and folders using
*GUI
*BASH script
*cron
Do to its superb features and ease of use and script support FreeFileSync can be used as an alternative to rsync