Rsync-Memento

Rsync (Remote Synchronization) is a software for transferring and synchronizing files between two folders. These folders can be on different hosts which permits to have remotes backups. Rsynch is generally used for system backups and synchronizing systems data.
Moreover, it allows to copy data incrementally, i.e. it only copies the bytes that have been added or modified. In addition, it has built-in features such as SSH for secure remote transfer and Zlib for data compression during transfer (in particular for low connections or if you don't want your bandwhidth to be saturated).

All these features make it a very powerful tool compared to the usual commands such as cp, rcp or scp.

A version with graphical interface is available, named Gsync. In addition Timeshift uses rsync behind for copy management.

Use

The basic command is formed as follows :
rsync source-path/ destination-path/

This command can be executed for a remote host. :
rsync source/ login@destination-server:/destination-path

Beware of whether or not to add the slash to the source folder. destination will copy the entire backslash and its contents while destination/ will only copy the contents of the folder.

Main options

Option	Description
-a (--archive)	Combine actually these options : -rlptgoD ==> -r (--recursive), -l (--links), -p (--perms), -t (--times), -g (--group), -o (--owner), -D = --devices --specials. It essentially keep all the data and the metadata
-v (--verbose) or -vv	Verbose mode
-h (--human-readable)	Output numbers in a human-readable format
-z (zlib)	Compress files during the transfer (unnecessary in local transfer)
--progress or --info=progress2 (for total percentage)	Show a progress bar during the transfer
--delete	Delete files in destination that where removed from source
--delete-after	Like --delete but only after the transfer has finished
--ignore-existing	Files already exist in destination are not updated

Useful commands

rsync -ah --info=progress2 --delete /source /dest

SSH :
rsync -azh -e ssh user@IP:/source /dest (or inverse source and dest)

SSH with specific port :
sudo rsync -azh -e 'ssh -p portNumber' user@IP:/source /dest (or inverse source and dest)