The terminal command used to sync folders/files between 2 locations, very useful when you want to migrate or backup NAS storage.

rsync -a --progress SourceFolder/Foldername/ DestinationFolder/Foldername/

-a = create an archive including the original owner and timestamp.
–progress = show the progress, this will take a bit longer because the system will calculate the total files before starting the synchronization.
ending “/” = the content of the folder exclude the folder itself.