-a
all (symlinks, etc)
-r
recursive
-n
SIMULATION
-v
verbose
--delete
mirror removed files on dest
--exclude=._*
remove mac hidden files such as "._DSSTORE"
rsync -arnv --delete --exclude=._* "/Path/to/files/source/" "/Path/to/files/dest/"
rsync -arv --delete --exclude=._* "/Path/to/files/source/" "/Path/to/files/dest/"