Rsync to updated backup between folder A and B on CentOS Linux
1. If source is folder A, and destination is folder B, rsync will not produce new folder A in folder B, only backup files under folder A.
> rsync -rulptgo /A/ /B
-r recursive : recurse into directories
-u update : skip files that are newer on the receiver
-l links : copy simlinks as symlinks
-p perms : preserve permission
-t times : preserve modification times
-g group: preserve group
-o owner: preserve owner
-v verbose : increase verbosity
-a stands for -rlptgoD