Use rsync to synchronize directories/backup

rsync -rtvlz –progress –size-only /home/    /media/usb_disk/home/back_up/


-r copies also all subdirectories within main directory
-t preserves modification times
-v verbose mode, shows more information
-l copies symbolic links
-z compresses files for faster transfer
–progress shows progress during transfer
–size-only compare files based on their size instead of hashes (less CPU, so faster)