Simple synchronising and back up of two folders for Linux

To simply synchronise / back up two folders I use rsync.
I have several folders on two different networked devices (NAS's) I want to keep in sync.
I use a script to this. I could automate this but I like to see the magic happen. Maybe I'll automate this later with a cron job but for now:
I log into one of the NASs using SSH.
Note: I have setup public and private certificates so I don't need to enter passwords. I'll leave that as an exercise for the user.

$ ssh aUser@192.168.0.3

then I run my script on that box:

remotebox:~# sh syncFiles.sh

The contents of this script is as follows:
rsync -avP --delete aUser@192.168.0.4:Shares/Public/movies/ /mnt/HD/HD_a2/movies/
rsync -avP --delete aUser@192.168.0.4:Shares/Public/music/ /mnt/HD/HD_a2/music/
rsync -avP --delete aUser@192.168.0.4:Shares/Public/pictures/ /mnt/HD/HD_a2/pictures/

As you can see from above I backup movies, pictures and music from 3 folders.

The syntax is as follows:
rsync <parameters> <source> <destination>

The parameters are:
 -a means "all" files/folders,

-v means "verbose" so we can see what is happening,
-P means show a progress bar,
--delete means if something is deleted from the source, delete it from the destination. This is great for synchronisation but maybe not what you want for your backup? Use with caution. If in doubt, don't use it initially.
<source> of course is what to copy and
<destination> is where to put it.