rsync confirmation message?

Guys,

I'm using a shell script to backup files, and would like to know if it's possible to take the results of a successful rsync backup (and/or an error message) and use this (possibly using system events?) to produce simple messaging (dialogs)?

This is the first time Ive used shell scripts in AS and I've tried several ways to do it, but none have worked thus far.

this is where I am presently with this part of the script:

try
set src to POSIX path of ("USBDRIVE:" as alias)
set dest to POSIX path of (choose folder with prompt "Choose the destination directory" default location (path to desktop))
display dialog "Your files are being Archived" & return & ". . . . please wait while this process completes" giving up after 3
do shell script "rsync -blah " & quoted form of src & space & quoted form of dest
on error
display dialog "ARCHIVING OF FILES FAILED !!" & return & return & "Please Manually transfer the files from" & return & "the CFCARD to the Backup Drive"
end try

Inserting a simple dialog at the end of this script does not confirm a successful backup, and pops up regardless of what's happened of course.

I doubt this is the best way to do what I've done so far, but as a newbie, I'm still learning!

Thanks