[wnd]

#! /bin/sh

while true; do
        cp -dpR source destination
        sleep 2
done

Especially if you only need to do this temporarily, a simple script should suffice just fine. Note that if you're processing large number of files, two second interval could prove to be a bit too short.

If you want to make copying smarter (only copy the files when they're changed), use rsync.

#! /bin/sh

while true; do
        rsync -u source destination
        sleep 2
done

If you want copying to /start/ every N seconds, you could replace the main loop with something like the following. It will /not/ handle fractions of seconds well so it's not very accurate.

n=10 # start copy every N seconds
before=$(date +%s)
while true; do
        # copying happens here
        after=$(date +%s)
        sleep $(( n - after + before ))
        before=after # save one call to date
done

If you're running Windows you can install Cygwin, or rewrite the script as batch-program.