Get used space of startup disk

Hello,

I am working on a script that will detect how much space is used on the startup disk. If it is less than (user-defined) GB, the script will create a giant sparse bundle to make “spaceUsed” equal (user-defined) GB. I am not having trouble making the rest of the script, but I can’t seem to figure out how to figure out the space used.

You need to search the forums… see this
http://macscripter.net/viewtopic.php?id=27074