There are lots of fancy programs for Linux to find out where your gigabytes are sitting and filling your hard drive, the simplest of them is
du (from disk usage). The trick is to use the
--max-depth=1 option so that you get a view of which folder weighs how much. Try this:
peterbe@trillian:~/tmp $ du -h --max-depth=1
Pretty nifty! That way you can quickly see which folder contains the most junk so that you can free up some hard drive space.
To sort it I don't know how to reformat it into human readable values but there's the command:
peterbe@trillian:~/tmp $ du --max-depth=1 | sort -n