How do I do this?

I have a table with column filepath with contents that look like the following:

filepath
==============
/var/log/foo
/var/log/bar
/var/cache/foo
/var/cache/bar
/var/foo
/var/bar

Is there anyway to retrieve the directory information only regarding those 
filepaths?

So that I can get

/var/log
/var/cache
/var

as the result of a query?

Thanks!

(I am using PostgreSQL 7.4)



Wei