[thelist] Unfamiliar with MAC OS X, how do I see the size of a file

Hi

I have a client who uses Mac OS X, and we're playing with jpeg compression
so I wanted to see the file sizes. She didn't know how to do that, and nor
did I.

So, can anyone tell me how I can view a file directory in OS X? I presume
there's some equivalent of Window's file manager but we couldn't find it.
And if anyone knows how to get at the UNIX underpinnings that would be nice.
I can use basic stuff like ls then.

Cheers
J