Add section: Motivation: "Why should I bother to learn the command line?"

You talk at the start about how command-line stuff is more powerful. If you could include one or two more commands that show that, that would make this hugely useful. I'm not sure - maybe searching? ooh - or batch rename (rename –v 's/foo/bar/g' *), that's the kind of that might be useful to people. (though I guess showing people regular expressions could lead to problems...)