I never said that '%!command' was a bad thing. I was just pointing out that that particular use-case was already built into the editor. We could make pedantic arguments about Unix all day long (e.g. "Each command should do something specific and do it well, Vim doesn't need the :sort built-in" vs "Why should I incur the cost of starting up another process and having it eat up my precious memory space?") but it's relatively useless.

Being able to pipe through commands is a powerful tool, but using an example where the external command already has a built-in equivalent seems possibly confusing to the (novice Vim'er) reader (please don't rattle me off the laundry list of options that /usr/bin/sort has that :sort doesn't because you'd be missing the point).

That said... On the topic of ranges, never give :bd! a range unless you know what you're doing. I ran :bd! once while I had a number of lines selected in visual mode because I though that the selected lines wouldn't affect :bd. Bad idea. The '<,>' part of the range apparently is converted to line numbers (e.g. '3,6') and then :bd reads that range as the buffers to delete. So when you select lines 1-8 and then hit :bd! it goes something like this:

  :<,>bd! -> :1,8bd! -> delete buffers 1-8 without prompting for unsaved changes

Oops!

You're absolutely right (and sort's options are rather quirky), just trying to nudge people to thinking about piping through shell commands that way. There's a lot of power in the ex parts of vi (the : commands) that I seldom hear vi(m) users mention.