Sometimes you need to Quick Look a file, but you're in Terminal or iTerm or something. If you're dealing with images, you want to see them before you do anything. But you don't want to use the open command. That's where qlmanage comes in.
qlmanage is a CLI tool that, from the manpage, is a 'Quick Look Server debug and management tool.' It's got more options than described below, but those are for developers debugging QL.
The -p option generates a preview, as if you'd tapped the Space bar in the Finder. The -t option generates thumbnails, like in Coverflow or Info For. Here, then, are typical uses of the tool:
Mac OS X Hints
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