qlmanage -p ~/Desktop/MyTowel42.pdfWhile open, click the space bar to go back to your Terminal session. The most notable use case here is that when you use qlmanage you don’t run the risk of changing the date/time stamp of the files.
QuickLook scans file contents before you open those files. Usually this just lets you view a file quickly. But you can also use this same technology from the command line to bring about a change to the Finder without actually opening a file. To access QuickLook from the command line, use qlmanage.