File and directory names can contain spaces and require special treatment. This should be addressed up front, before introducing commands with side effects.
How about including some examples of globbing all files of a given type including filenames with spaces?
e.g. 1) Find all file names in a directory that contain spaces and replace spaces with _
2) E.G save mp3 format sound out of a directory full of flv files using ffmpeg, flv files can have arbitrary file names, mp3 file names saved with no spaces
That kind of activity would be interesting to younger proto-hackers
I'm a teacher. A group of teenagers in a computer room (which is not your target audience) would not actually read your tutorial in an a to b fashion, but, when set a task would raid your work for the bits that help then achieve the task. I'd then follow up with a multi-choice quiz in Moodle or something similar to structure recall like your flashcards.
