Thank you Loops and 7stud for your explanations. You have certainly given me a few things to chew over and experiment with.
in reply to [SOLVED] Pack/unpack - understanding the '@' and '.' templactes
Whoever wrote the pack tutorial and pack docs should be shot. I vote for deleting the current pack tutorial and pack docs, and starting with what Loops wrote.
I doubleplus agree with that (the deleting the existing docs part, not the shooting bit). The existing pack and packtut pages desperately need a vigorous round of editing - preferably with a gang mower and a fire axe. The previous author should be sentenced to rewriting the GNU tar man/info pages until they are clear enough to actually use.