The Unix System

I dug out my copy of "The Unix System" by SR Bourne the other day for Jan to have a look at while she gets to grips with the shell commands on her new Eee pc. This book was my bible when I first started on Unix systems umpty tum years ago, but I was quite amused to read it again and see that at the time of writing in 1982 there were "more than 3000 Unix systems in use worldwide". At the last count there are nine systems in this house with some variant of Unix on, or ten if you count my bootable flash drive as well ... plus ca change, I suppose.