So, there are lots of different versions of Unix out there: HP-UX, AIX, BSD, etc. Linux is considered a Unix clone rather than an implementation of Unix. Are all the "real" Unices actual descendants of the original? If not, what separates Linux from Unix?

Is UNIX an acronym? What does it stand for?

Plan 9 was developed by Bell Labs as a successor to Unix. Although for various reasons it never quite materialized as such, a fair amount of development still went into Plan 9. My question is, what - if anything - from Plan 9 has made its way into modern Unix?

I read in a book written by Robert Love that: > Linux supports the dynamic loading of kernel modules. He said this is the difference between Linux and Unix, but I seem to recall there is also KLD in FreeBSD? So can KLD also be seen as dynamic loading of kernel modules?

What does *uni* mean in **unistd.h** Does it mean unix? or universal? What is it?

What things should any self-professed UNIX expert have under their belt? I'm looking to fill any gaps in my knowledge. Some things I can think of off the bat: - Shell (interactive and scripting) - Common utilities (grep, ls, etc.) - vi (possibly Emacs too) - Some mix of sed / awk / Perl (preferably all) - Knowledge of networking standards - Ability to set up common programs: A mail server, file server and so on Probably forgetting a lot, obvious and not-so-obvious. What else?