Man pages
The most comprehensive source of Unix information is, of course, the Unix man pages. Finding these pages online isn't difficult. Versions exist at the National Technical University of Athens (Greece, not Georgia), Linux Hong Kong, Linux Journal, and SolarisGuide.com. A hypertext version is available at http://www.freebsd.org/.

My first reaction to online man pages was: why? I can always type:

man doodah 

and get the needed reference for the doodah command.

But there are two good reasons to use the online pages. First, the hypertext versions of man pages are very convenient. It's very easy to hop from one entry to the next with a click.

The second reason is even more important: having data available when you need it. I'm currently working for a very large corporation that has several Unix boxes. None of those boxes have the man pages loaded. I've inquired about that several times and cannot find anyone with an answer. The system administrators reply that they've never had man pages and don't know who to ask to get approval to add them.

I'm expected to develop several shell scripts and C++ programs on those boxes, and I've learned to bless the availability of the online man pages, although they're not the friendliest approach to Unix. They're notorious for being the product of cryptic geekdom at its worst. Aside from being obnoxious, they rarely provide examples. Or they provide examples that are completely useless.

I remember once trying to learn a Unix tool called yacc. Without getting too technical, yacc is a specialized language generator that lets you specify the a programming language's grammar using a set of grammar symbols. Yacc is itself a language of sorts, intended as a tool to help a developer create a compiler for new or existing languages.

The yacc utility is very tough to understand and, as I waded through the man page, I began to feel that I desperately needed to see some examples of the yacc language at work.

The man page writer did provide an example. He provided a complete and lengthy listing of the yacc grammar specification for the language itself. At that point, my geek alarm went off. I threw up my hands and went out and bought the dragon book on compiler construction, in which yacc was very nicely explained.

How-to documents
The second important source of information on Unix is how-to information. Anything that makes sense of the man pages and actually discusses examples of using the Unix commands has my blessing. How-tos are also very good at putting several commands together and explaining how to use them. For example, probably one or two dozen commands are used to set up and control a network. If you read all of the man pages entries for those commands, you still wouldn't know how to set up a network. But a how-to can explain it.

How-to documents vary enormously, but you can find several just by searching for Unix and how-to (or howto). I've listed some of the more interesting ones in the resources below.

FAQs
FAQ documents are collections of frequently asked questions, usually compiled by a user group or vendor who's interested in providing answers to user questions. FAQ listings originally came about as a defense mechanism: computer literati were often inundated with questions, many of which were repeated. The members of the user group in question would collaborate on a FAQ listing, then inform those who want a question answered that they must first review the FAQ document.

FAQ listings are so useful that they themselves have been collected into Internet sites such as http://www.faqs.org/faqs/, which offers links to other FAQ documents, including the Usenet FAQ listings. Among these, of course, are the Unix FAQ documents and FAQ listings broken up by Usenet groups such as comp.unix.bsd, comp.unix.misc, comp.unix.shell, and comp.unix.solaris.

FAQ entries tend to be shorter than a how-to or a man page and include everything from the useful (How do I remove a file with punctuation characters in its name?) to the arcane (What does awk stand for?).

Other good FAQ entries are available at the Amsterdam Science and Technology Center, FreeBSD, and OpenBSD; they are listed at the end of this article.

Those listings only scratch the surface of various Unix resources, but they are a rounded collection of sites for looking things up. I use them in search of a new understanding of Unix, and I hope you will, too.