Its old and from a crappy source but...
Like the title says, its very old, made the year i was born in fact, but it still provides good quick information while scanning it. I'm sure some of you have seen this throughout the years, but i found it while searching for unix security texts. It was written by a lame dude, who is loved by hackers im sure. but still its a good link, its free, print it off and use it for reference.
http://www.undergroundnews.com/files...ng/unix001.htm
p.s. its not about hacking, its a guide to the fundamentals of unix and some common security stuff. its just that some lamers find stuff like this and call it hacking just because they are reading about Unix. but meh, like i said its a good text, have fun.