I've been using Linux for about seven years now, somehow without ever really knowing what I was doing. I use Linux because I like to tinker with my operating system. I can install and remove software from the command line, edit configuration files, change file permissions, create aliases, that sort of thing. And I understand the general theory behind networking, enough to troubleshoot basic connectivity problems on my own. But I never really got much further than that. I bought a couple books and...