My situation is sort of a unique one. To help pay for college, my dad forced me into a summer job doing basic data entry and some light engineering work at a company which did outsourcing for aerospace companies. They had dozens of AIX 4.3 workstations running NFS, NIS, and all of the arcane bullshit everyone used back then.

When the one-woman IT department heard I'd switched majors that spring to CS, she let me take on some of the workload. This mostly consisted of wrangling their VAXstations, handling various requests from users (which I normally passed on to the helpdesk of the company we did most of our work for), and fixing print queues. Eventually, I ended up working on the AIX stuff, too, and then installing and configuring our own servers (AIX and FreeBSD.)

When a branch office closed, I also inherited a Sparc 5 attached to a plotter and a couple of SGI Indigos. (I basically kept the SGIs on my desk because they were useless to our engineers.)

By the end of the summer, I knew more than most 19 year olds should know about AIX, Solaris 2.3, and IRIX 6.2. I stayed there through school during off-semesters and gradually became the go-to person for Unix issues, serving as a mediator between our engineers and the client.

Within a few years of graduation, after the obligatory gig at the failing startup, I ended up as a junior, then senior Unix SA at the aerospace client. It was pretty much the most perfect set of circumstances that could happen, and it was almost as if I had no control over it.

So I guess, for me, being a sysadmin sorta just happened.

That probably wasn't too helpful as a career guide.

As far as the day-to-day side of things goes, though, the only real tools I use these days are google, man pages, and our vendor support, pretty much in that order. And some Hitachi course manuals.

Real SA intuition only comes from experience. Having a degree in CS might seem like overkill, and certainly isn't necessary, but it really doesn't hurt, either. Having a solid fundamental understanding of how computers work at the very lowest level is a huge advantage in the kind of "forensic" work (for lack of a better term) you'll find yourself doing from time to time as an admin.

As far as learning the OS itself goes, and gaining some proficiency at it, my advice is to build, and break, your own systems as often as you can. I basically went through my entire adult life until recently with some sort of Sun, IBM, or SGI machine (usually two or three at the same time) kicking around somewhere in the house: I used them for storage; I learned how to mirror disks; I did tape backups with them; I fucked around with NIS maps and sendmail configurations and DNS. I broke everything dozens of times long before I ever touched an important system at work.

BTW, it took about four years of full time work before I really felt like I knew what the hell I was doing most of the time.

misc: Sites I read every day: HN, reddit, yankees websites, drudgereport (for the lulz.) I really don't keep up with the very latest in tech news or what Oracle or IBM are releasing, unless their sales reps are telling me about it over lunch. There's no need to keep super-current on hardware unless I'm designing systems. (Hardware isn't hard, usually.)