My 2 cents. (Score 1)

I've been a UNIX sysadmin for about 18 months now at a University in South-Western Ontario. I went here to learn how to do it.

The best advice I could give is to eat, sleep and sh*t UNIX. When I finished up school, I spent several weeks playing around on a home network, configuring things like NFS, Samba and ssh, all the while gaining a more thorough understanding of both specific applications and the ways in which they integrate with the underlying OS. Tell your boss that you want a UNIX workstation, or if that falls by the wayside, load Linux/*BSD on a PC. I find it much easier to admin UNIX by using a UNIX box rather than running SecureCRT or PuTTy off Windows. Besides which, you'll have more opportunity to use the OS on a regular basis. You'll also become accustomed to patching your system.

Don't expect to become an uber-admin overnight. Starting green (like I did), you might not be trusted to admin everything UNIX, as the large, mission-critical Solaris/Oracle servers surely aren't proving grounds for a newbie. Prove yourself first, and as you mature into a professional admin, your skills will be noticed and put to good use accordingly. I'm more established (and trusted) now, but in my earlier days, the systems I supported weren't terribly important (mostly dev), and as such I could work without beads of sweat on my forehead.

WATCH EVERY MOVE YOU MAKE! I cannot impart this enough. Don't allow yourself to become lazy and careless, for as a result you might end up typing `kill' in place of `ps -ef' and quickly cut-n-paste a PID without thinking. Yup, I killed an appserver this way. Don't do things as root that can be done just as easily as an unprivileged user. Drill that into yourself from the get-go. You cannot be careful enough.

Working for a Uni is incredible. The pay is good; although it's not as good as the private sector, the working conditions more than make up for it. I've got my own office (at 21 yrs old, no less!) down the hall from several admins who have proven to be awesome sources of knowledge for a young sysadmin with far too many questions. Large, heterogeneous computing environment, flex hours up the wazoo, two hour lunches, etc, etc.

You're guaranteed to learn a ton, but do maintain a sense of humility. The more you learn, the more you realize how little you truly know in the grand scheme of things.