Welcome to LQ!
I'm a old UNIX guy myself. I've been using GNU/Linux since it's inception. I haven't had a UNIX licensed machine in years. I retired from the LAB back in 96 so I couldn't continue license costs. I continued with GNU/Linux an never turned back. I still use UNIX but only when clients or someone else guests me. Sure I could have continued with an account at the University but really didn't need the hassle to keep the account active. Plus some of my use is commercial thus violating license agreements with academia.
As for the security of your install look at chkroot
. You won't have the problem of M$ on a GNU/Linux install. But you should make sure to have a good firewall and possibly a means to check for rootkits. 'Tripwire
' is another means of protection.
You should minimize the services available on your machine. Just disable the services that you know that will not be used.
You can get a lot of reference online so here are a few links to aid you;
Linux Documentation Project
Rute Tutorial & Exposition
Linux Command Guide
Linux Newbie Admin Guide
Getting Started with Linux
These links and others can be found at 'Slackware-Links
' . More than just SlackwareŽ links!