I have been using Unix (specifically SUN Solaris SVR4/BSD) since 1990, started with normal programming works on Unix into Technical support for the SUN Microsystems hardware and O/S. Experienced covers installing O/S, installing/set-up application (commercial and Open-source), trouble-shooting hardware and software related and more.
Started playing with Linux since 2000, and now very comfortable with linux/bsd stuffs, major reason will be the setup costs can be very minimum compared to "branded" unix. Used a lot of open-source application in terms of installing, configuring and trouble-shooting problems. Experienced in handling training for small-group on Unix/linux/open-source application.