UNIX has been evolving feverishly for close to 30 years, sort of like bacteria in a cesspool - only not as attractive. As a result, many different varieties of UNIX have existed along the way. Although they all share numerous characteristics, they differ just enough that even experienced users are tripped up by the differences between versions. If you're like most UNIX users, a zealot stopped at your desk, connected your terminal or workstation, gave...