While it assumed that the reader has a familiarity of Unix, a brief
overview can only enhance previous knowledge.
Unix comes in a variety of constantly changing flavors (SUNOS, HPUX,
BSD and Solaris, just to name a few).
Each of these Unix types will have small variations from all of the
This may seem a bit discouraging at first, but in reality each version
of Unix has more in common with all of the others than differences.
ls, for example, will give a listing of the current
directory in any Unix environment.
The changes or semantics local to any particular brand of Unix should
be explained in the
man pages that come with that particular
The purpose of this book is not to explore the differences between
differnt Unix flavors but rather to assume that they are all
equivalent and look at how the different shells behave.
Hence, the rest of the book assumes a kind of generic Unix operating
system (except where explicitly stated otherwise).