concise style of this book provides important information on Unix, shell, and command utilities. documentation is clear and complete instructions and examples that are relevant and easy to follow. Gilly begins with a list, a full alphabet of the core Unix commands. The authors then include documentation of the shell, provide details about the shells Bourne, Korn, and C and documenting every command shell in a standard format. Gilly also includes a section on regular expressions as applied to grep, egrep, text editor, and various scripting languages. Furthermore, this book offers complete documentation of Emacs, ex, and vi, which prove the powerful editor command structure constant is difficult to learn.