The bash shell is a complete programming language, not merely a glue to combine external Linux commands. By taking full advantage of shell internals, shell programs can perform as snappily as utilities written in C or other compiled languages. And you will see how, without assuming Unix lore, you can write professional bash 4.0 programs through standard programming techniques.
Jumps around, advances quickly without adequate explanation, and assumes you already know how to operate in vi and bash. I supplemented this with other books (and a lot of googling) that provided a better grounding in bash. Skip this and look for the O’Reilly series or another alternative.
I wasn't expecting a ton from this book since it's not a reference nor is it very lengthy, so I was happy that several of my blindspots were addressed (in addition to clarifying some tricks and custom functions that are bound to save me time in the long-run). Wish I had read it years ago, but could've done without the chapters on grid games and terminal mouse events.