Classic Shell Scripting: Hidden Commands That Unlock the Power of UNIX

Great book for beginners!

内容に目を通すまもなく‥すぐ盗難にあってしまいました。‥そういったわけで、内容はわからないのですが‥きっと素晴らしすぎる内容で、（宗教団体経由で？？）韓国あたりに、送られていったのかもしれません。‥二千円台で、購入したのに‥購入しなおそうかと思ったのですが‥価格が二倍近くに上がっていたようでした。

Me ha gustado mucho el libro porque desde el inicio da un breve review de algunos conceptos muy interesantes para que se entre en contexto a la par respecto al tema. También tiene muy bueno ejemplos y conforme se va avanzando te das cuenta de que has aprendido muchas cosas interesentates Muy recomendable, también no importa que vayas comenzando con shell scripting, todo está muy bien explicado

"Classic Shell Scripting" by Arnold Robbins and Nelson H. F. Beebe is a decent text on portable shell scripting, which also contains a fair amount of awk. Though written in tutorial form, it explicitly assumes that the reader knows how to use the shell interactively and, as I show below, in some cases implicitly assumes that the reader already knows the basics of shell scripting.The Good: Robbins and Beebe have created a pedagogically sound book which contains tables, fascinating digressions, sidebars (with major options on tools, along with caveats), an annotated bibliography, as well as a glossary. The book can be read straight through, since each chapter builds on the preceding ones, but the aforementioned resources are especially handy when using this book as a reference. Were it not for the tables and sidebars it would be difficult to look up things like how to set the field separator in different tools (-t in sort, -d in cut, -F in awk) or how to ensure case-insensitivity (-i in grep, -f in sort). The topics the authors cover throughout the book are interesting, but the real meat is in chapters 3, 6, 7, 9, 10, which discuss regular expressions, sed, awk (Robbins is the maintainer of gawk and also the co-author/author of books on awk), control flow, command evaluation, and file manipulation. Most of the other chapters are applications of the topics introduced up to that point, and serve to drive home the lessons already learned (though there are pleasant exceptions to this pattern, e.g. the section on crontab in ch. 13, or the material on the Unix filesystem in Appendix B). The writing is generally relaxed and at times borderline silly, e.g. "exit 42 #Return the answer to the ultimate question" or "root) nasty stuff here #Danger Will Robinson, danger!". Importantly, the entire book is focused on scripting that is compatible with the POSIX standard(s) (e.g., the authors prefer printf to echo) -- it is similar in that sense to Peter Seebach's book on portable shell scripting from Apress. Apart from the pointers on the behavior of different shells scattered throughout the volume, the authors have also devoted ch. 14 to portability gotchas and shell-language extensions.The Bad: despite the tutorial nature of this text, it does have a few pedagogical flaws. These include the use of concepts before they are introduced (e.g. here-documents are used in ch. 4 but are mentioned by name only in ch. 5; the ${varname:-word} operator is used in ch. 5 but is not defined until ch. 6; the authors use >&2 three times in ch. 6 before pointing out that they will explain it in ch. 7). Such minor slip-ups extend to the use of concepts that are just not explained anywhere in the book (e.g. in ch. 3 the d command in sed, or in ch. 5 the -c option in grep). In yet other cases, the authors simply do not practice what they preach (e.g. in ch. 7 they recommend $() for command substitution, but then use `` in all but one of the examples in chapter 8, titled "Production Scripts"). On a different note, using this volume as a reference is not as easy as it should be. Tracking down an explanation months after you've finished reading the book can be frustrating, as I will illustrate with a specific example: the index entry for globbing says "see pathname expansion"; going to the index entry for pathname expansion we are pointed only to p. 496 (the glossary entry for that term), but not to any sections in any of the chapters. In the glossary entry on p. 496 we are told that globbing a.k.a. pathname expansion is also called wildcarding. Heading back to the index, no entry for wildcarding is to be found; there's an entry for wildcard expansion, instead, which looks relevant. Unfortunately, that entry not only points to irrelevant sections, but also ends with the inimitable "see also pathname expansion". All the while, subsection 7.5.2 is titled "Wildcarding", but you wouldn't get there simply by using the index. Sadly, the table of contents is similarly unhelpful in this context, since it includes sections, but not subsections.This book could be shorter, but it's still worth reading. I especially enjoyed the sections on regular expressions and on awk. As already explained, readers who know nothing about shell scripting may find this a difficult read, so they might want to first go over "Learning the bash shell" by Newham & Rosenblatt or a similar volume. Finally, access to an ebook version can make up for the deficiencies of the index when using Robbins' & Beebe's text as a reference. All in all, 4.5 stars.Alex Gezerlis

This book is well paced and written. The authors manage to write in a very approachable way without missing any of the essential, and without patronising the reader.The title may mislead some into thinking that this book covers only scripting or is not suitable for starting to learn the *NIX shells. Nothing could be further from the truth. Taking the reader through the classic tools of unix, the authors then show how to bring those tools together and how to build continually more complex programs.Also appreciated are the examples throughout the book. These examples, unlike some similar titles, are there in just the right amount. You don't feel swamped by pages and pages of code, nor lost with nothing to demonstrate what is being said. The examples are always relevant, allowing you to learn important principles and start writing your own code.Overall, even if advanced users might not benefit as much from this book, it is still highly recommended read for anybody interested in using the power of the unix shell, either totally new users to the command line, or seasoned users with more experience. And surprisingly, This book remains accessible to both.