Classic Shell Scripting

I've scrolled through lots of books, there is so much information out there, but this book has a tendency to keep it simple and to the point. It has good illustrative examples that not only are useful but also serve as a good practice guide.

The purpose of this handy little book is to help someone who is working with Unix through the labyrinth of tools available and learn how and when to use them. It is important to note what is mentioned in the preface - "Throughout this book, we use the term Unix to mean not only commercial variants of the original Unix system, such as Solaris, Mac OS X, and HP-UX, but also the freely available workalike systems, such as GNU/Linux and the various BSD systems: BSD/OS, NetBSD, FreeBSD, and OpenBSD." I quote the book because the word "Unix" is about as descriptive as the word "car". The intended audience is anyone who is computer literate, already knows how to program, and is regularly faced with diverse problems in the workplace that must be solved with Unix tools. This book should give you a taste of which tool to turn to and when. This book can be divided basically into two halves. The first half is a tutorial on writing Unix scripts. The book starts with a brief history of the Unix language and the philosophy behind Unix tools. Slowly, each chapter builds up your skill at script writing. You are shown how to differentiate between shells, how to work with text extensively, how to use loops, pipelines, variables, and decision statements, and how to work with files. There are detailed example scripts at every step along the way. By the end of chapter seven, you should know enough about basic shell scripting to be dangerous. Starting in chapter 8, you are showed more application-related information. First, Chapter 8 shows and discusses some ready-made scripts for some tasks for which there is no out-of-the-box Unix solution. Some of the handy solutions shown are for path searching and automating software builds. Chapter 9 is a crash course on awk, and is aptly named. It is just enough to be dangerous. You learn how to solve common text processing problems with awk, but you'll need more resources to be really knowledgable. Chapter 10 explains the usage of common commands for listing files, modifying their timestamps, creating temporary files, finding files in a directory hierarchy, applying commands to a list of files, determining the amount of filesystem space used, and comparing files. Next there are two applied chapters showing you how to merge several databases and how to perform spellchecking by using scripting. Chapter 13 changes the subject a bit and talks about the concept of processes in Unix and how you can use their statistics to accomplish a number of monitoring and control tasks. Chapter 14 talks about problems you may run into if you try to take advantage of shell-language extensions, while Chapter 15 addresses the issue of writing secure scripts to the extent it is possible to do so. Writing man pages, and the basics of the Unix filesystem are the subjects of the last two chapters of the book. I would say it is a good modern introduction to the subject of shell scripting and Unix tools and how to use them. It doesn't dive deeply in

Great book. The emphasis is nicely split between actually using the shell itself and the whole supporting cast of unix tools (sed, awk, cut, join, sort etc.) The idea of carefully crafting solutions using the unix toolbox mindset is key. I also like the fact he doesn't try to teach to multiple shells, but first tries to emphasize portability by sticking mainly to a POSIX standard, and only later adds info about non standard shell topics. If I could only have one book on shell scripting, this would be it. The best description is 'Practical'.

This is the book that I have been waiting for years for. It's classic O'Reilly, but it's better than that. Even the O'Reilly books have fallen short of being truly useful for shell scripting. I think this was primarily because the authors have been thinking more about language fundamentals then about teaching useful things. This book is targeted towards teaching shell scripting through practical application. This is the shell scripting book to get.

This might be a great second book on shell scripting. Can serve as a valuable add on to "Learning Korn shell" from O'Reilly -- also a very strong book on shell scripting. The authors provide a lot of interesting and useful information that is difficult to find in other books. They devoted Ch 5 to piping and in 5.4 "Word List" they discuss famous Doug McIlroy alternative solution to Donald Knuth program of creating the list of the n most-frequent words, with counts of their frequency of occurrence, sorted by descending count from an arbitrary text file. The authors discuss many Unix tools that are used with shell (Unix toolbox). They provide a very good (but too brief) discussion of grep and find. Discussion of xargs (which is usually a sign on a good book on scripting) includes /dev/null trick, but unfortunately they do not mention an option -0n with which this trick makes the most sense. One of the best chapters of the book is Ch. 13 devoted to process control. Also good is Chapter 11 that provides a solution to pretty complex and practically important for many system administrators task of merging passwd files in Unix. It provides a perfect insight into solving real sysadmins problems using AWK and shell. Shortcomings are few. in "5.2. Structured Data for the Web" the authors should probably use AWK instead of SED. Also XML processing generally requires using a lexical analyzer, not regular expressions. Therefore a tag list example would be better converted to something simpler, for example generating C-tags for vi.