Customer Reviews

Pro Bash Programming (Expert's Voice in Linux)

5 star:		(6)
4 star:		(0)
3 star:		(1)
2 star:		(1)
1 star:		(0)

 

 

I have been looking to update my Kochan and Wood, as it is a bit dated (Hayden Books, 1990).

Over the past couple years I have considered both for sale published works and free online sources for an updated book on shell programming, as Bash has introduced so many new features in the past years.

Though the description states that beginners can use this book, it does progress quickly into more advanced topics.

The positive reviews here and the general excellent quality of Apress books led me to buy this, and I was not disappointed.

In addition to detailing shell features and showing how to use them, Johnson has done something that is not frequently done - he has shown *why* I might want to use a feature.

Chapter 6 for example has excellent explanations of Parameter expansion. Wondering why I might want to use ${VAR:+Alternate} Johnson shows how it is useful. In this case I was able to immediately use it in a script that was being developed, simplifying it greatly.

Kudos for a job well done.

Considering the critical role Bash has in the installation and operation of Linux distributions and thereby its ubiquity, Bash as a programming language is frequently overlooked by programmers. The author of Pro Bash Programming has done a creditable job in providing the wherewithal for everyone from beginners to expert shell programmers to write more powerful and efficient scripts using Bash, as he takes you through a fast paced coverage of bash's capabilities. Along the way, many useful, well explained and commented practical scripts are provided, many of which can be used to build and test your own scripts. The author claims that while he used to use C when he needed extra speed, that was several years ago and he now does everything in the shell. This book shows how.

The 230 page book is divided into the 15 chapters below, with each chapter ending with a summary of the commands covered and some well chosen exercises.

1 Hello, World! Your first Shell Program
- how to create and run a script and establish good scripting habits
2 Input, Output and Throughput
- echo, printf, read and IO streams
3 Looping and Branching
- tests, conditional execution, looping constructs
4 Command-Line Parsing and Expansion
- quoting, brace, tilde, parameter, variable arithmetic and pathname expansion, command and process substitution, word splitting and parsing with getops
5 Parameters and Variables
- variable scope (essential reading), positional parameters and expansion using patterns, arrays - indexed and associative
6 Shell Functions
- how to define, use and set exit codes, use of compound commands, creation and use of function libraries
7 String Manipulation
- concatenation, processing character by character, case conversion, inserting, overlaying and trimming strings
8 File Operations and Commands
- reading, use of external commands, regular expressions with grep, sed and awk, file name expansion options
9 Reserved Words and Builtin Commands
- good coverage of builtin commands, particularly read (including into arrays) plus a very informative section on how to use builtin commands correctly
10 Writing Bug-Free Scripts and Debugging the Rest
- good scripting programming recommendations for bug free code plus a test and debug example
11 Programming for the Command Line
- manipulating the directory stack, filesystem and miscellaneous functions, managing man pages, games!
12 Runtime Configuration
- command line options and arguments, menus, configuration files, scripts with several names, using environment variables
13 Data Processing
- sorting and searching arrays, various ways of reading arrays into memory, grids (string and two dimensional), data file formats
14 Scripting the Screen
- using the screen as a blackboard or canvas, rendition modes and colours, text scrolling - rolling dice example
15 Entry-Level Programming
- single key entry, use of author's key-funcs library, sanity checking, form entry, reading the mouse!

Appendix: Shell Variables
- alphabetic listing of (1) variables set by bash and (2) variables used by bash

One of the strengths of this book is that the author explains the fastest way to accomplish many standard programming tasks through the appropriate choice of one of the many different bash methods available, including the choice between builtin bash commands and external commands. I found chapter 9 particularly interesting here. Chapter 7 shows how effective bash is at string manipulation with the right techniques - amazing! While the book covers bash 4.0 and often uses non POSIX extensions, those unable to use bash 4.0 or constrained to POSIX compliant code are not forgotten, with the author providing alternatives that work within these constraints.

Where a subject is introduced in an early chapter and expanded on later, the author thoughtfully provides the forward reference. Source code for the included scripts is available from the publisher's webpage for this book at [...]

The 10 page index works reasonably well, but you may find it worthwhile grabbing the companion eBook so you can directly search through the book to make the best use of it as a reference source. If you buy the dead tree version, the eBook is available on-line for $10 until April 2010 direct from the publisher.

I can recommend this book to anyone that can benefit from automating repetitive shell based tasks in Linux but isn't sure how best to go about it. The included scripts and wealth of tips on how to avoid common bash coding problems will provide you with a quick return on your investment.


Neil Matthews

Full disclosure: I was the technical reviewer for this book, and I admit my opinion may be biased. However, I was a just technical mercenary hired by the publisher so there is no financial benefit to me if the book does well or not.

Is author Chris F. A. Johnson pushing an agenda? You bet he is and that is a good thing. His agenda isn't hidden; he succinctly states it in the introduction:

"While most shell programs do call external utilities, a lot of programming can be done entirely in the shell. Many scripts call just one or two utilities for information that is used later in the script. Some scripts are little more than wrappers for other commands such as awk, grep, or sed. This book is about programming in the shell itself. There's a sprinkling of the second type, where the script gets information (such as the current date and time) and then processes it. The third type gets barely more than a cursory nod."

Resist the urge to call awk, grep, sed, perl or another Linux tool first; this book teaches the Bash shell's prgramming capabilities. Why call an external program when the shell can do the work for you?

Should this be your first Bash programming book? Not if you require lots of syntactic hand holding. But if a motivated and clever beginner masters the first 10 chapters of this book, that beginner is on their way to becoming an expert. You will learn how to create functions, deal with files, parse strings, etc - correctly!

There might also be something here for the expert. I've been creating *nix shell scripts for a long time, and I admit to being set in my programming ways. After reviewing this book, I changed the way I now parse and manipulate strings.

This book taught me bash better than any other guide I've ever encountered (including everything online) and single-handedly gave me what I needed to complete a commercial project: a complete website deployment app and a fully automatic SQL change management synchronizer.

This book goes from beginner to advanced real fast.
So it is good for beginners and advanced people.
Some things are not that easy to understand but I
still give it 5 stars! I will read it over again
until I understand.

I am a long-time user of Linux, and so of Bash. I own several books on Bash programming, but I have always had trouble with Bash syntax, and I was looking forward to a book that treated Bash as a programming language, which is what the blurb promised. Sorry, this is NOT an explanation of Bash as a programming language.

The first thing I noticed about the book is that it is physically hard to read - small, hard to read type on large pages. This may not bother other readers with younger eyes.

The second thing I noticed was that the book does not talk about the syntax of Bash statements. My biggest problem writing Bash scripts is getting the spaces where they belong. A book that presents Bash as a language should certainly explain the basic syntax of statements, including where the spaces go and don't go - that's key to syntax, isn't it? Sorry, not here.

So what's left? A book, not terribly well written, which talks about Bash programming techniques. Fine, but there are good books already out there. I would suggest "Classic Shell Scripting" from O'Reilly. It's long, but it covers not only Bash itself, but command line programs like awk which can be used inline. I find it easy to read, both physically and stylistically. I have also found "Linux Shell Scripting with Bash" from Developer's Library to be helpful.

Best book I've seen on BASH and I have seen quite a few. This is exactly the book I have been looking for.

BASH is more than "just a scripting language"; I've always seen that but could not find a book that would teach it that way. BASH is often presented to Windows users as a more powerful "DOS batch program" - NO! I like very much that it is treated here as the powerful and complete programming language it is, and teaches this within a couple hundred pages. It is not a 900 page book that I know I will never finish. The book is shown as 350 pages but chapter to chapter its 204 pages - easily digestible. This is the book I am spending the summer with.

The bash shell is a complete programming language, not merely a glue to combine external Linux commands (as it is all too often presented). 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/Linux lore, you can write professional bash programs through standard programming techniques.

What to learn BASH? Want to learn the BASH programming language? Get this book. I am very happy. I also had my local library buy it so it can get into the hands of more people (who, like me, will ultimately buy their own copy). Thank you Chris!

I bought this for my husband and his opinion is that the book contains helpful information that could be better organized and that the author is 'pushing an agenda' so he would give the book three stars.