How to use and customise your shell. Introduces shell scripting.

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Product Description

O'Reilly's bestselling book on Linux's bash shell is at it again. Now that Linux is an established player both as a server and on the desktop Learning the bash Shell has been updated and refreshed to account for all the latest changes. Indeed, this third edition serves as the most valuable guide yet to the bash shell. As any good programmer knows, the first thing users of the Linux operating system come face to face with is the shell the UNIX term for a user interface to the system. In other words, it's what lets you communicate with the computer via the keyboard and display. Mastering the bash shell might sound fairly simple but it isn't. In truth, there are many complexities that need careful explanation, which is just what Learning the bash Shell provides. If you are new to shell programming, the book provides an excellent introduction, covering everything from the most basic to the most advanced features. And if you've been writing shell scripts for years, it offers a great way to find out what the new shell offers. Learning the bash Shell is also full of practical examples of shell commands and programs that will make everyday use of Linux that much easier. With this book, programmers will learn: How to install bash as your login shell The basics of interactive shell use, including UNIX file and directory structures, standard I/O, and background jobs Command line editing, history substitution, and key bindings How to customize your shell environment without programming The nuts and bolts of basic shell programming, flow control structures, command-line options and typed variables Process handling, from job control to processes, coroutines and subshells Debugging techniques, such as trace and verbose modes Techniques for implementing system-wide shell customization and features related to system security

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Product Details

• Amazon Sales Rank: #166037 in Books
• Published on: 2005-03-29
• Original language: English
• Number of items: 1
• Binding: Paperback
• 333 pages

Meg Golding, linuxchix.org, May 2002
Learning the bash Shell" has kept a place no further than arms-length from my computer. No other technical book can say the same.

Rebecca Walter, linuxchix.org
"...."Learning the bash Shell" has kept a place no further than arms-length from my computer. No other technical book can say the same...."

Rebecca Walter, Linuxchix.org
"Learning the bash Shell" has kept a place no further than arms-length from my computer. No other technical book can say the same.

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Customer Reviews

A useful aid to understanding the Bash Linux/ Unix shell.
This book provides a useful text on the capabilities of the Bash shell for Linux / Unix. The concept of the Unix shell is very much bigger than just the command prompt that it may resemble if you are a "recovering" DOS user. Understanding of the role and capabilities of the shell is an essential prerequisite for effectively harnessing the power of Linux/ Unix and certainly justifies a book to itself. The Bash shell is a particularly powerful and modern shell program which has the advantage of being freely distributable as part of the GNU project, and as such is probably the most widely used shell program in the Linux world. As such if you have no prior loyalties to another flavour shell - I suggest you learn this one. The book will certainly help you achieve this .

For beginners...
Traditional shell scripts are horrible. They are not nice languages with orthogonal instruction sets: they have grown organically, and inconsistently. Quotes, double-quotes, and escaped characters are often needed to slip something past one parsing layer to get it to another one.
Chapter one starts off describing what a terminal session actually is, so this is aimed at real beginners.

If you are a beginner, and you are able to chose your scripting language for your job, you might want to look at some of the more recent languages, such as 'python'. They are more regular, and easier to learn and maintain.

Anyway, back to the book. There are things you shouldn't do in a book that may be uses as an introduction and a reference. You should not give examples of code with bugs in, that you explain in the following chapter (ta-daa, aren't I clever?!). You should not give tables of functions or commands unless you list all the commands. If there is an exception to a rule, then you should at least mention it even if you haven't covered that case yet, or, better still, re-arrange the book so the exceptions are explicable. You must resist the urge to surprise the reader: this is shell scripts, and the reader will probably have had their fill of surprises. Last of all, and a personal one this, lay off the Lewis Carroll, please?

You need to be ultra-careful about quotes. When "@" appears in the text, does this mean a string of one character or three? Can you see whether the quotes are in heavy type?

You need to be really careful to distinguish what is 'in' the shell, and what commands and variables are outside it. Pattern matching is a key part of the shell, so regexps ought to be explained in some detail. The simple demo scripts should not have 'ed' and 'sed' commands stuck in without saying where they came from.And why not mention the debug flag before chapter 9?

There are some dubious comments about programming style. Is it really bad to use the 'break' statement in a loop? Is ' && ' really an obscure and unnecessary way of doing command2 if command1 fails? - I find it neat and compact.

This is a pity, because there are some good bits. The flow diagram on p178 and the attendant text about how command lines are processed is good (well, right up to the "-and it's not the whole story!", but you get the idea). But, for completeness, I reckon if there is something I want to look up about the bash shell, I am going to use my old Korn shell book rather than this book.