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Learning the bash Shell, 3rd Edition

Name: Learning the bash Shell, 3rd Edition
Author: Cameron Newham
ISBN: 9780596009656

by Cameron Newham

March 2005

Beginner

352 pages

16h 9m

English

O'Reilly Media, Inc.

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Preface
bash VersionsSummary of bash FeaturesIntended AudienceCode ExamplesChapter SummaryConventions Used in This HandbookWe’d Like to Hear from YouUsing Code ExamplesSafari EnabledAcknowledgments for the First EditionAcknowledgments for the Second EditionAcknowledgments for the Third Edition
1. bash Basics
1.1. What Is a Shell?1.2. Scope of This Book1.3. History of UNIX Shells1.3.1. The Bourne Again Shell1.3.2. Features of bash1.4. Getting bash1.5. Interactive Shell Use1.5.1. Commands, Arguments, and Options1.6. Files1.6.1. Directories1.6.1.1. The working directory1.6.1.2. Tilde notation1.6.1.3. Changing working directories1.6.2. Filenames, Wildcards, and Pathname Expansion1.6.3. Brace Expansion1.7. Input and Output1.7.1. Standard I/O1.7.2. I/O Redirection1.7.3. Pipelines1.8. Background Jobs1.8.1. Background I/O1.8.2. Background Jobs and Priorities1.9. Special Characters and Quoting1.9.1. Quoting1.9.2. Backslash-Escaping1.9.3. Quoting Quotation Marks1.9.4. Continuing Lines1.9.5. Control Keys1.10. Help
2. Command-Line Editing
2.1. Enabling Command-Line Editing2.2. The History List2.3. emacs Editing Mode2.3.1. Basic Commands2.3.2. Word Commands2.3.3. Line Commands2.3.4. Moving Around in the History List2.3.5. Textual Completion2.3.6. Miscellaneous Commands2.4. vi Editing Mode2.4.1. Simple Control Mode Commands2.4.2. Entering and Changing Text2.4.3. Deletion Commands2.4.4. Moving Around in the History List2.4.5. Character-Finding Commands2.4.6. Textual Completion2.4.7. Miscellaneous Commands2.5. The fc Command2.6. History Expansion2.7. readline2.7.1. The readline Startup File2.7.1.1. readline variables2.7.2. Key Bindings Using bind2.8. Keyboard Habits
3. Customizing Your Environment
3.1. The .bash_profile, .bash_logout, and .bashrc Files3.2. Aliases3.3. Options3.3.1. shopt3.4. Shell Variables3.4.1. Variables and Quoting3.4.2. Built-In Variables3.4.2.1. Editing mode variables3.4.2.2. Mail variables3.4.2.3. Prompting variables3.4.2.4. Command search path3.4.2.5. Command hashing3.4.2.6. Directory search path and variables3.4.2.7. Miscellaneous variables3.5. Customization and Subprocesses3.5.1. Environment Variables3.5.1.1. Terminal types3.5.1.2. Other common variables3.5.2. The Environment File3.6. Customization Hints
4. Basic Shell Programming
4.1. Shell Scripts and Functions4.1.1. Functions4.2. Shell Variables4.2.1. Positional Parameters4.2.1.1. Positional parameters in functions4.2.2. Local Variables in Functions4.2.3. Quoting with $@ and $*4.2.4. More on Variable Syntax4.3. String Operators4.3.1. Syntax of String Operators4.3.2. Patterns and Pattern Matching4.3.3. Length Operator4.3.4. Extended Pattern Matching4.4. Command Substitution4.5. Advanced Examples: pushd and popd
5. Flow Control
5.1. if/else5.1.1. Exit Status5.1.2. Return5.1.3. Combinations of Exit Statuses5.1.4. Condition Tests5.1.4.1. String comparisons5.1.4.2. File attribute checking5.1.5. Integer Conditionals5.2. for5.3. case5.4. select5.5. while and until
6. Command-Line Options and Typed Variables
6.1. Command-Line Options6.1.1. shift6.1.2. Options with Arguments6.1.3. getopts6.2. Typed Variables6.3. Integer Variables and Arithmetic6.3.1. Arithmetic Conditionals6.3.2. Arithmetic Variables and Assignment6.3.3. Arithmetic for Loops6.4. Arrays
7. Input/Output and Command-Line Processing
7.1. I/O Redirectors7.1.1. Here-documents7.1.2. File Descriptors7.2. String I/O7.2.1. echo7.2.1.1. Options to echo7.2.1.2. echo escape sequences7.2.2. printf7.2.2.1. Additional bash printf specifiers7.2.3. read7.2.3.1. Reading lines from files7.2.3.2. I/O redirection and multiple commands7.2.3.3. Command blocks7.2.3.4. Reading user input7.3. Command-Line Processing7.3.1. Quoting7.3.2. command, builtin, and enable7.3.3. eval
8. Process Handling
8.1. Process IDs and Job Numbers8.2. Job Control8.2.1. Foreground and Background8.2.2. Suspending a Job8.3. Signals8.3.1. Control-Key Signals8.3.2. kill8.3.3. ps8.3.3.1. System V8.3.3.2. BSD8.4. trap8.4.1. Traps and Functions8.4.2. Process ID Variables and Temporary Files8.4.3. Ignoring Signals8.4.4. disown8.4.5. Resetting Traps8.5. Coroutines8.5.1. wait8.5.2. Advantages and Disadvantages of Coroutines8.5.3. Parallelization8.6. Subshells8.6.1. Subshell Inheritance8.6.2. Nested Subshells8.7. Process Substitution
9. Debugging Shell Programs
9.1. Basic Debugging Aids9.1.1. Set Options9.1.2. Fake Signals9.1.2.1. EXIT9.1.2.2. ERR9.1.2.3. DEBUG9.1.2.4. RETURN9.1.3. Debugging Variables9.2. A bash Debugger9.2.1. Structure of the Debugger9.2.1.1. The driver script9.2.1.2. exec9.2.2. The Preamble9.2.3. Debugger Functions9.2.3.1. Commands9.2.3.2. Stepping9.2.3.3. Breakpoints9.2.3.4. Break conditions9.2.3.5. Execution tracing9.2.3.6. Debugger limitations9.2.4. A Sample bashdb Session9.2.5. Exercises

10. bash Administration
10.1. Installing bash as the Standard Shell10.1.1. POSIX Mode10.1.2. Command-Line Options10.2. Environment Customization10.2.1. umask10.2.2. ulimit10.2.3. Types of Global Customization10.3. System Security Features10.3.1. Restricted Shell10.3.2. A System Break-In Scenario10.3.3. Privileged Mode
11. Shell Scripting
11.1. What’s That Do?11.1.1. Comments11.1.2. Variables and Constants11.2. Starting Up11.3. Potential Problems11.4. Don’t Use bash
12. bash for Your System
12.1. Obtaining bash12.2. Unpacking the Archive12.3. What’s in the Archive12.3.1. Documentation12.3.2. Configuring and Building bash12.3.3. Testing bash12.3.4. Potential Problems12.3.5. Installing bash as a Login Shell12.3.6. Examples12.4. Who Do I Turn to?12.4.1. Asking Questions12.4.2. Reporting Bugs
A. Related Shells
A.1. The Bourne ShellA.2. The IEEE 1003.2 POSIX Shell StandardA.3. The Korn ShellA.4. pdkshA.5. zshA.6. Shell Clones and Unix-like PlatformsA.6.1. CygwinA.6.2. DJGPPA.6.3. MKS ToolkitA.6.4. AT&T UWIN
B. Reference Lists
B.1. InvocationB.2. Prompt String CustomizationsB.3. Built-In Commands and Reserved WordsB.4. Built-In Shell VariablesB.5. Test OperatorsB.6. set OptionsB.7. shopt OptionsB.8. I/O RedirectionB.9. emacs Mode CommandsB.10. vi Control Mode Commands
C. Loadable Built-Ins
D. Programmable Completion
Index
About the Author
Colophon
Copyright

Content preview from Learning the bash Shell, 3rd Edition

Chapter 12. bash for Your System

The first 10 chapters of this book looked at nearly all aspects of bash, from navigating the filesystem and editing the command-line to writing shell scripts and functions using lesser-known features of the shell. This is all very well and good, but what if you have an old version of bash and want the new features shown in this book (or worse yet, you don’t have bash at all)?

In this chapter we’ll show you how to get the latest version of bash and install it on your system, and we’ll discuss potential problems you might encounter along the way. We’ll also look briefly at the examples that come with bash and how you can report bugs to the bash maintainer.

Obtaining bash

If you have a direct connection to the Internet, you should have no trouble obtaining bash; otherwise, you’ll have to do a little more work.

The bash home page is located at http://www.gnu.org/software/bash/bash.html and you can find the very latest details of the current distribution and where to obtain it from there.

You can also get bash on CD-ROM by ordering it directly from the Free Software Foundation, either via the web ordering page at http://order.fsf.org or from:

The Free Software Foundation (FSF)
59 Temple Place - Suite 330
Boston, MA 02111-1307 USA

Phone: +1-617-542-5942
Fax: +1-617-542-2652
Email: order@fsf.org

Unpacking the Archive

Having obtained the archive file by one of the above methods, you need to unpack it and install it on your system. Unpacking can be done anywhere—we’ll ...

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