深入探索Linux Shell脚本编程指南

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"Advanced Bash-Scripting Guide - Linux Shell编程指南" 《Advanced Bash-Scripting Guide》是一本深入探讨Linux shell脚本艺术的专业书籍，由Mendel Cooper撰写。该书面向的是没有编程或脚本经验的读者，但随着内容的推进，它逐渐引领读者达到中级至高级的编程水平，同时在讲解过程中穿插了UNIX智慧和传统的知识。这本书不仅可以用作教科书，也可以作为自我学习的手册、shell脚本技术的参考和知识来源。书中包含的练习和大量注释示例鼓励读者积极参与，因为真正掌握脚本编写的方法就是通过编写脚本来实践。本书特别适合用作课堂教学，介绍编程概念的入门教材。作者将此书献给了Anita，他生命中的魔法源泉。目录概览： 1. Shell编程！ - 第一章引导读者进入shell脚本的世界，介绍基础概念和语法。 2. 以一个响亮的“Bang”开始... - 第二章主要讨论如何启动脚本，解释了如何在脚本开头使用“#!”（shebang）行来指定解释器。在《Advanced Bash-Scripting Guide》中，读者会学到以下关键知识点： 1. **Shell基础知识**：包括变量定义、赋值、字符串操作、条件测试、流程控制语句（如if、for、while循环）等。 2. **函数与数组**：如何创建和使用自定义函数以及处理多值的数组。 3. **命令替换和重定向**：理解命令的输出如何被重定向到文件，以及如何使用管道（pipe）连接多个命令。 4. **正则表达式**：在shell脚本中使用正则表达式进行文本匹配和模式操作。 5. **文件和目录操作**：包括文件的创建、删除、复制、移动，以及目录的管理。 6. **错误处理和调试**：如何捕获并处理脚本运行时的错误，以及调试技巧。 7. **函数和脚本参数**：如何传递参数给脚本并使用它们。 8. **脚本优化和性能**：提高脚本效率的策略和最佳实践。 9. **脚本调试和测试**：如何构建测试用例，确保脚本的正确性。此外，书中还涵盖了shell脚本的高级特性，如进程控制、信号处理、子shell、函数库、陷阱处理等。每一章都伴随着详细的示例和练习，帮助读者巩固所学知识，提升shell编程技能。《Advanced Bash-Scripting Guide》是一本全面而深入的Linux shell编程教程，无论你是初学者还是有一定经验的开发者，都能从中获益匪浅，提升自己的shell编程能力。

bash$ cp /home/bozo/current_work/junk/* .

Copy all the "junk" files to $PWD.

"dot" character match. When matching characters, as part of a regular expression, a "dot" matches a

single character.

partial quoting [double quote]. "STRING" preserves (from interpretation) most of the special

characters within STRING. See Chapter 5.

full quoting [single quote]. 'STRING' preserves all special characters within STRING. This is a

stronger form of quoting than "STRING". See Chapter 5.

comma operator. The comma operator [15] links together a series of arithmetic operations. All are

evaluated, but only the last one is returned.

let "t2 = ((a = 9, 15 / 3))"

# Set "a = 9" and "t2 = 15 / 3"

The comma operator can also concatenate strings.

for file in /{,usr/}bin/*calc

# ^ Find all executable files ending in "calc"

#+ in /bin and /usr/bin directories.

if [ -x "$file" ]

then

echo $file

done

# /bin/ipcalc

# /usr/bin/kcalc

# /usr/bin/oidcalc

# /usr/bin/oocalc

# Thank you, Rory Winston, for pointing this out.

,, ,

Lowercase conversion in parameter substitution (added in version 4 of Bash).

escape [backslash]. A quoting mechanism for single characters.

\X escapes the character X. This has the effect of "quoting" X, equivalent to 'X'. The \ may be used to

quote " and ', so they are expressed literally.

See Chapter 5 for an in-depth explanation of escaped characters.

Filename path separator [forward slash]. Separates the components of a filename (as in

/home/bozo/projects/Makefile).

This is also the division arithmetic operator.

command substitution. The `command` construct makes available the output of command for

assignment to a variable. This is also known as backquotes or backticks.

Advanced Bash-Scripting Guide

Chapter 3. Special Characters 10

Edited by Foxit Reader

For Evaluation Only.

This applies to regular files, not pipes, symlinks, and certain special files.

May be used to begin a comment line, although this is not recommended. Using # for a comment

turns off error checking for the remainder of that line, so almost anything may appear in a comment.

However, this is not the case with :.

: This is a comment that generates an error, ( if [ $x -eq 3] ).

The ":" also serves as a field separator, in /etc/passwd, and in the $PATH variable.

bash$ echo $PATH

/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/sbin:/usr/sbin:/usr/games

reverse (or negate) the sense of a test or exit status [bang]. The ! operator inverts the exit status of

the command to which it is applied (see Example 6-2). It also inverts the meaning of a test operator.

This can, for example, change the sense of equal ( = ) to not-equal ( != ). The ! operator is a Bash

keyword.

In a different context, the ! also appears in indirect variable references.

In yet another context, from the command line, the ! invokes the Bash history mechanism (see

Appendix K). Note that within a script, the history mechanism is disabled.

wild card [asterisk]. The * character serves as a "wild card" for filename expansion in globbing. By

itself, it matches every filename in a given directory.

bash$ echo *

abs-book.sgml add-drive.sh agram.sh alias.sh

The * also represents any number (or zero) characters in a regular expression.

arithmetic operator. In the context of arithmetic operations, the * denotes multiplication.

** A double asterisk can represent the exponentiation operator or extended file-match globbing.

test operator. Within certain expressions, the ? indicates a test for a condition.

In a double-parentheses construct, the ? can serve as an element of a C-style trinary operator, ?:.

(( var0 = var1<98?9:21 ))

# ^ ^

# if [ "$var1" -lt 98 ]

# then

# var0=9

# else

# var0=21

# fi

In a parameter substitution expression, the ? tests whether a variable has been set.

wild card. The ? character serves as a single-character "wild card" for filename expansion in

globbing, as well as representing one character in an extended regular expression.

Advanced Bash-Scripting Guide

Chapter 3. Special Characters 12

Edited by Foxit Reader

For Evaluation Only.

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深入探索Linux Shell脚本编程指南

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abs-guide----Advanced Bash-Scripting Guide

shell编程入门(abs-guide-3.chm)

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abs-guide-3.7.tar.tar

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