沙盒

Bash is an acronym for ‘Bourne-Again SHell’. The Bourne shell is the traditional Unix shell originally written by Stephen Bourne. All of the Bourne shell builtin commands are available in Bash, The rules for evaluation and quoting are taken from the POSIX specification for the ‘standard’ Unix shell.

Bash是‘Bourne-Again SHell’的首字母缩写。Bourne shell是传统Unix shell，它诞生之初是有Stephen Bourne写就的。所有Bourne shell的内置命令在Bash中都是可用的，其评估和引用规则取自POSIX规范的Unix shell ‘standard’。

This chapter briefly summarizes the shell’s ‘building blocks’: commands, control structures, shell functions, shell parameters, shell expansions, redirections, which are a way to direct input and output from and to named files, and how the shell executes commands.

本章简述了shell的‘building blocks’（构造块）：命令、控制结构、shell函数、shell 参数, shell 扩展, redirections（重定向），它是一种基于命名文件的直接输入和输出方法，以及shell怎样执行命令。

Shell Syntax:	What your input means to the shell. 对shell来说你输入的是什么？
Shell Commands:	The types of commands you can use. 你可以使用的命令。
Shell Functions:	Grouping commands by name. 按名称分组的命令。
Shell Parameters:	How the shell stores values. shell如何存储值。
Shell Expansions:	How Bash expands parameters and the various expansions available. Bash如何扩展参数以及可用的扩展。
Redirections:	A way to control where input and output go. 控制输入和输出地的方法。
Executing Commands:	What happens when you run a command. 当你运行一个命令时发生了什么？
Shell Scripts:	Executing files of shell commands. shell命令的执行文件。