3. Basic Shell Features

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, and the rules for evaluation and quoting are taken from the POSIX 1003.2 specification for the `standard' Unix shell.

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.

3.1 Shell Syntax		What your input means to the shell.
3.2 Shell Commands		The types of commands you can use.
3.3 Shell Functions		Grouping commands by name.
3.4 Shell Parameters		Special shell variables.
3.5 Shell Expansions		How Bash expands variables and the various expansions available.
3.6 Redirections		A way to control where input and output go.
3.7 Executing Commands		What happens when you run a command.
3.8 Shell Scripts		Executing files of shell commands.