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, The rules for evaluation and quoting are taken from the POSIX 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.

Shell Syntax	What your input means to the shell.
Shell Commands	The types of commands you can use.
Shell Functions	Grouping commands by name.
Shell Parameters	How the shell stores values.
Shell Expansions	How Bash expands parameters and the various expansions available.
Redirections	A way to control where input and output go.
Executing Commands	What happens when you run a command.
Shell Scripts	Executing files of shell commands.