3.2 Shell Commands

A simple shell command such as echo a b c consists of the command itself followed by arguments, separated by spaces.

More complex shell commands are composed of simple commands arranged together in a variety of ways: in a pipeline in which the output of one command becomes the input of a second, in a loop or conditional construct, or in some other grouping.

Simple Commands:    The most common type of command.
Pipelines:    Connecting the input and output of several

commands.

Lists:    How to execute commands sequentially.
Compound Commands:    Shell commands for control flow.
Coprocesses:    Two-way communication between commands.
GNU Parallel:    Running commands in parallel.