Book Image

Bash Quick Start Guide

By : Tom Ryder
Book Image

Bash Quick Start Guide

By: Tom Ryder

Overview of this book

Bash and shell script programming is central to using Linux, but it has many peculiar properties that are hard to understand and unfamiliar to many programmers, with a lot of misleading and even risky information online. Bash Quick Start Guide tackles these problems head on, and shows you the best practices of shell script programming. This book teaches effective shell script programming with Bash, and is ideal for people who may have used its command line but never really learned it in depth. This book will show you how even simple programming constructs in the shell can speed up and automate any kind of daily command-line work. For people who need to use the command line regularly in their daily work, this book provides practical advice for using the command-line shell beyond merely typing or copy-pasting commands into the shell. Readers will learn techniques suitable for automating processes and controlling processes, on both servers and workstations, whether for single command lines or long and complex scripts. The book even includes information on configuring your own shell environment to suit your workflow, and provides a running start for interpreting Bash scripts written by others.
Table of Contents (10 chapters)

Simple commands

At an interactive Bash prompt, you can enter a command line for Bash to execute. Most often while in interactive mode, you would issue only one simple command at a time, ending each command with Enter. You would then wait for each command to finish before entering the next one, examining any output or errors that it passes to your terminal after each command.

A simple command consists of at least a command name, possibly with one or more arguments, each separated by at least one space. The full definition can also include environment variable assignments and redirection operators, which we'll explore in later chapters.

Let's consider the following command:

$ mkdir -p New/bash

This simple command consists of three shell words:

  • mkdir: The command name, referring to the mkdir program that creates a directory
  • -p: An option string for mkdir that specifies...