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)

Shell metacharacters

So far, all of our examples of commands and arguments have been single unquoted shell words. However, there is a set of metacharacters that have a different meaning to Bash, and trying to use them as part of a word causes problems.

For example, suppose you want to create (touch) a new file named important file. Note that there's a space in the name. If you try to create it as follows, you get unexpected results:

$ touch important file

If we list the files in the directory after running this, using ls -1 to put all the names on separate lines, we can see we've actually created two files; one named important, and one named file:

$ ls -1

This happened because the space between the two words separated them into two separate arguments. Space, tab, and newline are all metacharacters. So are | (pipe), & (ampersand), ; (semicolon), ( and...