Unix in easy steps

Mike McGrath

• Publisher: In Easy Steps Limited
• Year: 2014
• Print ISBN: 9781840786224
• eBook ISBN: 9781840786736
• Topic: Informatik
• Subtopic: Betriebssysteme

Unix in Easy Steps instructs you how to use the BASH command-line interface and how to employ BASH's powerful programming abilities. Complete examples illustrate each aspect with colorized source code and full-color screenshots depict the actual output.The book begins by demonstrating BASH commands for system navigation and file manipulation so you can quickly become familiar with the command-line interface. It explains all the BASH basics before moving on to describe advanced features such as command history, command-line editing, and environment customization. It then introduces BASH programming with examples of flow control, command switches, input/output, job control, and program debugging — allowing you to create your own executable programs by copying the book's examples. Unix in Easy Steps has an easy-to-follow style that will appeal to users who are completely new to Unix-based operating systems, casual users who wish to expand their knowledge of their computer system, and those wanting to learn programming skills by writing useful shell scripts. It also appeals to the student who is studying programming at school or college and those seeking a career in computing and need a fundamental understanding of the BASH interpreter on Unix-based operating systems.

1

Getting started

Welcome to the exciting world of Unix. This chapter introduces the Bash command interpreter shell and demonstrates essential basic commands.

Introducing Unix

Discovering the shell

Understanding commands

Navigating directories

Dealing wildcards

Recognizing metacharacters

Quoting phrases

Getting help

Summary

Introducing Unix

Unix is a multi-user, multi-tasking computer operating system developed at AT&T’s Bell Labs. Way back in the mid 1960s Bell Labs, the Massachusetts Institute of Technology and General Electric co-developed a mainframe multi-tasking operating system named “Multics”. The Multics operating system became large and complex so Bell Labs withdrew from the project. A group from Bell Labs, notably Brian Kernighan and Dennis Ritchie, wanted to create something with many of the same multi-tasking capabilities but simpler to use. They named it “Unix” as a joke, saying “whatever Multics is many of, Unix is just one of”.

In 1973 Kernighan and Ritchie created the “C” high-level programming language and rewrote Unix in their new language. This was a huge leap from the assembly code used in all other operating system development at that time. The migration from assembly code to the C language produced much more portable software that was easily ported to other computing platforms. AT&T made the Unix source code available to universities, which created a great amount of academic interest, particularly at the University of California, Berkeley. Their Computer Science Research Group added new capabilities then released their version of Unix as “BSD” (Berkeley Software Distribution):

•BSD Unix proved very popular and was adopted by many commercial startups including Sun Microsystems who used it as the basis for SunOS. Sun later created the Solaris Unix operating system and were acquired by the Oracle Corporation in 2010 - since then that system has been known as Oracle Solaris.

•BSD Unix was adopted for the development of the Darwin operating system – providing the core set of components upon which Apple’s OS X and iOS are based.

•BSD Unix also proved interesting to a 21-year old student at the University of Helsinki. He released his own lightweight Unix variant specifically for PCs. His name was Linus Torvalds and he named his operating system “Linux” – (LINUs’ uniX). Many variations of this popular release have subsequently been developed including Red Hat, Ubuntu, and the Raspbian OS for the Raspberry Pi device.

“Multics” (MULTiplexed Information and Computing Service) was the forerunner to “Unics” (UNiplexed Information and Computing Service) – a.k.a. “Unix”.

Only Oracle Solaris, Apple OS X, HP-UX and IBM’s AIX systems are fully recognized as Unix – all others are more properly referr...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Preface
• 1 Getting started
• 2 Managing files
• 3 Handling text
• 4 Editing commands
• 5 Customizing environment
• 6 Controlling behavior
• 7 Performing operations
• 8 Directing flow
• 9 Employing functions
• 10 Handy reference
• Back Cover