Efficient Linux at the command line : boost your command-line skills

Want to increase your Linux productivity to get more done in less time? This practical book teaches you how to be quick and efficient at the Linux command line. You'll learn to create and run complex commands that solve real business problems, organize your files for quick access, efficiently process and retrieve information, and automate manual tasks. You'll truly understand what happens behind the shell prompt. Efficient Linux at the Command Line teaches general best practices and the concepts behind them, so no matter which Linux tools you use, you can become more effective in your daily work and more competitive in the job market. You'll learn: How to invent powerful Linux commands on the fly that get your work done quickly. Which Linux features are handled by commands and which are built into the shell that launches those commands--and why it matters. A dozen different ways to run commands, including pipelines, sub-shells, command substitution, process substitution, and more--and when to use each for best advantage. Copyright 4 Table of Contents 5 Preface 11 What You’ll Learn 12 What This Book Is Not 12 Audience and Prerequisites 13 Your Shell 13 Conventions Used in This Book 14 Using Code Examples 15 O’Reilly Online Learning 15 How to Contact Us 15 Acknowledgments 16 Part I. Core Concepts 17 Chapter 1. Combining Commands 19 Input, Output, and Pipes 20 Six Commands to Get You Started 22 Command #1: wc 22 Command #2: head 25 Command #3: cut 25 Command #4: grep 27 Command #5: sort 28 Command #6: uniq 30 Detecting Duplicate Files 32 Summary 34 Chapter 2. Introducing the Shell 35 Shell Vocabulary 36 Pattern Matching for Filenames 36 Evaluating Variables 39 Where Variables Come From 39 Variables and Superstition 40 Patterns Versus Variables 41 Shortening Commands with Aliases 42 Redirecting Input and Output 43 Disabling Evaluation with Quotes and Escapes 45 Locating Programs to Be Run 47 Environments and Initialization Files, the Short Version 49 Summary 50 Chapter 3. Rerunning Commands 51 Viewing the Command History 52 Recalling Commands from the History 53 Cursoring Through History 53 History Expansion 55 Never Delete the Wrong File Again (Thanks to History Expansion) 57 Incremental Search of Command History 59 Command-Line Editing 60 Cursoring Within a Command 61 History Expansion with Carets 62 Emacs- or Vim-Style Command-Line Editing 63 Summary 64 Chapter 4. Cruising the Filesystem 65 Visiting Specific Directories Efficiently 66 Jump to Your Home Directory 66 Move Faster with Tab Completion 67 Hop to Frequently Visited Directories Using Aliases or Variables 68 Make a Big Filesystem Feel Smaller with CDPATH 70 Organize Your Home Directory for Fast Navigation 71 Returning to Directories Efficiently 74 Toggle Between Two Directories with “cd -” 74 Toggle Among Many Directories with pushd and popd 75 Summary 80 Part II. Next-Level Skills 81 Chapter 5. Expanding Your Toolbox 83 Producing Text 84 The date Command 84 The seq Command 85 Brace Expansion (A Shell Feature) 86 The find Command 87 The yes Command 89 Isolating Text 89 grep: A Deeper Look 90 The tail Command 93 The awk {print} Command 94 Combining Text 96 The tac Command 97 The paste Command 97 The diff Command 98 Transforming Text 99 The tr Command 99 The rev Command 100 The awk and sed Commands 101 Toward an Even Larger Toolbox 109 Summary 110 Chapter 6. Parents, Children, and Environments 111 Shells Are Executable Files 112 Parent and Child Processes 113 Environment Variables 115 Creating Environment Variables 116 Superstition Alert: “Global” Variables 117 Child Shells Versus Subshells 118 Configuring Your Environment 119 Rereading a Configuration File 121 Traveling with Your Environment 122 Summary 122 Chapter 7. 11 More Ways to Run a Command 123 List Techniques 123 Technique #1: Conditional Lists 124 Technique #2: Unconditional Lists 125 Substitution Techniques 126 Technique #3: Command Substitution 126 Technique #4: Process Substitution 128 Command-as-String Techniques 131 Technique #5: Passing a Command as an Argument to bash 132 Technique #6: Piping a Command to bash 133 Technique #7: Executing a String Remotely with ssh 135 Technique #8: Running a List of Commands with xargs 136 Process-Control Techniques 140 Technique #9: Backgrounding a Command 140 Technique #10: Explicit Subshells 145 Technique #11: Process Replacement 147 Summary 148 Chapter 8. Building a Brash One-Liner 151 Get Ready to Be Brash 153 Be Flexible 153 Think About Where to Start 154 Know Your Testing Tools 155 Inserting a Filename into a Sequence 156 Checking Matched Pairs of Files 159 Generating a CDPATH from Your Home Directory 161 Generating Test Files 163 Generating Empty Files 166 Summary 167 Chapter 9. Leveraging Text Files 169 A First Example: Finding Files 171 Checking Domain Expiration 172 Building an Area Code Database 174 Building a Password Manager 176 Summary 183 Part III. Extra Goodies 185 Chapter 10. Efficiency at the Keyboard 187 Working with Windows 187 Instant Shells and Browsers 187 One-Shot Windows 188 Browser Keyboard Shortcuts 189 Switching Windows and Desktops 190 Web Access from the Command Line 190 Launching Browser Windows from the Command Line 191 Retrieving HTML with curl and wget 193 Processing HTML with HTML-XML-utils 194 Retrieving Rendered Web Content with a Text-Based Browser 198 Clipboard Control from the Command Line 199 Connecting Selections to stdin and stdout 200 Improving the Password Manager 202 Summary 204 Chapter 11. Final Time-Savers 205 Quick Wins 205 Jumping Into Your Editor from less 205 Editing Files That Contain a Given String 206 Embracing Typos 206 Creating Empty Files Quickly 206 Processing a File One Line at a Time 207 Identifying Commands That Support Recursion 207 Read a Manpage 208 Longer Learning 208 Read the bash Manpage 208 Learn cron, crontab, and at 209 Learn rsync 210 Learn Another Scripting Language 211 Use make for Nonprogramming Tasks 211 Apply Version Control to Day-to-Day Files 213 Farewell 214 Appendix A. Linux Refresher 215 Commands, Arguments, and Options 215 The Filesystem, Directories, and Paths 216 Directory Movement 217 Creating and Editing Files 218 File and Directory Handling 218 File Viewing 220 File Permissions 220 Processes 221 Viewing Documentation 222 Shell Scripts 222 Becoming the Superuser 223 Further Reading 224 Appendix B. If You Use a Different Shell 225 Index 229 About the Author 247 Colophon 247 Take your Linux skills to the next level! Whether you're a system administrator, software developer, site reliability engineer, or enthusiastic hobbyist, this practical, hands-on book will help you work faster, smarter, and more efficiently. You'll learn how to create and run complex commands that solve real business problems, process and retrieve information, and automate manual tasks. You'll also truly understand what happens behind the shell prompt, so no matter which commands you run, you can be more successful in everyday Linux use and more competitive on the job market. As you build intermediate to advanced command-line skills, you'll learn how to: • Choose or invent commands that get your work done quickly • Run commands efficiently and navigate the Linux filesystem with ease • Build powerful, complex commands out of simpler ones • Transform text files and query them like databases to achieve business goals • Control Linux point-and-click features from the command line Take your Linux skills to the next level! Whether you're a system administrator, software developer, site reliability engineer, or enthusiastic hobbyist, this practical, hands-on book will help you work faster, smarter, and more efficiently. You'll learn how to create and run complex commands that solve real business problems, process and retrieve information, and automate manual tasks. You'll also truly understand what happens behind the shell prompt, so no matter which commands you run, you can be more successful in everyday Linux use and more competitive on the job market. As you build intermediate to advanced command-line skills, you'll learn how to: Choose or construct commands that get your work done quickly Run commands efficiently and navigate the Linux filesystem with ease Build powerful, complex commands out of simpler ones Transform text files and query them like databases to achieve business goals Control Linux point-and-click features from the command line This book will take your Linux command-line skills to the next level so you can work faster, smarter, and more efficiently. If you'€™re like most Linux users, you learned your early command-line skills on the job, or by reading an intro book, or by installing Linux at home and just trying things out. I'€™ve written this book to help you take the next step €”to build intermediate to advanced skills at the Linux command line. It'€™s filled with techniques and concepts that I hope will transform how you interact with Linux and boost your productivity. Think of it as a second book on Linux use that takes you beyond the basics. A command line is the simplest of interfaces, yet also the most challenging.