The Linux Philosophy for SysAdmins : And Everyone Who Wants To Be One

Table of Contents......Page 5 About the Author......Page 18 About the Technical Reviewer......Page 19 Acknowledgments......Page 20 Part I: Introduction......Page 22 Chapter 1: Introduction to the Linux Philosophy......Page 23 Am I a SysAdmin?......Page 25 The Structure of the Philosophy......Page 27 Who Should Read This Book......Page 29 But I Don’t Meet Those Requirements......Page 30 The Linux Truth......Page 31 Linux Is Open and Free......Page 32 Real Knowledge......Page 33 Enlightenment......Page 34 The Experiments......Page 35 System Requirements......Page 37 How to Access the Command Line......Page 38 Preparing the USB Thumb Drive......Page 39 What to Do if the Experiments Do Not Work......Page 41 Part II: Foundation......Page 42 Text Streams – A Universal Interface......Page 45 STDIO File Handles......Page 46 Generating Data Streams......Page 47 Test a Theory with Yes......Page 49 Exploring the USB Drive......Page 51 Streams of Randomness......Page 57 Summary......Page 59 Chapter 4: Transforming Data Streams......Page 60 Pipe Dreams......Page 61 Building Pipelines......Page 63 Redirection......Page 64 Redirecting STDERR......Page 67 The Problem......Page 69 The Solutions......Page 71 Shortest Solutions......Page 72 Most Creative Solution......Page 73 Thoughts on the Solutions......Page 74 Summary......Page 75 What Is a File?......Page 76 Device File Creation......Page 77 udev Simplification......Page 78 Naming Rules......Page 79 Device Data Flow......Page 80 Device File Classification......Page 81 Fun with Device Files......Page 83 Randomness, Zero, and More......Page 88 Back Up the Master Boot Record......Page 91 Summary......Page 96 Definitions......Page 97 The Standard......Page 98 Using a Well-Defined filesystem Structure......Page 101 Linux Unified Directory Structure......Page 102 Special filesystems......Page 103 The /proc filesystem......Page 104 The /sys filesystem......Page 110 SELinux......Page 115 Problem Solving......Page 117 Using the filesystem Incorrectly......Page 118 Adhering to the Standard......Page 119 Where Does This File Go?......Page 120 Summary......Page 121 Part III: Function......Page 122 Chapter 7: Embrace the CLI......Page 123 Command Prompt......Page 124 Terminal......Page 125 Console......Page 127 Virtual Console......Page 128 Terminal Emulator......Page 129 Session......Page 131 Shell......Page 132 Screen......Page 135 The GUI and the CLI......Page 138 The Mailing List......Page 139 Solution Tenets......Page 141 Baffle Them with Big Data......Page 142 CLI Power......Page 144 Preparation......Page 145 True Productivity......Page 146 Preventative Maintenance......Page 147 Aliases......Page 148 Completion Facility......Page 150 History......Page 153 Using the History......Page 154 SAR......Page 160 Mail Logs......Page 163 messages......Page 164 dmesg......Page 165 secure......Page 166 Following Log Files......Page 169 systemd Logs......Page 170 logwatch......Page 174 Success as a Lazy SysAdmin......Page 177 Why I Use Scripts......Page 178 How I Got Here......Page 179 Making It Easier......Page 180 From Desirable to Necessity......Page 181 Updates......Page 182 Additional Levels of Automation......Page 194 crontab......Page 196 cron.d......Page 199 anacron......Page 201 Thoughts About cron......Page 203 Some Alt Ideas......Page 204 Deepening the Philosophy......Page 205 Definition......Page 207 Requirements......Page 209 Development Speed......Page 210 Performance Speed......Page 211 Testing......Page 212 Shell Scripts as Prototypes......Page 213 Quick and Dirty......Page 214 Planning and Foresight......Page 215 The Code......Page 216 Final Thoughts......Page 227 Chapter 11: Test Early, Test Often......Page 228 Create a Test Plan......Page 229 Test Plan Content......Page 230 Final Testing......Page 231 Testing in Production......Page 232 Fuzzy Testing......Page 233 Automated Testing......Page 234 Trying It Out......Page 235 Requirements for MOTD Script......Page 236 Test Plan for MOTD Script......Page 237 The Basics......Page 238 Add Sanity Checks......Page 242 Version Number......Page 243 Main Body......Page 244 Fixing a Script......Page 256 Summary......Page 257 Script and Program Names......Page 258 Naming Variables......Page 261 Make Everything a Variable......Page 262 Hosts......Page 266 Summary......Page 267 Closed Is Impenetrable......Page 268 Open Is Knowable......Page 269 Flat ASCII Text......Page 270 System Configuration Files......Page 271 Global Bash Configuration......Page 276 User Configuration Files......Page 279 ASCII Rocks......Page 281 Final Thoughts......Page 283 Why We Need Separate filesystems......Page 284 Full filesystems......Page 285 Laptop Lament......Page 286 Data Security......Page 289 Recommendations......Page 290 /boot......Page 291 /home......Page 292 /usr......Page 293 /var......Page 294 The Other Branches......Page 295 Adding Separate filesystems Later......Page 296 Final Thoughts......Page 303 Intel PC to Mainframe......Page 304 Architectures......Page 305 Technology......Page 306 Compilers and Code......Page 307 Shell Scripts......Page 308 Cygwin......Page 309 PowerShell......Page 310 Creating Web Pages......Page 311 Static Content......Page 312 Dynamic Web Pages for a New Job......Page 313 Using Perl......Page 314 Using BASH......Page 317 CGI – Open and Portable......Page 318 WordPress......Page 319 Final Thoughts......Page 320 Definition of Open Source......Page 321 2. Source Code......Page 322 5. No Discrimination Against Persons or Groups......Page 323 9. License Must Not Restrict Other Software......Page 324 Why This Is Important......Page 325 Licensing Our Own Code......Page 326 Silos Suck......Page 328 Open Organizations and Code Sharing......Page 329 Things to Avoid......Page 330 How Do I Share My Code?......Page 331 Confidentiality......Page 332 Providing Support......Page 333 Parting Thoughts......Page 334 Part IV: Becoming Zen......Page 335 Hardware Elegance......Page 336 Motherboards......Page 337 Data Centers......Page 338 Power and Grounding......Page 339 Software Elegance......Page 340 Fixing My Web Site......Page 345 Old or Unused Programs......Page 347 Old Code in Scripts......Page 351 Old Files......Page 352 A Final Word......Page 359 Complexity in Numbers......Page 361 Simplicity in Basics......Page 363 Simple Programs Do One Thing......Page 364 Simple Programs Are Small......Page 367 Simplifying My Own Programs......Page 369 Uncommented Code......Page 370 Hardware......Page 375 Linux and Hardware......Page 376 The Quandary......Page 377 The Last Word......Page 378 Chapter 19: Use Your Favorite Editor......Page 379 Linux Startup......Page 380 Why I Prefer systemd......Page 381 Desktop......Page 382 sudo or Not sudo......Page 383 Bypass sudo......Page 384 Valid Uses for sudo......Page 386 A Few Closing Words......Page 387 Chapter 20: Document Everything......Page 389 The Red Baron......Page 390 The Help Option......Page 391 Comment Code Liberally......Page 392 My Code Documentation Process......Page 395 Systems Documentation......Page 396 System Documentation Template......Page 397 Document Existing Code......Page 400 File Compatibility......Page 401 A Few Thoughts......Page 402 Data Loss......Page 403 The Problem......Page 405 Recovery......Page 412 Backup Options......Page 413 rsync......Page 414 Performing Backups......Page 417 Recovery Testing......Page 420 Off-Site Backups......Page 421 Disaster Recovery Services......Page 422 Summary......Page 423 Charlie......Page 424 Curiosity Led Me to Linux......Page 425 Securiosity......Page 430 Logwatch......Page 431 fail2ban......Page 441 Finding the Sources......Page 443 Collecting the Emails......Page 444 procmail......Page 445 SSH......Page 446 Follow Your Own Curiosity......Page 447 Failure Is an Option......Page 448 Just Do It......Page 449 Summary......Page 450 There Are Always Possibilities......Page 451 Unleashing the Power......Page 452 Problem Solving......Page 453 Critical Thinking......Page 455 Reasoning to Solve Problems......Page 456 Inductive Reason......Page 457 Reason Fails......Page 458 Integrated Reason......Page 459 Finding Your Center......Page 461 The Implications of Diversity......Page 462 Measurement Mania......Page 463 Working Together......Page 464 Silo City......Page 466 The Easy Way......Page 467 Thoughts......Page 468 Chapter 24: Mentor the Young SysAdmins......Page 469 Hiring the Right People......Page 470 Mentoring......Page 471 BRuce the Mentor......Page 472 The Five Steps of Problem Solving......Page 473 Observation......Page 475 Sitting Down on the Job......Page 477 Reasoning......Page 478 Test......Page 479 Example......Page 480 Concluding Thoughts......Page 481 Project Selection......Page 483 Code......Page 484 Submit Bug Reports......Page 485 Documentation......Page 486 Assist......Page 487 Write......Page 488 Donate......Page 489 Thoughts......Page 490 People......Page 491 The Micromanager......Page 492 More Is Less......Page 493 Tech Support Terror......Page 494 You Should Do It My Way......Page 495 The Scientific Method......Page 496 Understanding the Past......Page 497 Final Thoughts......Page 498 Books......Page 499 Web Sites......Page 500 Index......Page 506 Reveals and illustrates the awesome power and flexibility of the command line, and the design and usage philosophies that support those traits. This understanding of how to extract the most from the Linux command line can help you become a better SysAdmin. Understand __why__ many things in the Linux and Unix worlds are done as they are, and how to apply the Linux Philosophy to working as a SysAdmin. The original Unix/Linux Philosophy presented foundational and functional tenets - rules, guidelines, and procedural methods - that worked well. However, it was intended for the developers of those operating systems. Although System Administrators could apply many of the tenets to their daily work, many important tenets were missing. Over the years that David Both has been working with Linux and Unix, he has formulated his own philosophy – one which applies more directly to the everyday life of the System Administrator. This book defines a philosophy, and then illuminates the practical aspects of that philosophy with real-world experiments you can perform. Inspired by David’s real mentors, and dedicated to them, __The Linux Philosophy for System Administrators__ is a mentor to SysAdmins everywhere; remember - "If you fail you learn." **What You Will Learn** * Apply the Linux philosophy to working as a SysAdmin * Unlock the power of the knowledge you already have * Fully understand and access the vast power of the command line * Review the power of Linux as a function of the philosophies that built it **Who This Book Is For** If you want to learn the secrets that make the best Linux SysAdmins powerful far beyond that of mere mortals; if you want to understand the concepts that unlock those secrets; if you want to be the SysAdmin that everyone else turns to when the bytes hit the fan – then this book is for you. Reveals and illustrates the awesome power and flexibility of the command line, and the design and usage philosophies that support those traits. This understanding of how to extract the most from the Linux command line can help you become a better SysAdmin. Understand why many things in the Linux and Unix worlds are done as they are, and how to apply the Linux philosophy to working as a SysAdmin. The original Unix/Linux philosophy presented foundational and functional tenets - rules, guidelines, and procedural methods - that worked well. However, it was intended for the developers of those operating systems. Although System Administrators could apply many of the tenets to their daily work, many important tenets were missing. Over the years that David Both has been working with Linux and Unix, he has formulated his own philosophy - one which applies more directly to the everyday life of the System Administrator. This book defines a philosophy, and then illuminates the practical aspects of that philosophy with real-world experiments you can perform. This book takes place on the Linux command line, but it is not about the commands themselves. The commands are the tools through which the beauty of its underlying structure can be revealed. Inspired by David's real mentors, and dedicated to them, "The Linux Philosophy for system administrators" is a mentor to SysAdmins everywhere; remember - "If you fail, you learn."