Mastering Unix Shell Scripting

Randal K. Michael is a UNIX Systems Administrator working as a contract consultant. He teaches UNIX shell scripting in corporate settings, where he writes shell scripts to address a variety of problems and tasks ranging from monitoring systems to replicating large databases. He has more than 30 years of experience in the industry and 15 years of experience as a UNIX Systems Administrator, working on AIX, HP-UX, Linux, OpenBSD, and Solaris.

Acknowledgments xxv

Introduction xxvii

Part One The Basics of Shell Scripting

Chapter 1 Scripting Quick Start and Review 3

Chapter 2 24 Ways to Process a File Line-by-Line 67

Chapter 3 Automated Event Notification 131

Chapter 4 Progress Indicators Using a Series of Dots, a Rotating Line, or Elapsed Time 143

Part Two Scripts for Programmers, Testers, and Analysts

Chapter 5 Working with Record Files 157

Chapter 6 Automated FTP Stuff 187

Chapter 7 Using rsync to Efficiently Replicate Data 219

Chapter 8 Automating Interactive Programs with Expect and Autoexpect 291

Chapter 9 Finding Large Files and Files of a Specific Type 325

Chapter 10 Process Monitoring and Enabling Pre-Processing, Startup, and Post-Processing Events 335

Chapter 11 Pseudo-Random Number and Data Generation 369

Chapter 12 Creating Pseudo-Random Passwords 401

Chapter 13 Floating-Point Math and the bc Utility 433

Chapter 14 Number Base Conversions 475

Chapter 15 hgrep: Highlighted grep Script 515

Chapter 16 Monitoring Processes and Applications 527

Part Three Scripts for Systems Administrators

Chapter 17 Filesystem Monitoring 553

Chapter 18 Monitoring Paging and Swap Space 603

Chapter 19 Monitoring System Load 641

Chapter 20 Monitoring for Stale Disk Partitions (AIX-Specific) 677

Chapter 21 Turning On/Off SSA Identification Lights 697

Chapter 22 Automated Hosts Pinging with Notification of Failure 723

Chapter 23 Creating a System-Configuration Snapshot 741

Chapter 24 Compiling, Installing, Configuring, and Using sudo 777

Chapter 25 Print-Queue Hell: Keeping the Printers Printing 809

Chapter 26 Those Pesky Sarbanes-Oxley (SOX) Audits 851

Chapter 27 Using Dirvish with rsync to Create Snapshot-Type Backups 867

Chapter 28 Monitoring and Auditing User Keystrokes 935

Appendix A What’s on the Web Site 955

Index 977