The bash shell is a complete programming language, not merely a glue to combine external Linux commands. By taking full advantage of shell internals, shell programs can perform as snappily as utilities written in C or other compiled languages. And you will see how, without assuming Unix lore, you can write professional bash 4.0 programs through standard programming techniques.Complete bash coverage Teaches bash as a programming language Helps you master bash 4.0 features What you'll learn Use the shell to write new utilities and accomplish most programming tasks. Use shell parameter expansion to replace many external commands, making scripts very fast. Learn to avoid many common mistakes that cause scripts to fail. Learn how bash's readline and history libraries can save typing when getting user input. Learn to use features new to bash 4.0. Build shell scripts that get information from the Web. Who this book is for Beginning Linux and Unix system administrators who want to be in full command of their systems. Table of Contents Hello, World Your First Shell Program Input, Output, and Throughput Looping and Branching Command-Line Parsing and Expansion Parameters and Variables Shell Functions String Manipulation File Operations and Commands Reserved Words and Builtin Commands Writing Bug-Free Scripts and Debugging the Rest Programming for the Command Line Runtime Configuration Data Processing Scripting the Screen Entry-Level Programming