It's simple: you need to know how to work with the bash shell if you want to get to the heart of Mac OS X, Linux, and other Unix systems. Updated for the most recent version of bash, this concise little book puts all of the essential information about bash right at your fingertips, in a format that makes browsing easy. You'll quickly find answers to annoying questions that always come up when you're writing shell scripts: What characters do you need to quote? How do you get variable substitution to do exactly what you want? How do you use arrays? And much more.If you're a user or programmer of any Unix variant, or if you're using bash on Windows, you'll find this pocket reference indispensable. This book covers: Invoking the Shell Syntax Functions Variables Arithmetic Expressions Command History Programmable Completion Job Control Shell Options Command Execution Coprocesses Restricted Shells Built-in Commands.