Learning the Korn Shell

Preface. Korn Shell Versions. Summary of Korn Shell Features. Intended Audience. Code Examples. Chapter Summary. Conventions Used in This Handbook. Acknowledgments. 1: Korn Shell Basics What Is a Shell? Scope of This Book History of UNIX Shells The Korn Shell Features of the Korn Shell Getting the Korn Shell Interactive Shell Use Commands, Arguments, and Options Files Directories Filenames and Wildcards Input and Output Standard I/O I/O Redirection Pipelines Background Jobs Background I/O Background Jobs and Priorities Special Characters and Quoting Quoting Backslash-escaping Quoting Quotation Marks Continuing Lines Control Keys. 2: Command-line Editing Enabling Command-line Editing The History File Emacs Editing Mode Basic Commands Word Commands Line Commands Moving Around in the History File Filename Completion and Expansion Miscellaneous Commands Keyboard Shortcuts with Aliases Vi Editing Mode Simple Control Mode Commands Entering and Changing Text Deletion Commands Moving Around in the History File Character-finding Commands Filename Completion Miscellaneous Commands The fc Command Finger Habits. 3: Customizing Your Environment The .profile File Aliases Tracked Aliases Options Shell Variables Variables and Quoting Built-in Variables Directory Search Path Customization and Subprocesses Environment Variables The Environment File Customization Hints. 4: Basic Shell Programming Shell Scripts and Functions Functions Shell Variables Positional Parameters More on Variable Syntax String Operators Syntax of String Operators Patterns and Regular Expressions Pattern-matching Operators Length Operator Command Substitution Advanced Examples: pushd and popd. 5: Flow Control if/else Exit Status and Return Combinations of Exit Statuses Condition Tests Integer Conditionals for case select while and until. 6: Command-line Options and Typed Variables Command-line Options shift Options with Arguments getopts Integer Variables and Arithmetic Arithmetic Conditionals Arithmetic Variables and Assignment Arrays typeset Local Variables in Functions String Formatting Options Type and Attribute Options Function Options. 7: Input/Output and Command-line Processing I/O Redirectors Here-documents File Descriptors String I/O print read Command-line Processing Quoting eval. 8: Process Handling Process IDs and Job Numbers Job Control Foreground and Background Suspending a Job Signals Control Key Signals kill ps trap Traps and Functions Process ID Variables and Temporary Files Ignoring Signals Resetting Traps Coroutines wait Advantages and Disadvantages of Coroutines Parallelization Coroutines with Two-way Pipes Two-way Pipes Versus Standard Pipes Subshells Subshell Inheritance Nested Subshells. 9: Debugging Shell Programs Basic Debugging Aids Set Options Fake Signals A Korn Shell Debugger Structure of the Debugger The Preamble Debugger Functions Sample kshdb Session Exercises. 10: Korn Shell Administration Installing the Korn Shell as the Standard Shell Environment Customization umask ulimit Types of Global Customization System Security Features Restricted Shell A System Break-in Scenario Tracked Aliases Privileged Mode A: Related Shells The Bourne Shell The IEEE 1003.2 POSIX Shell Standard wksh pdksh bash Workalikes on PC Platforms The Future of the Korn Shell. B: Reference Lists Invocation Options Built-in Commands and Keywords Built-in Shell Variables Test Operators Options Typeset Options Emacs Mode Commands Vi Control Mode Commands C: Obtaining Sample Programs and Problem Set Answers Figures 1: Korn Shell Basics 1-1 The shell is a layer around the UNIX operating system 1-2 A tree of directories and files. 4: Basic Shell Programming 4-1 Ways to run a shell script 4-2 Functions have their own positional parameters. 5: Flow Control 5-1 Files produced by a C compiler. 6: Command-line Options and Typed Variables 6-1 Local variables in functions. 7: Input/Output and Command-line Processing 7-1 Steps in Command-line Processing. 8: Process Handling 8-1 Background Jobs in Multiple Windows 8-2 Coroutine I/O