The Book of Batch Scripting: From Fundamentals to Advanced Automation

Praise for The Book of Batch Scripting
Title Page
Copyright
Dedication
About the Author and Technical Reviewer
Epigraph
Acknowledgments
Introduction
	This Book’s Audience
	How to Read This Book
	How This Book Is Structured
	Other Resources
	Notes on Style
	Batveats
	Woody Guthrie
	For the Love of Batch
Part I: The Essentials
	1. Batch
		The MS-DOS Command Prompt
		The Batch Scripting Language
		Bat Files
		Your First Bat File
		cmd Files
		Editor Recommendations
		The Batch Interpreter
		Summary
	2. Variables and Values
		Setting and Resolving a Variable
		Displaying the Value of a Variable
			Writing to the Console
			Cleaning Up the Console
		The Idiosyncrasies of the set Command
			Case Sensitivity
			Valid Variable Characters
			Spaces Around the Assignment Operator
		The Command Separator
			Appending Remarks to a Command
			Terminating a Command
		Displaying Variable Information
		Persistently Setting a Variable
		Command Line Help
		Summary
	3. Scope and Delayed Expansion
		Scope
		Delayed Expansion
			Values and Variables
			Partial Variable Names
		Command Extensions
		Final Thoughts on setlocal and endlocal
		Summary
	4. Conditional Execution
		The Basic if Command
		The Conditional Clause
			Compare Operators
			Conditional Clause Keywords
			The Case-Insensitive Option
			The errorlevel Variable
		The if…else Construct
		The else if Construct
		Enhanced Equality Determination Techniques
			The Preceding Dot Technique
			The Double Quotes Technique
			Preceding Dot vs. Double Quotes
		Summary
	5. String and Boolean Data Types
		Common Data Types
		Characters
		Strings
			Build and Concatenate
			Substrings
			Text Replacement
		Booleans
			Setting and Evaluating Booleans
			Converting Booleans to Strings
		Summary
	6. Integer and Float Data Types
		An Octals Case Study
		Integers
		Batch Arithmetic
		Augmented Assignment Operators
		Order of Operation
		Octal and Hexadecimal Arithmetic
		Floating-Point Numbers
		An Octals Case Study, Continued
		Summary
	7. Working With Files
		Commands for Copying Files
			copy
			xcopy
			robocopy
		File Masks and Wildcards
			The Asterisk Wildcard Character
			The Question Mark Wildcard Character
		Moving Files
		Deleting Files
		Renaming Files
		Summary
	8. Executing Compiled Programs
		Calling an Executable
		The cd Command and Variable
		The path Command and Variable
		Finding an Executable
		Pushing and Popping the Current Directory
		Finding Other Resources with the Current Directory
		Passing Arguments to an Executable
		Summary
	9. Labels and Nonsequential Execution
		Labels
		Indentation
		The goto Command
			Branching Forward
			Branching Backward
		The :eof Label
		Variable Labels
		Summary
	10. Calling Routines and Bat Files
		The call Command, Revisited
		Calling Internal Routines
		Calling Bat Files
		Notes on Calling a Label
		Launching Bat Files
		The exit Command
		Summary
	11. Parameters and Arguments
		Passing Arguments
			Argument Delimiters
			Argument Encasing
			Argument Variables
		Accepting Parameters
			Resolving Parameters with a Tilde
			Resolving the Entire Parameter List
		Internal Routine Parameters
		The Hidden Parameter
		Shifting Parameters
		Returning Parameters
		One Variable as Input and Output
		Input Parameter Lists of Varying Lengths
		Drag-and-Drop Parameters
		Summary
	12. Outputs, Redirection, and Piping
		Interpreter-Generated vs. Coder-Generated Output
		stdout and stderr
		Writing Files
			From Coder-Generated Output
			From Interpreter-Generated Output
		Suppressing stdout and stderr
			The @echo off Technique
			The Redirection to nul Technique
		Remarks in stdout
		Redirection of Any Command
		Piping
		stdin
		Summary
	13. Working with Directories
		Directory Basics
			Creating Directories
			Deleting Directories
		Retrieving Directory Information
			The dir Command
			The where Command
		Mapping Drive Letters
			The subst Command
			The net use Command
		Summary
	14. Escaping
		The Problem Statement
		The Caret Escape Character
		Escaping the Caret
		Escaping Percent Signs and Exclamation Marks
		Multilevel Escaping
		The Continuation Character
		Summary
	15. Interactive Batch
		UIs, GUIs, and BUIs
		Choosing a Selection from a List
		Freeform User Input
		Altering the UI Look and Feel
		Fully Functional Batch UI
		Summary
	16. Code Blocks
		Resolving Variables in a Code Block
		The Naked Code Block
		Surviving an endlocal Command
			The “Problem” with the endlocal Command
			The Naked Code Block Solution
		Summary
Part II: The for Command
	17. Fundamentals of the for Command
		Creating Personalized Documentation
		The Optionless for Command
		Filesets, File Masks, and Loops
		Simple Text as Input
		Retrieving File Information
			Modifiers
			Parameters with Modifiers
		Real-World Applications
			Renaming Files on a Backup
			Processing a Variable Number of Files
		Resolving Variables in Code Blocks
		Summary
	18. Directories, Recursion, and Iterative Loops
		The Directory Option
		The Recursion Option
		Directory Recursion
		The Iterative Loop Option
			Power Function Routine
			A Case Study
		Summary
	19. Reading Files and Other Inputs
		The for Command with the /F Option
		Reading the Contents of a File
			Tokenizing the Data
			Defining the Set of Data Delimiters
			Skipping Header Records
			Suppressing Comment Records
		Defining the Input
			File Input
			String Input
			Command Input
		Alternative Syntax for Input Types
			File Input
			String Input
			Command Input
			When to Use usebackq
		Real-World Applications
			Process Only Large Files in a Folder
			Global Text Replacement
		Notes on the Documentation
		Deconstructing Any for Command
		Summary
	20. Advanced for Techniques
		Honoring Nulls
		Forcing a String to Uppercase
			Embedding a PowerShell Command
			Embedding a Python Command
		Two Levels of Delayed Expansion
		Escaping with the for Command
		Summary
Part III: Advanced Topics
	21. Pseudo-Environment Variables
		Date and Time
		Prompt
		Random Numbers
		The cmdcmdline Variable
		System Variables
		Bat Files vs. cmd Files
		Setting Pseudo-Environment Variables
		Summary
	22. Writing Reports
		The Data and Report
		Header Records
		Detail Records
			Aligning Columns with Justified Data
			Working with Floating-Point Data
			Writing a Detail Record
			Working with Counters and Totals
		Trailer Records
		Summary
	23. Recursion
		Defining Recursion
		Factorials
		Decimal to Hexadecimal
		Recursive Directory Searches
		Recursion Stack Overflow
		Summary
	24. Text String Searches
		Searching within a File
			A Simple String
			Customizations
			Multiple Words
		Searching Multiple Files
		Auxiliary Search Files
			File of Search Strings
			File of Files to Search
		Searching a String
		Regular Expressions
			Searching for Any Number
			Searching with Complex Criteria
		Finding the Record Count of a File
		Summary
	25. Bat Files Building Bat Files
		Dynamically Creating a Bat File
		Variable Resolution
		A Real-World Application
		Multigenerational Bat Files
		Recommendations
		Summary
	26. Automatic Restarts and Multithreading
		Five Stages of Intermittent Failures
		The timeout Command
		The Automatic Restart
			The Design Considerations
			The Specifications
			The Auto-Restart Code
			The Testing
			The Central Log
		Hangs
		Retrieving a List of Processes
		Killing Processes
		The Automatic Kill and Restart
			The Design Considerations
			The Specifications
			The Core Auto-Kill-and-Restart Logic
			The Auto-Kill-and-Restart Code
			The Testing
			Real-World Tweaks
		Multithreading
		Summary
	27. And/Or Operators
		The Problem Statement
		Replicating the and Operator
		Replicating the or Operator
			Comparing One Variable to Multiple Values
			Comparing Multiple Variables to One Value
			Comparing Multiple Variables and Values
		The else Keyword
		Summary
	28. Compact Conditional Execution
		Conditional Execution Operators
		Using a Single Operator
			Positive Conditional Execution
			Negative Conditional Execution
			Real-World Applications
		Using Multiple Operators
			A Pseudo if…else Construct
			Multiple && Operators
			Multiple || Operators
			Multiple && vs. Multiple || Operators
		Summary
	29. Arrays and Hash Tables
		Arrays
			Creating Arrays
			Accessing Array Elements
			Initializing an Array
			Implementing Multidimensional Arrays
		Hash Tables
			Arrays vs. Hash Tables
			Basic Hash Table Functionality
			Complex Hash Tables
		Summary
	30. Odds and Ends
		Sorting Files
		The Windows Registry
			Exploring the Registry
			Querying the Registry
		File Attributes
			Retrieving Attributes
			Setting Attributes
		Bit Manipulation
			Bitwise Operations
			Logical Shift Operations
		Summary
	31. Troubleshooting Tips and Testing Techniques
		Capture stdout and stderr
		How to Navigate the Trace
		Don’t Be Fooled by the Ghost Trace
		Create an Audit Trail of Variables
		Understand the stdout of the for Command
		How to Interpret Unresolved Variables
		Recognize Inconsistent Command Outputs
		Write Variables to the Console
		Decipher Different Types of Syntax Errors
		Modularize Wherever Possible
		Test Snippets in a Test Bat File
		Summary
	32. Object-Oriented Design
		Procedural vs. Object-Oriented Coding
		The Four Pillars
		Batch Object-Oriented Design
		Classes and Objects
		Batch Object-Oriented Design Model
			The Parent Object
			The Intermediate Object
			The Child Objects
		Executing Object-Oriented Batch
		Recommendations
		The Four Pillars in Batch
		Summary
	33. Stacks, Queues, and Real-World Objects
		Stacks
		Queues
		Real-World Batch Objects
			The Stack Object
			The Queue Object
		Stack and Queue Applications
		Final Thoughts on Batch Object-Oriented Design
		Summary
Afterword
A. Fully Functional Batch Improv
B. Array and Hash Table Objects
	The Array Object
	The Hash Table Object
Index