Command-Line Rust

Command-Line Rust

by Ken Youens-Clark
Released January 2022
Publisher(s): O'Reilly Media, Inc.
ISBN: 9781098109431

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Book description

Updated in 2024: A new version has been released that simplifies the programs used in the book, based on changes in the Rust language and crates since original publication. The code has been updated to reflect version 4 of the clap crate.

For several consecutive years, Rust has been voted "most loved programming language" in Stack Overflow's annual developer survey. This open source systems programming language is now used for everything from game engines and operating systems to browser components and virtual reality simulation engines. But Rust is also an incredibly complex language with a notoriously difficult learning curve.

Rather than focusing on the language as a whole, this guide teaches Rust using a single small, complete, focused program in each chapter. Author Ken Youens-Clark shows you how to start, write, and test each of these programs to create a finished product. You'll learn how to handle errors in Rust, read and write files, and use regular expressions, Rust types, structs, and more.

Discover how to:

  • Use Rust's standard libraries and data types such as numbers, strings, vectors, structs, Options, and Results to create command-line programs
  • Write and test Rust programs and functions
  • Read and write files, including stdin, stdout, and stderr
  • Document and validate command-line arguments
  • Write programs that fail gracefully
  • Parse raw and delimited text manually, using regular expressions and Rust crates
  • Use and control randomness

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Table of contents

  1. Preface
    1. What Is Rust (and Why Is Everybody Talkin’ About It)?
    2. Who Should Read This Book
    3. Why You Should Learn Rust
    4. The Coding Challenges
    5. Getting Rust and the Code
    6. March 2024 Update
    7. Conventions Used in This Book
    8. Using Code Examples
    9. O’Reilly Online Learning
    10. How to Contact Us
    11. Acknowledgments
  2. 1. Truth or Consequences
    1. Getting Started with “Hello, world!”
    2. Organizing a Rust Project Directory
    3. Creating and Running a Project with Cargo
    4. Writing and Running Integration Tests
      1. Adding Project Dependencies
      2. Understanding Program Exit Values
      3. Testing the Program Output
      4. Exit Values Make Programs Composable
    5. Summary
  3. 2. Test for Echo
    1. How echo Works
    2. Getting Started
      1. Accessing the Command-Line Arguments
      2. Adding clap as a Dependency
      3. Parsing Command-Line Arguments Using clap
      4. Creating the Program Output
    3. Writing Integration Tests
      1. Creating the Test Output Files
      2. Comparing Program Output
      3. Using the Result Type
    4. Using clap Derive
    5. Summary
  4. 3. On the Catwalk
    1. How cat Works
    2. Getting Started
      1. Starting with Tests
      2. Defining the Parameters
      3. Iterating Through the File Arguments
      4. Opening a File or STDIN
      5. Using the Test Suite
    3. Solution
      1. Reading the Lines in a File
      2. Printing Line Numbers
    4. Going Further
    5. Summary
  5. 4. Head Aches
    1. How head Works
    2. Getting Started
      1. Defining the Arguments
      2. Processing the Input Files
      3. Reading Bytes Versus Characters
    3. Solution
      1. Reading a File Line by Line
      2. Preserving Line Endings While Reading a File
      3. Reading Bytes from a File
      4. Printing the File Separators
    4. Going Further
    5. Summary
  6. 5. Word to Your Mother
    1. How wc Works
    2. Getting Started
      1. Iterating the Files
      2. Writing and Testing a Function to Count File Elements
    3. Solution
      1. Counting the Elements of a File or STDIN
      2. Formatting the Output
    4. Going Further
    5. Summary
  7. 6. Den of Uniquity
    1. How uniq Works
    2. Getting Started
      1. Defining the Arguments
      2. Testing the Program
      3. Processing the Input Files
    3. Solution
    4. Going Further
    5. Summary
  8. 7. Finders Keepers
    1. How find Works
    2. Getting Started
      1. Defining the Arguments
      2. Validating the Arguments
      3. Finding All the Things
    3. Solution
    4. Conditionally Testing on Unix Versus Windows
    5. Going Further
    6. Summary
  9. 8. Shave and a Haircut
    1. How cut Works
    2. Getting Started
      1. Defining the Arguments
      2. Validating the Delimiter
      3. Requirements for Parsing the Position List
      4. Solution for Parsing the Position List
      5. Extracting Characters or Bytes
      6. Parsing Delimited Text Files
    3. Solution
      1. Selecting Characters from a String
      2. Selecting Bytes from a String
      3. Selecting Fields from a csv::StringRecord
      4. Final Boss
    4. Going Further
    5. Summary
  10. 9. Jack the Grepper
    1. How grep Works
    2. Getting Started
      1. Defining the Arguments
      2. Finding the Files to Search
      3. Finding the Matching Lines of Input
    3. Solution
    4. Going Further
    5. Summary
  11. 10. Boston Commons
    1. How comm Works
    2. Getting Started
      1. Defining the Arguments
      2. Validating and Opening the Input Files
      3. Processing the Files
    3. Solution
    4. Going Further
    5. Summary
  12. 11. Tailor Swyfte
    1. How tail Works
    2. Getting Started
      1. Defining the Arguments
      2. Parsing and Validating the Command-Line Arguments
      3. Parsing Positive and Negative Numeric Arguments
      4. Using a Regular Expression to Match an Integer with an Optional Sign
      5. Processing the Files
      6. Counting the Total Lines and Bytes in a File
      7. Finding the Starting Line to Print
      8. Finding the Starting Byte to Print
      9. Testing the Program with Large Input Files
    3. Solution
      1. Counting All the Lines and Bytes in a File
      2. Finding the Start Index
      3. Printing the Lines
      4. Printing the Bytes
      5. Benchmarking the Solution
    4. Going Further
    5. Summary
  13. 12. Fortunate Son
    1. How fortune Works
    2. Getting Started
      1. Defining the Arguments
      2. Finding the Input Sources
      3. Reading the Fortune Files
      4. Randomly Selecting a Fortune
      5. Printing Records Matching a Pattern
    3. Solution
    4. Going Further
    5. Summary
  14. 13. Rascalry
    1. How cal Works
    2. Getting Started
      1. Defining and Validating the Arguments
      2. Writing the Program
    3. Solution
    4. Going Further
    5. Summary
  15. 14. Elless Island
    1. How ls Works
    2. Getting Started
      1. Defining the Arguments
      2. Finding the Files
      3. Formatting the Long Listing
      4. Displaying Octal Permissions
      5. Testing the Long Format
    3. Solution
    4. Notes from the Testing Underground
    5. Going Further
    6. Summary
  16. Epilogue
  17. Index
  18. About the Author

Product information

  • Title: Command-Line Rust
  • Author(s): Ken Youens-Clark
  • Release date: January 2022
  • Publisher(s): O'Reilly Media, Inc.
  • ISBN: 9781098109431