wcr - Word Count in Rust

A Rust implementation of the Unix wc command-line tool, built as part of the Coding Challenges series.

Overview

wcr is a word, line, character, and byte count utility that follows the Unix philosophy of doing one thing well. It can read from files or standard input, making it perfect for use in shell pipelines.

Features

• Count bytes (-c): Count the number of bytes in the input
• Count lines (-l): Count the number of lines in the input
• Count words (-w): Count the number of words in the input
• Count characters (-m): Count the number of characters in the input
• Default mode: When no options are provided, displays lines, words, and bytes
• Standard input support: Reads from stdin when no filename is provided
• Zero external dependencies: Uses only Rust's standard library

Installation

Prerequisites

• Rust (edition 2024)

Build from Source

git clone git@github.com:MichaelKlank/wcr.git
cd wcr
cargo build --release

The binary will be located at target/release/wcr.

Install Locally

cargo install --path .

Usage

Basic Usage

Count lines, words, and bytes (default):

wcr file.txt

Command Line Options

Count bytes:

wcr -c file.txt

Count lines:

wcr -l file.txt

Count words:

wcr -w file.txt

Count characters:

wcr -m file.txt

Multiple Options

You can combine multiple options:

wcr -l -w file.txt

Reading from Standard Input

Read from stdin:

cat file.txt | wcr -l

Or:

echo "Hello World" | wcr

Examples

# Default output (lines, words, bytes)
$ wcr test.txt
    7145   58164  342190 test.txt

# Count lines only
$ wcr -l test.txt
    7145 test.txt

# Count words only
$ wcr -w test.txt
   58164 test.txt

# Count bytes only
$ wcr -c test.txt
  342190 test.txt

# Count characters only
$ wcr -m test.txt
  339292 test.txt

# Read from stdin
$ echo "Hello World" | wcr
    1       2      12

Implementation Details

This implementation is written in idiomatic Rust and follows best practices:

• Type safety: Uses Option<T> instead of magic values
• Error handling: Proper error handling with Result<T, E>
• Structured data: Uses structs to organize related data
• Iterator methods: Leverages Rust's iterator API for efficiency
• Zero dependencies: Only uses Rust's standard library

Testing

Run the test suite:

cargo test

About the Challenge

This project was created as part of the Build Your Own wc Tool coding challenge. The challenge encourages developers to build their own version of Unix command-line tools to understand how they work and to practice good software engineering principles.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Acknowledgments

• Inspired by the Coding Challenges series
• Based on the Unix wc command