minigrep

A simple, minimal implementation of the classic command-line search tool grep, written in Rust as a learning exercise from Chapter 12 of The Rust Programming Language book. This tool, minigrep, is a basic example and not intended for production use; it’s designed to help Rust learners practice working with file I/O, error handling, and command-line arguments.

Overview

minigrep reads a specified file and searches for a provided string, printing each line that contains the string. It demonstrates several core Rust concepts and patterns, including:

• Organizing code effectively
• Using vectors and strings to manage data
• Handling errors gracefully
• Applying traits and lifetimes where needed
• Writing unit tests to validate functionality

Additionally, minigrep introduces some common command-line tool features, such as using environment variables to configure behavior and printing error messages to the standard error stream (stderr).

Note: For a fully-featured and optimized Rust-based search tool, consider using ripgrep by Andrew Gallant.

Features

• Search for a string in a file, displaying each matching line
• Optional case-insensitive search using an environment variable (IGNORE_CASE)
• Basic error handling for missing files or incorrect input

Usage

Prerequisites

• Rust installed on your system

Running minigrep

To run minigrep, clone this repository and build the project:

# Clone the repository
git clone https://github.com/imaazkhalid/minigrep.git
cd minigrep

# Build the project
cargo build

# Run minigrep with search term and file path
cargo run <search_term> <file_path>

Example

Assuming you have a file example.txt with some content:

cargo run to example.txt

This command will print each line in example.txt that contains the word "to".

Case Insensitive Search

Set the IGNORE_CASE environment variable to perform a case-insensitive search:

IGNORE_CASE=1 cargo run to example.txt

Project Structure

This project consists of a single Rust module with the following key files:

• src/main.rs: Contains the main logic for parsing arguments and handling file I/O.
• src/lib.rs: Contains helper functions for search functionality, which are organized to support unit testing.
• tests: Includes tests for various functions in the library.

Concepts Practiced

minigrep builds on several foundational Rust topics:

• File I/O: Reading from files and handling different types of errors.
• Error Handling: Using Rust’s Result and Option types to manage errors gracefully.
• Command-line Argument Parsing: Retrieving command-line arguments using Rust's standard library.
• Environment Variables: Using environment variables to modify the program's behavior.
• Testing: Writing unit tests to verify the correctness of individual functions.

Limitations

This project is intentionally simple, focusing on learning rather than performance. The search is basic and doesn’t support advanced regular expressions. For more powerful and optimized searching capabilities, consider using ripgrep.

Contributing

This project is designed as a learning exercise, so contributions are primarily for educational purposes. Feel free to fork the project and modify it as part of your Rust learning journey.