Rubocop for linting in Ruby

Introduction

Rubocop helps you find and fix mistakes in your Ruby code. It makes your code clean and easy to read.

You want to check your Ruby code for style mistakes before sharing it.

You want to keep your code consistent with common Ruby style rules.

You want to find errors or bad patterns early in your code.

You want to learn good Ruby coding habits by seeing suggestions.

You want to automatically fix simple style problems in your code.

Syntax

Ruby

rubocop [options] [file or directory]

Run this command in your terminal inside your Ruby project folder.

You can check one file or a whole folder of Ruby files.

Examples

Check all Ruby files in the current folder and subfolders.

Ruby

rubocop

Check only the file named my_script.rb.

Ruby

rubocop my_script.rb

Check and automatically fix simple style problems.

Ruby

rubocop --auto-correct

Check only the rule about string quotes (single vs double).

Ruby

rubocop --only Style/StringLiterals

Sample Program

This simple Ruby file prints a message. Running RuboCop on it checks if the code style is good.

Ruby

# Save this as example.rb
puts 'Hello, world!'

# Run RuboCop in terminal:
rubocop example.rb

# Output will show if code follows style rules or has warnings/errors.

Important Notes

RuboCop uses a configuration file .rubocop.yml to customize rules.

You can add RuboCop to your project's Gemfile to keep versions consistent.

Use rubocop --auto-correct carefully; it fixes simple issues but not all problems.

Summary

RuboCop checks your Ruby code for style and errors.

Run it in the terminal with rubocop command.

It helps keep your code clean and consistent.