Why file handling matters in Ruby

Introduction

File handling lets your program save and read information from files. This helps keep data safe even after the program stops.

Saving user settings so they stay the same next time you open the app.

Reading a list of names or data from a file to use in your program.

Writing logs to track what your program did during its run.

Storing scores or progress in a game so players can continue later.

Syntax

Ruby

File.open('filename', 'mode') do |file|
  # read or write using file
end

Use 'r' mode to read, 'w' to write (overwrite), and 'a' to add (append) to a file.

The block ensures the file closes automatically after use.

Examples

This writes 'Hello, world!' to example.txt, creating or replacing the file.

Ruby

File.open('example.txt', 'w') do |file|
  file.puts 'Hello, world!'
end

This reads all content from example.txt and prints it.

Ruby

File.open('example.txt', 'r') do |file|
  content = file.read
  puts content
end

Sample Program

This program writes a greeting to a file, then reads and prints it.

Ruby

File.open('greeting.txt', 'w') do |file|
  file.puts 'Hi there!'
end

File.open('greeting.txt', 'r') do |file|
  puts file.read
end

Important Notes

Always close files or use blocks to avoid errors and free resources.

File modes control if you read, write, or add to files.

Summary

File handling saves and loads data outside your program.

Use different modes to read or write files safely.

Blocks help manage files by closing them automatically.