IO modes (r, w, a) in Ruby - Mini Project: Build & Apply

Working with IO Modes (r, w, a) in Ruby

📖 Scenario: You are managing a simple text file that stores a list of favorite fruits. You want to practice reading from, writing to, and appending to this file using Ruby's IO modes.

🎯 Goal: Build a Ruby program that reads the initial content of a file, overwrites it with new content, then appends additional content, demonstrating the use of r, w, and a modes.

📋 What You'll Learn

Create a text file named fruits.txt with initial fruit names.

Read and display the content of fruits.txt using r mode.

Overwrite fruits.txt with new fruit names using w mode.

Append more fruit names to fruits.txt using a mode.

Print the final content of fruits.txt after all operations.

💡 Why This Matters

🌍 Real World

Managing text files is common for saving logs, user data, or configuration settings in many applications.

💼 Career

Understanding file input/output modes is essential for backend developers, data engineers, and anyone working with file systems.

1

Create the initial file with fruit names

Create a file named fruits.txt and write these exact lines into it: Apple, Banana, and Cherry, each on its own line. Use Ruby's File.open with mode "w" and puts to write the lines.

Ruby

# Create and write initial fruits to 'fruits.txt'
# Your code here

Need a hint?

Use File.open with mode "w" to create and write to the file. Use puts to write each fruit on a new line.

2

Read and display the file content

Open fruits.txt in read mode "r" and read all lines into a variable called content. Then close the file.

Ruby

File.open("fruits.txt", "w") do |file|
  file.puts("Apple")
  file.puts("Banana")
  file.puts("Cherry")
end

# Open 'fruits.txt' in read mode and read content
# Your code here

Need a hint?

Use File.open with mode "r" to read the file. Use read to get all content as a string. Don't forget to close the file.

3

Overwrite the file with new fruits

Open fruits.txt in write mode "w" and overwrite it with these exact fruits: Orange and Grape, each on its own line. Close the file after writing.

Ruby

File.open("fruits.txt", "w") do |file|
  file.puts("Apple")
  file.puts("Banana")
  file.puts("Cherry")
end

file = File.open("fruits.txt", "r")
content = file.read
file.close

# Overwrite 'fruits.txt' with new fruits
# Your code here

Need a hint?

Use File.open with mode "w" again to overwrite the file. Write the new fruits with puts.

4

Append more fruits and print final content

Open fruits.txt in append mode "a" and add these fruits: Kiwi and Mango, each on its own line. Then open the file in read mode "r" and print the entire content stored in final_content.

Ruby

File.open("fruits.txt", "w") do |file|
  file.puts("Apple")
  file.puts("Banana")
  file.puts("Cherry")
end

file = File.open("fruits.txt", "r")
content = file.read
file.close

File.open("fruits.txt", "w") do |file|
  file.puts("Orange")
  file.puts("Grape")
end

# Append fruits to 'fruits.txt' and print final content
# Your code here

Need a hint?

Use File.open with mode "a" to add lines without erasing. Then read the file again and print the content.