Heredoc syntax for multiline strings in Ruby

Introduction

Heredoc lets you write long text across many lines easily, just like writing a paragraph on paper.

When you want to store a long message or letter in your program.

When you need to write code or text that spans multiple lines without using many quotes.

When you want to keep your text neat and readable in your code.

When you want to include formatted text like poems or instructions.

When you want to avoid using many plus signs or backslashes for line breaks.

Syntax

Ruby

<<IDENTIFIER
Your multiline text goes here
IDENTIFIER

The IDENTIFIER can be any word you choose, but it must match at the start and end.

The ending IDENTIFIER must be alone on its line with no spaces before or after.

Examples

Basic heredoc with the identifier TEXT.

Ruby

<<TEXT
Hello,
This is a multiline string.
TEXT

Using <<- allows indentation before the ending identifier.

Ruby

<<-DOC
Line one
Line two
  DOC

Using <<~ removes common leading spaces for neat indentation.

Ruby

<<~MSG
  Indented line one
  Indented line two
MSG

Sample Program

This program stores a multiline greeting message using heredoc and prints it.

Ruby

message = <<~GREETING
  Hello friend,
  Welcome to learning Ruby!
  Enjoy coding.
GREETING

puts message

Important Notes

Heredoc keeps the line breaks exactly as you write them, so your text looks the same when printed.

Using <<~ helps keep your code tidy by removing extra spaces at the start of each line.

Make sure the ending identifier is not indented unless you use <<- or <<~.

Summary

Heredoc lets you write long text easily across many lines.

Use <

<<~ helps remove extra spaces so your code stays clean and readable.