Quick Answer

Missing end keywords or unbalanced delimiters

Understanding the Issue

This syntax error occurs when Ruby reaches the end of file while expecting more code (missing "end", closing bracket, etc.).

The Problem

This code demonstrates the issue:

Ruby Error 
# Problem: Missing end
def greet
  puts "Hello"

The Solution

Here's the corrected code:

Ruby Fixed 
# Solution: Add missing end
def greet
  puts "Hello"
end

# Also check:
[1, 2, 3].each { |n| puts n } # Balanced {}

Key Takeaways

Count your opening/closing keywords and delimiters.