The Ruby Way: Solutions and Techniques in Ruby Programming, Second Edition

2.3. Using Here-Documents

If you want to represent a long string spanning multiple lines, you can certainly use a regular quoted string:

str = "Once upon a midnight dreary,
       While I pondered, weak and weary..."

However, the indentation will be part of the string.

Another way is the here-document, a string that is inherently multiline. (This concept and term are borrowed from older languages and contexts.) The syntax is the << symbol, followed by an end marker, then zero or more lines of text, and finally the same end marker on a line by itself:

str = <<EOF
Once upon a midnight dreary,
While I pondered weak and weary,...
EOF

Be careful about things such as trailing spaces on the final end marker line. Current versions of Ruby will fail to recognize ...