Intro

Besides single quoutes and double quotes, there is a third way of delimiting strings in lots of programming languages: Heredocs

How it works

Basically the content is prepended with two (or in some languages more) <, followed by a delimiter string (that should only be used in the content when escaped). Next is the content itself, which ends when the delimiter string follows again on a new line.

Example

$hereDoc = <<<START
I'm
a "here doc"
START;

echo $hereDoc;
Robins-MacBook-Pro-2:heredocs robin$ php heredocs.php
I'm
a "here doc"
Huzza!
Robins-MacBook-Pro-2:heredocs robin$

The cool thing is, you need to escape neither single nor double quotes in a here doc.

Ruby

When starting a here doc in Ruby <<TEXT, it literally means that the string content starts on the next line and ends when TEXT is the sole content on a line. This makes it actually possible to start a here doc and have its content (which follows beginning the next line) interpolated at the here doc starting point.

Example

replaced_text = <<TEXT.sub 'want', 'need'
We
want
you
TEXT

p replaced_text
Robins-MacBook-Pro-2:heredocs robin$ ruby heredocs.rb
"We\nneed\nyou\n"
Robins-MacBook-Pro-2:heredocs robin$