• \n – new line
• \r – carriage return
• \t – tab
• \b – backspace

But many wonder when to use them or more specifically, why they aren’t working as expected. So let’s address the basic usage and rules.

Rule #1: When using a formatting character in your code, it must be within “double quotations” otherwise it will be taken as a literal backslash and letter.

When do you use it? When writing to a file with fwrite() or file_put_contents(), sending a text email with mail(), or when adding formatting to pre-populated data in the form element <textarea>. Now, notice I made no mention of HTML output directly. While it’s possible to represent new line, tab, carriage return in HTML if it is within the preformatted tags <pre></pre>, in most cases these tags are not present and HTML will ignore these formatting characters.

Rule #2: Not all computer systems obey the formatting characters the same. When using \n (new line), also include a carriage return (\r) character.

So what do you do if you have a paragraph, for instance submitted by a <textarea> form, that is preformatted and want it to display in the HTML with the \n (new line) breaks represented? That’s when you toss the string into the function nl2br(), which changes all \n to the xhtml line break <br />.

Example:

echo nl2br("Hello\n\rWorld\n\r!!!");

Results:

Hello
World
!!!