flatpress/fp-includes/smarty-4.3.0/docs/designers/language-modifiers/language-modifier-nl2br.md

nl2br

All "\n" line breaks will be converted to html <br /> tags in the given variable. This is equivalent to the PHP's nl2br() function.

<?php

$smarty->assign('articleTitle',
                "Sun or rain expected\ntoday, dark tonight"
                );

?>

Where the template is:

{$articleTitle|nl2br}

Will output:

Sun or rain expected<br />today, dark tonight

See also word_wrap, count_paragraphs and count_sentences.