Regular Expressions 101

Group 1(<p id="nav">)

<p id="nav">the literal text <p id="nav"> (case sensitive)

\s?optionally matches any whitespace character

Group 2(.*?)

.*?any character (except for line terminators), repeated any number of times

\s?optionally matches any whitespace character

Group 3(<\/p>)

<the literal < (60₁₀ / 74₈ / 3C₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

p>the literal text p> (case sensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(<p id="nav">)\s?(.*?)\s?(<\/p>)

New

<p id="nav">
<a href="http://tenupclp.dev/wp-login.php?action=register">Register</a> | 	<a href="http://tenupclp.dev/wp-login.php?action=lostpassword">Lost your password?</a>
</p>

Substitution

$1fart$3