regex101: PCRE (Legacy) Match Workspace

Pro

<p class="text_obisnuit">the literal text <p class="text_obisnuit"> (case sensitive)

Non-Capturing Group(?:(?!<\/p>)(?!<p).)*

*repeats the group contents below any number of times:

Negative Lookahead(?!<\/p>)

<the literal < (60₁₀ / 74₈ / 3C₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

p>the literal text p> (case sensitive)

Negative Lookahead(?!<p)

<pthe literal text <p (case sensitive)

.any character (except for line terminators)

Non-Capturing Group(?:<.+?>|\z)

1st Alternative<.+?>

<the literal < (60₁₀ / 74₈ / 3C₁₆)

.+?any character (except for line terminators), repeated at least once

>the literal > (62₁₀ / 76₈ / 3E₁₆)

2nd Alternative\z

\zend of string

Global pattern flags

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

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

25 tokens

Regular Expression

<p class="text_obisnuit">(?:(?!<\/p>)(?!<p).)*(?:<.+?>|\z)

New

<p class="text_obisnuit"><em>I have to make sure of that</em></p>

<p class="text_obisnuit"><em>I have to make sure of that</em><br>
<p class="text_obisnuit">I have to make sure of that</div>
<p class="text_obisnuit">I have to make sure of that
</div>

Toto, I have to select all lines that do not end with </p>

your regex  <p class="TEXT">(?:(?!<br>)(?!<p).)*(?:<.+?>|\z)

becomes in this case:

<p class="text_obisnuit">(?:(?!<\/p>)(?!<p).)*(?:<.+?>|\z)

I think I made a mistake somewhere