Regular Expressions 101

<pre>the literal text <pre> (case insensitive)

Group 1((?>(?!</?pre).|(?R))*)

Atomic Group(?>(?!</?pre).|(?R))*

*repeats the group contents below any number of times:

1st Alternative(?!</?pre).

Negative Lookahead(?!</?pre)

<the literal < (60₁₀ / 74₈ / 3C₁₆)

/?optionally matches the literal / (47₁₀ / 57₈ / 2F₁₆)

prethe literal text pre (case insensitive)

.any character

2nd Alternative(?R)

(?R)recurses into the entire pattern

</pre>the literal text </pre> (case insensitive)

Global pattern flags

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

s modifier: single line. Allows a dot to match line terminators

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

<pre>((?>(?!</?pre).|(?R))*)</pre>

New

zzz<pre>sssss<pre>fff</pre>ff</pre>zzz
zzz<pre>sssss<pre>fff</pre>ff</pre>zzz;


<pre>sssss
  <pre>ggg
    <pre>fff</pre>
  </pre>ff
</pre>