Regular Expressions 101

Pro

Non-Capturing Group(?:\G|\Qhttp://10.20.0.30:1234/index.php\E[^_]+)

1st Alternative\G

\Gstart of current search

2nd Alternative\Qhttp://10.20.0.30:1234/index.php\E[^_]+

\Qhttp://10.20.0.30:1234/index.php\Ethe literal text http://10.20.0.30:1234/index.php (case sensitive)

Negated Character Class[^_]+

+matches at least one character outside the set below:

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

Group 1([^_.]*)

Negated Character Class[^_.]*

*matches any number of characters outside the set below:

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Global pattern flags

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

Detailed match information will be displayed here automatically.

25 tokens

(?:\G|\Qhttp://10.20.0.30:1234/index.php\E[^_]+)\K_([^_.]*)

New

</p><p><a rel="nofollow" class="external text" href="http://10.20.0.30:1234/index.php/this_is_an_example.html">How_to_sample.</a>';

$1

</p><p><a rel="nofollow" class="external text" href="http://10.20.0.30:1234/index.php/this_is_an_example.html">How_to_sample.</a>';