Regular Expressions 101

(?s)applies the following effective flags to the remainder of the pattern: gs

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

Non-Capturing Group(?:\G(?!^)|\bworld\b)

1st Alternative\G(?!^)

\Gstart of current search

Negative Lookahead(?!^)

^start of string

2nd Alternative\bworld\b

\ban ASCII word boundary

worldthe literal text world (case sensitive)

\ban ASCII word boundary

.*?any character, repeated any number of times

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

\ban ASCII word boundary

hellothe literal text hello (case sensitive)

\ban ASCII word boundary

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

Regular Expression

(?s)(?:\G(?!^)|\bworld\b).*?\K\bhello\b

New

blah blah blah
hello
blah blah blah
class="world" 
blah blah blah
hello 
blah blah
hello
blah blah blah
hello
blah blah blah

blah blah blah
hello
blah blah blah
class="world" 
blah blah blah
hello 
blah blah
hello
blah blah blah
hello
blah blah blah