Regular Expressions 101

^start of line

Non-Capturing Group(?:.*)

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

Positive Lookbehind(?<=\s)

\sany whitespace character

Group 1(test(?:\s+)?\()

testthe literal text test (case sensitive)

Non-Capturing Group(?:\s+)?

?repeats the group contents below at most once:

\s+any whitespace character, repeated at least once

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Non-Capturing Group(?:.*)

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

$end of line

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^(?:.*)(?<=\s)(test(?:\s+)?\()(?:.*)$

New

This is a test() function
This is a test    () function
test()
test ()
test(
matchtest()


The requirement is to see the word starts with space or is the first word of a line and has an open bracket "(" after that particular word