Regular Expressions 101

^start of line

Non-Capturing Group(?:.*?\d{8}_){0}

{0}repeats the group contents below exactly 0 times:

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

\d{8}a digit, repeated exactly 8 times

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

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

Group 1(\d{8})

\d{8}a digit, repeated exactly 8 times

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

^(?:.*?\d{8}_){0}.*?(\d{8})

New

XXXXX_20160207_20180208_XXXXXXX_20190408T160742_xxxxx
XXXXX_20160207_XXXXXXX_20180208_20190408T160742_xxxxx
XXXXX_20160207_XXXXXXX_20190408T160742_xxxxx
20160207_20180208_XXXXXXX_20190408T160742_xxxxx