Regular Expressions 101

Non-Capturing Group(?:\A|\n{2})

1st Alternative\A

\Astart of string

2nd Alternative\n{2}

\n{2}a line-feed (newline) character (ASCII 10), repeated exactly 2 times

Non-Capturing Group(?:\n{2}(*SKIP)(*FAIL)|.)+?

+?repeats the group contents below at least once:

1st Alternative\n{2}(*SKIP)(*FAIL)

\n{2}a line-feed (newline) character (ASCII 10), repeated exactly 2 times

(*SKIP)acts like (*PRUNE), but the next unanchored match attempt starts where (*SKIP) was reached instead of at the next subject character

(*FAIL)forces the current match attempt to fail at this position

2nd Alternative.

.any character

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Positive Lookahead(?=\n{2}|\Z)

1st Alternative\n{2}

\n{2}a line-feed (newline) character (ASCII 10), repeated exactly 2 times

2nd Alternative\Z

\Zend of string, or before its final line terminator

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

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Search reference

Regular Expression

(?:\A|\n{2})(?:\n{2}(*SKIP)(*FAIL)|.)+?\.(?=\n{2}|\Z)

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