regex101: PCRE (Legacy) Substitution Workspace

(?m)applies the following effective flags to the remainder of the pattern: mg

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

^start of line

Group 1(\d+\R(\d{2}:\d{2}:\d{2},\d{3}) --> (?2))

\d+a digit, repeated at least once

\Ra newline sequence

Group 2(\d{2}:\d{2}:\d{2},\d{3})

\d{2}a digit, repeated exactly 2 times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\d{2}a digit, repeated exactly 2 times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\d{2}a digit, repeated exactly 2 times

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\d{3}a digit, repeated exactly 3 times

--> the literal text -->

(?2)calls group 2 as a subroutine

Non-Capturing Group(?:\R(?!(?1)).*)*?

*?repeats the group contents below any number of times:

\Ra newline sequence

Negative Lookahead(?!(?1))

(?1)calls group 1 as a subroutine

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

\ban ASCII word boundary

Non-Capturing Group(?:Download|Ads)

1st AlternativeDownload

Downloadthe literal text Download (case sensitive)

2nd AlternativeAds

Adsthe literal text Ads (case sensitive)

\ban ASCII word boundary

Character Class[\s\S]*?

*?matches any number of characters from the set below:

\sany whitespace character

\Sany non-whitespace character

Positive Lookahead(?=\s*(?:(?1)|\z))

\s*any whitespace character, repeated any number of times

Non-Capturing Group(?:(?1)|\z)

1st Alternative(?1)

(?1)calls group 1 as a subroutine

2nd Alternative\z

\zend of string

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

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

25 tokens

Regular Expression

(?m)^(\d+\R(\d{2}:\d{2}:\d{2},\d{3}) --> (?2))(?:\R(?!(?1)).*)*?\b(?:Download|Ads)\b[\s\S]*?(?=\s*(?:(?1)|\z))

New

1
00:00:39,243 --> 00:00:45,820
This line is ok

2
00:00:46,243 --> 00:00:51,820
This line with
"Ads" word should be deleted

3
00:01:04,243 --> 00:01:05,820
This line with
"Download" word should be deleted

4
00:01:08,664 --> 00:01:12,331
An ok line

Substitution

$1

1
00:00:39,243 --> 00:00:45,820
This line is ok

2
00:00:46,243 --> 00:00:51,820
This line with
"Ads" word should be deleted

3
00:01:04,243 --> 00:01:05,820
This line with
"Download" word should be deleted

4
00:01:08,664 --> 00:01:12,331
An ok line