regex101: PCRE (Legacy) Match Workspace

Pro

^start of line

Group 1(from|to|cc|bcc)

1st Alternativefrom

fromthe literal text from (case sensitive)

2nd Alternativeto

tothe literal text to (case sensitive)

3rd Alternativecc

ccthe literal text cc (case sensitive)

4th Alternativebcc

bccthe literal text bcc (case sensitive)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

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

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

*repeats the group contents below any number of times:

\Ra newline sequence

Negative Lookahead(?!(?:(?1)|$))

Non-Capturing Group(?:(?1)|$)

1st Alternative(?1)

(?1)calls group 1 as a subroutine

2nd Alternative$

$end of line

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

25 tokens

Regular Expression

^(from|to|cc|bcc):.*(?:\R(?!(?:(?1)|$)).*)*

New

From support@test.co.uk  Wed Nov 20 15:48:00 2013
Return-Path: <support@test.co.uk>
X-Original-To: mailbox@my.domain.com
Delivered-To: mailbox@my.domain.com
Delivered-To: techinfo@test.co.uk
from: "Lucy 1" <support@lucky1.co.uk>,"Lucy 2" <support@lucky2.co.uk>,
"Lucy 3" <support@lucky3.co.uk>
to: TestTo <techinfo@test.co.uk>


testestest

Substitution

From support@test.co.uk  Wed Nov 20 15:48:00 2013
Return-Path: <support@test.co.uk>
X-Original-To: mailbox@my.domain.com
Delivered-To: mailbox@my.domain.com
Delivered-To: techinfo@test.co.uk
from: "Lucy 1" <support@lucky1.co.uk>,"Lucy 2" <support@lucky2.co.uk>,
"Lucy 3" <support@lucky3.co.uk>
to: TestTo <techinfo@test.co.uk>


testestest