Regular Expressions 101

Pro

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

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

Non-Capturing Group(?:.+\n)*?

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

.+any Unicode character (except for line terminators), repeated at least once

\na line-feed (newline) character (ASCII 10)

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

foobarthe literal text foobar (case insensitive)

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

Non-Capturing Group(?:\n.+)*

*repeats the group contents below any number of times:

\na line-feed (newline) character (ASCII 10)

.+any Unicode character (except for line terminators), repeated at least once

Global pattern flags

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

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Detailed match information will be displayed here automatically.

25 tokens

(?m)^(?:.+\n)*?.*foobar.*(?:\n.+)*

New

A1: blah blah
B1: blah blah foobar

A2: foobar blah blah
B2: blah blah foobar
C2: blah blah
D2: blah blah

A3: blah blah
B3: blah blah
C3: blah blah

A1: blah blah
B1: blah blah foobar

A2: foobar blah blah
B2: blah blah foobar
C2: blah blah
D2: blah blah

A3: blah blah
B3: blah blah
C3: blah blah