Regular Expressions 101

Pro

1st Alternative[\s\S]*?(keep\d\s+\{[^{}]*\})

Character Class[\s\S]*?

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

\sany whitespace character

\Sany non-whitespace character

Group 1(keep\d\s+\{[^{}]*\})

keepthe literal text keep (case sensitive)

\da digit

\s+any whitespace character, repeated at least once

\{the literal { (123₁₀ / 173₈ / 7B₁₆)

Negated Character Class[^{}]*

*matches any number of characters outside the set below:

{the literal { (123₁₀ / 173₈ / 7B₁₆)

}the literal } (125₁₀ / 175₈ / 7D₁₆)

\}the literal } (125₁₀ / 175₈ / 7D₁₆)

2nd Alternative(?:(?!keep\d\s+\{[^{}]*\})[\s\S])+$

Non-Capturing Group(?:(?!keep\d\s+\{[^{}]*\})[\s\S])+

+repeats the group contents below at least once:

Negative Lookahead(?!keep\d\s+\{[^{}]*\})

keepthe literal text keep (case sensitive)

\da digit

\s+any whitespace character, repeated at least once

\{the literal { (123₁₀ / 173₈ / 7B₁₆)

Negated Character Class[^{}]*

*matches any number of characters outside the set below:

{the literal { (123₁₀ / 173₈ / 7B₁₆)

}the literal } (125₁₀ / 175₈ / 7D₁₆)

\}the literal } (125₁₀ / 175₈ / 7D₁₆)

Character Class[\s\S]

\sany whitespace character

\Sany non-whitespace character

$end of line

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.

25 tokens

[\s\S]*?(keep\d\s+\{[^{}]*\})|(?:(?!keep\d\s+\{[^{}]*\})[\s\S])+$

New

blah blah Bob Loblaw Law blah
keep1 { i want this } blop
blah blob keep2 { and
this too } blaw blat
etc...

$1\n

blah blah Bob Loblaw Law blah
keep1 { i want this } blop
blah blob keep2 { and
this too } blaw blat
etc...