Regular Expressions 101

Explanation

Pro

Group 1(@)?

?repeats the group contents below at most once:

@the literal @ (64₁₀ / 100₈ / 40₁₆)

{{the literal text {{

Non-Capturing Group(?:(?!@{{).)*?

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

Negative Lookahead(?!@{{)

@{{the literal text @{{

.any character (except for line terminators)

}}the literal text }}

Condition(?(1)@|)

Uses the first branch if group 1 matched

If the condition is true, match this branch:@

@the literal @ (64₁₀ / 100₈ / 40₁₆)

Otherwise, match this branch: — matches an empty string

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

(@)?{{(?:(?!@{{).)*?}}(?(1)@|)

New

A @{{Quick}}@ brown @{{fox}}@ jumps @{{over}}@ a lazy {{dog}}.
A @{{Quick}}@ brown @{{fox jumps @{{over}}@ a lazy {{dog}}.