The text matched by the used group most-recently closed (i.e. the group with the rightmost closing parenthesis) of the last successful match. (See"Scoping Rules of Regex Variables").
This is subtly different from$+. For example in
"ab" =~ /^((.)(.))$/we have
$1,$^N have the value "ab"$2 has the value "a"$3,$+ have the value "b"This is primarily used inside(?{...}) blocks for examining text recently matched. For example, to effectively capture text to a variable (in addition to$1,$2, etc.), replace(...) with
(?:(...)(?{ $var = $^N }))By setting and then using$var in this way relieves you from having to worry about exactly which numbered set of parentheses they are.
This variable is read-only, and its value is dynamically scoped.
This variable was added in Perl v5.8.0.
Mnemonic: the (possibly) Nested parenthesis that most recently closed.
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