=over

=item $PREMATCH

=item $`
X<$`> X<$PREMATCH>

The string preceding whatever was matched by the last successful
pattern match. (See L</Scoping Rules of Regex Variables>).

See L</Performance issues> above for the serious performance implications
of using this variable (even once) in your code.

This variable is read-only, and its value is dynamically scoped.

Mnemonic: C<`> often precedes a quoted string.

=back