#!/usr/bin/perl

    use strict;
    use warnings;

    my @buffer;
    my $buffer_size = 10;
    my $match       = qr/toolerror/;

    # Read a file from STDIN.
    while ( my $line = <> ) {

        if ( $line =~ /$match/ ) {

            # Discard the buffered lines.
            @buffer = ();

            # Print the matched line.
            print $line;

        }
        else {

            # Store non matching lines in a buffer.
            push @buffer, $line;

            # Maintain the buffer at a max size.
            if ( @buffer > $buffer_size ) {
                print shift @buffer;
            }
        }
    }

    # Print any remaining buffered lines.
    print @buffer;

    __END__