use strict;
use warnings;

my ( $prevLine, $nextLine );

for ( ; ; ) {
	last if eof DATA;
	chomp( my $currLine = defined $nextLine ? $nextLine : <DATA> );

	if ( $currLine =~ /match this/ ) {
		print '-' x 25, "\n";
		chomp( $nextLine = <DATA> ) if !eof DATA;

		print $prevLine, "\n" if defined $prevLine;
		print $currLine, "\n";
		print $nextLine, "\n" if defined $nextLine;
		print '-' x 25, "\n";
	}
	else {
		undef $nextLine;
	}

	$prevLine = $currLine;
}

__DATA__
The first line match this
Not this
abcdefg
The one above
Another match this 1
Another match this 2
the one below match this 2
zxcvbnn

Another match this blank above
Second to the last line
The last line match this

##</code><code>##

-------------------------
The first line match this
Not this
-------------------------
-------------------------
The one above
Another match this 1
Another match this 2
-------------------------
-------------------------
Another match this 1
Another match this 2
the one below match this 2
-------------------------
-------------------------
Another match this 2
the one below match this 2
zxcvbnn
-------------------------
-------------------------

Another match this blank above
Second to the last line
-------------------------
-------------------------
Second to the last line
The last line match this
-------------------------

##</code><code>##

use strict;
use warnings;

my ( $prevLine, $nextLine, %printed );

for ( ; ; ) {
	last if eof DATA;
	chomp( my $currLine = defined $nextLine ? $nextLine : <DATA> );

	if ( $currLine =~ /match this/ ) {
		chomp( $nextLine = <DATA> ) if !eof DATA;

		print $prevLine, "\n" if defined $prevLine and !$printed{$prevLine}++;
		print $currLine, "\n" if !$printed{$currLine}++;
		print $nextLine, "\n" if defined $nextLine and !$printed{$nextLine}++;
	}
	else {
		undef $nextLine;
	}

	$prevLine = $currLine;
}

__DATA__
The first line match this
Not this
abcdefg
The one above
Another match this 1
Another match this 2
the one below match this 2
zxcvbnn

Another match this blank above
Second to the last line
The last line match this

##</code><code>##

The first line match this
Not this
The one above
Another match this 1
Another match this 2
the one below match this 2
zxcvbnn

Another match this blank above
Second to the last line
The last line match this