$/ = undef;
open FILE, '<', $_;
my $file = <FILE>;
$/ = "\n";
close FILE;

my @matches = $file =~ /((?:.*\n?){$lines_up})
          (.*$pattern.*\n?)
          ((?:.*\n?){$lines_down})/x;

my @parts = qw(lines_up matched_line lines_down);

for (@matches) {
    if (! (my $index = $run++ % 3)) {
        print "match #" . (int($run / 3) + 1) . " in file\n";
    }

    print $parts[$index] . ":\n$_\n";
}